Home / Power Supply Repair / 200+ Best Electronics Mini Projects: Circuits, Working Process, Code
Troubleshooting and repairing Switch Mode Power Supplies

200+ Best Electronics Mini Projects: Circuits, Working Process, Code


We would like to provide you with a huge list of electronics mini project ideas for your engineering project work, along with the components list, circuit diagram, code, working principle, and applications. This list has a combination of our own making DIY projects and a few other projects done by hobbyists, also we have divided module wise. Would you like to know more about our weekly project updates, please join us.


Water Level Indicator:

Water Level Indicator is a simple basic famous project in electronics. It employs a simple mechanism which helps to detect and indicate the water level in an overhead tank or any other water container. It can be used in Hotels, Factories, Homes Apartments, Commercial Complexes, Drainage, etc.

Password Based Door Lock System using 8051 Microcontroller:

This system demonstrates a password-based door lock system wherein once the correct code or password is entered, the door is opened and the concerned person is allowed access to the secured area. After some time, the door would be closed automatically. It is fully functional based on the password.

Cell Phone Controlled Robotic Vehicle:

Cell phone controlled the robotic vehicle based on DTMF controller. This is without using the microcontroller. The object will be functional through a cell phone. It can be used in industries and surveillance systems.

Human Detection Robot using 8051 Microcontroller:

The main principle of the circuit is to detect the human using a human detection sensor. The wireless robot is operated manually using PC. The wireless technology used here is Radio Frequency technology. The data is transmitted to the receiver through RF.

SMS Controlled Robot:

GSM controlled robot or SMS controlled robot is a wireless robot which performs the necessary actions by receiving a set of instructions in the form a Short Message Service (SMS).

Remote Password Operated Electronic Home Appliances:

How to control the electrical appliances using an Android device. Here, Bluetooth module is interfaced to 8051 microcontrollers. This Bluetooth receives the commands from the Android application device using wireless communication.

Automatic Room Lights using Arduino and PIR Sensor:

This is a very simple lights project on automatic room lights, where Arduino and PIR sensor automatically turn on and off the room lights.

Automatic Door Opener System using PIR Sensor and Arduino:

In this project, an Arduino and PIR Sensor based Automatic Door Opener System is implemented, whereupon detecting any human movement, the door opens automatically. Mostly we see these kinds of functionality at shopping malls.

DIY RGB LED Matrix:

This is a simple led matrix project through control it is using an android application. This project can be useful in making sign boards, scrolling message boards, etc.

Arduino 8×8 LED Matrix Interface:

This project similar to above project but using Arduino with more LEDs. It shows you how to interface an 8×8 LED Matrix to Arduino. There is a dedicated Android App for this project that you can install and control the 8×8 LED Matrix from a Phone.

Arduino DC Motor Control using L298N:

Using this project, you can control a simple DC Motor using the very popular L298N Motor Driver Module and Arduino. You can control two DC Motors at a time.

DIY Arduino and Bluetooth Controlled Robotic Arm Project:

Very interesting project for who are interested in robotics too. You can build your own robotic arm using the data from this project. This is based on Arduino, Bluetooth and 3d printed robotic arm parts. The main key element is we have used an android mobile application to control this robotic arm.

DIY Arduino Christmas Tree Lights using LEDs:

This is a seasonal project, we can use this kind of project for any special occasion. A holiday-themed project where we will be using an Arduino board to control the led lights arranged on a Christmas tree.

Hand Gesture Controlled Robot using Arduino:

One more interesting project, a simple hand gesture based robotic vehicle is designed. it is designed using Arduino, mpu6050, and rf transmitter-receiver pair.

Obstacle Avoiding Robot using Arduino:

We made this project using arduino. Obstacle avoiding robot can run continuously without hitting any obstacle. Its based on Arduino. We have used an ultrasonic sensor in this project to detect the obstacles.

Heartbeat Sensor using Arduino:

A heart rate monitoring system is designed in this project by using Arduino, also we have included a sensor to detect heartbeat. it is a very simple and effective project where the result can be viewed on an LCD display.

DIY LED Light Bulb (LED Lamp):

This is a simple project, you can do it yourself. we will show you how to make your own LED Lamp using simple hardware. It is based on the transformerless power supply.

Metal Detector Robotic Vehicle:

This is one more interesting and useful project. Landmines buried under the ground causes a threat to the lives and affect the economy of the nation. Detection and removing of these mines manually is a dangerous task. So, we use a metal detection robot which works on RF technology.

Sun Tracking Solar Panel:

This project describes circuit that rotates solar panel. A Sun tracking solar panel consists of two LDRs, solar panel, stepper motor, and ATMEGA8 Microcontroller.

Speed Control of DC Motor Using Pulse Width Modulation:

This pulse width modulation technique is the more efficient way to proceed to manage the speed of our DC motor manually.

Water Level Alarm Using 555 Timer:

This is the similar project we have done already but here we are using different module 555 timer circuit. Very simple and low-cost hardware project. The aim of this project is to design a water level detecting alarm with simple and low-cost hardware without compromising on the performance of the device.

Bidirectional Visitor Counter using 8051:

It is helpful to count the number of persons entering or leaving a room and to display it on a screen. Mostly useful at movie place, shopping malls etc.

Temperature Controlled DC Fan using Microcontroller:

The main principle of the circuit is to switch on the fan connected to DC motor when the temperature is greater than a threshold value. This can be used in home applications and in CPU to reduce heat.

Password-based Circuit Breaker:

This password-based circuit breaker project is built using 8051 controllers and is used to switch off the power supply to the line by entering a password.

Auto Intensity Control of Street Lights:

This is a simple circuit that automatically controls the intensity of street lights which is designed using microcontroller and LEDs.

Line Following Robotic Circuit using ATMega8 Microcontroller:

This line follower robot is a basic robot that follows a specific path indicated by a line having some particular width.

Digital Tachometer using 8051 Microcontroller:

Here we designed a simple non-contact tachometer using the microcontroller which can measure speed with an accuracy of 1 rev/sec.

5 Channel IR Remote Control System using Microcontroller:

This article is aimed to design and demonstrate a simple 5 channel remote control system to drive five loads. This circuit works on the principle of IR communication.

Bipolar LED Driver Circuit:

This bipolar LED driver circuit is very useful at the places where flashing of light is required, as in beacon flashing. This circuit can be mainly used for indication purposes.

Celsius Scale Thermometer using AT89C51:

This Celsius Scale Thermometer circuit is designed using at89c51 and lm35. This circuit works on analog to digital conversion principle. It can be used at homes, mobile places like cars to keep a track of the temperature.

Density Based Traffic Signal System using Microcontroller:

In this system, we use IR sensors to measure the traffic density. We must arrange one IR sensor for each road, these sensors always sense the traffic on that particular road. All these sensors are interfaced to the microcontroller. Based on these sensors, the controller detects the traffic and controls the traffic system.

Automatic Washroom Light Switch:

This is a simple but very useful circuit in our real life which helps to automatically turn On the lights when a person enters the washroom and it automatically turns Off the lights when he leaves it.

Automatic Door Bell with Object Detection:

This automatic doorbell with object detection circuit helps to sense the presence of a person or an object automatically and rings the doorbell.

Boolean Algebra Calculator:

This Boolean algebra calculator is an interesting project which is more useful in our real life by working as a portable calculator to simplify the Boolean expression on the fly. In our circuit, we use Boolean algebra simplification methods like the Quine-McCluskey algorithm to simplify the Boolean expression and display the output on the display.

Auto Night Lamp using High Power LED:

This Auto Night Lamp is an interesting circuit which helps to turn ON the LED lights interfaced to it at night time and it turns OFF the lights automatically when it is the day.

Mobile Jammer Circuit:

This circuit is used to block the signals of cell phones within the range of 100 meters. This circuit can be used in TV transmission and for remote controlled toys or playthings.

Unbiased Digital Dice with LEDs:

This is a circuit diagram of digital dice which is nearly unbiased. By using this circuit, there is no chance to cheat as the circuit operates at such a high speed that the circuit is almost imperceptible to the human eye.

Metal Detector Circuit:

This is a simple metal detector circuit which is very useful for checking the person in shopping malls, hotels, cinema halls to ensure that person is not carrying any explosive metals or illegal things like guns, bombs etc.

Panic Alarm:

This panic alarm circuit helps us to intimate others regarding our bad situation without any delay. It is more useful when an intruder entering our house or bad health status at which we are unable to intimate to the people around us.

Automatic Railway Gate Controller with High-Speed Alerting System:

The main aim of this project is to operate and control the unmanned railway gate in the proper manner in order to avoid the accidents in the unmanned railway crossing.

LED Flasher Circuit:

LED Flasher is a simple circuit which will blink the LEDs in the regular time period. This circuit can be used for decoration purpose or can be used for a signaling purpose and many more.

Dancing Bi-Color LED Lights Circuit:

Generally, we use small voltage bulbs in the dancing bulbs. This circuit is mainly used on the occasions, pubs, decoration articles or in visual indication sign boards etc. Here in this project, we have used a bi-color LEDs for sequential running light.

Intelligent Unambiguous Night Lamp Switcher:

This is the circuit diagram of unambiguous night lamp switch, which turns ON our domestic lights automatically when it is dark, without human interference. It also avoids repeated frequent switching of the devices which is usually ignored in most similar circuits but may have a detrimental effect on our operating devices.

Thermistor Temperature Sensing Alarm:

This circuit is a temperature sensing as well as alarm circuit. The circuit raises an alarm whenever the temperature crosses a certain limit.

Pull Pin Security Alarm System:

This circuit helps us to get alerted when anybody picks our pockets or bags. The circuit is very helpful to prevent our goods getting pickpocketed.

Auto Turn Off Soldering Iron Circuit:

This circuit helps the soldering iron to turn off automatically when it detects overheating and thereby avoids it from getting damaged.

Remote Operated Alarm Circuit:

This circuit rings an alarm when you point a TV remote at it and press on any button. This can be used as a calling bell to call your assistant.

Battery Charger Circuit Using SCR:

Here is the circuit diagram of battery charger circuit using Silicon Controlled Rectifier. SCR can be used in half wave rectifier, full wave rectifier, inverter circuits, power control circuits, etc.

FM Bugger Circuit:

Here is a small circuit with which you can listen to other people conversation from long distance using the normal FM radio set. This FM bugger circuit is kept in the room where you want to listen to the conversation. You can listen to this conversation using the normal FM radio set.

Cell Phone Detector:

This is a simple circuit which helps to detect the presence of an activated cell phone by detecting the signals in the frequency range of 0.9 to 3GHz. It helps in mobile phones tracking which are used for spying.

Battery Powered Portable Light:

This circuit is more helpful in handling unexpected and undesired darkness in our homes or offices. It provides the considerable amount of brightness required to do our daily tasks.

IR Remote Control Switch:

By using this circuit, we can control any household appliance with the help of remote. In this project, there are two parts– one is in the transmitting section and the other is in the receiving section. Receiving section will be in a stable position which is connected to any load and transmitter will act like a normal remote.

Continuity Tester with Melody:

This circuit works as a continuity tester device which tests the continuity of the wire at hand. It is an indispensable tool to check broken wires and undesired shorting of wires.

Rain Alarm Circuit:

Rainwater detector will detect the rain and make an alert; rainwater detector is used in the irrigation field, home automation, communication, automobiles etc. Here is the simple and reliable circuit of rainwater detector which can be constructed at low cost.

Automatic Plant Irrigation System:

This project circuit is more useful in watering plants automatically without any human interference. It is more useful when the owner is not present in the home for a few days.

Hot Water Geyser Controller Circuit:

This circuit is made to turn OFF geysers as soon as our water gets hot and are ready for bathing.

Lead Acid Battery Charger Circuit:

Lead Battery is a rechargeable battery and is more useful in our real life as it will dissipate very little energy, it has the very low energy to weight ratio, it can deliver high current, can work for a long time with high efficiency and is very low cost.

Motion Detector Circuit:

The motion detector is not only used as intruder alarm but also used in many applications like home automation system, energy efficiency system, etc. The motion detector will detect the motion of the people or objects and give the appropriate output according to the circuit.

Touch ON and OFF Switch Circuit:

This Touch ON/OFF Switch circuit is more useful in such a way that we can automatically ON or OFF any switch by touching a device without moving from our place.

USB Mobile Charger Circuit:

This circuit is useful in charging the mobiles through USB outlet present in our laptops and PCs. For the charging of your mobile phone, this circuit provides you a regulated voltage of 4.7 volts.

Security Alarm Circuit:

This circuit helps you to guard your precious documents as well as jeweler from intruders or theft. All you need is to just place this circuit in front of the locker or below the mat so when an unknown person come and walk over the switch, the circuit will trigger, and the sound of alarm comes.

Mosquito Repellent Circuit:

Here is the simple electronic mosquito repellent circuit which can produce ultrasound in the frequency range of 20-38 kHz, which can scare away mosquitoes.

Simple FM Radio Jammer Circuit:

This is a Jammer circuit which is used to block the signals. Jammer circuit produces the high-frequency signal which will confuse the receiver of a particular system from receiving the signal, even though the circuit is working properly, a user of the system feels that the circuit is not working properly.

Automatic Street Light Controller Circuit Using Relays and LDR:

This circuit helps in automatically turn ON/OFF the street lights using relays and LDR. The whole circuit is based on IC CA3140.

Battery Charger Circuit:

This battery charger circuit works on the principle of controlling switching of an SCR based on charging and discharging of the battery.

Interfacing 16×2 LCD with 8051:

This is a simple circuit diagram which helps to describe interfacing of 16X2 LCD module to AT89C51 which is an 8051 family microcontroller.

PWM LED Dimmer Using NE555:

The Pulse Width Modulation (PWM) plays an important role in controlling the circuits. We use this PWM to dim the intensity of light of the LED.

Simple Fire Alarm Circuits:

Here are two simple fire alarm circuits which are used to detect the fire automatically and inform to the people immediately with an alarm.

Wireless Switch Circuit using CD4027:

This is a simple circuit which needs no physical contact with the appliance. In this circuit, all you need is to pass your hand above LDR to ON or OFF the switch.

Electronic Letter Box:

This is a simple circuit which helps in finding out any letter dropped in our box by stopping the LED lights attached in this circuit.

Clap Switch Circuit for Devices:

This is another simple but very useful circuit which helps to ON or OFF a device without moving from you place and helps to control the speed of the electric devices like a fan, etc.

12v DC to 220v AC Converter Circuit:

Here is a simple voltage is driven inverter circuit which converts 12v DC signal to single phase 220v AC using power transistors as a switching device.

FM Transmitter Circuit:

Here we built a wireless FM transmitter which uses RF communication to transmit the medium or low power FM signal. The maximum range of transmission is around 2 km.

100w Subwoofer Amplifier Circuit:

Here are the circuit diagram and working of 100w subwoofer amplifier circuit. A Subwoofer is a loudspeaker which produces audio signals of low frequencies.

DTMF Based Home Automation System Circuit:

This is a simple and very useful circuit in our real life named DTMF controlled home appliances system. It helps to control the home appliances using DTMF technology.

Street Lights that Glow on Detecting Vehicle Movement:

This article describes the circuit that switches the street lights on detecting vehicle movement and remains off after a fixed time. This system controls the street lights using the light dependent resistor and PIR sensor.

555 Timer IC Testing Circuit:

This is a simple 555 IC testing-circuit which tests your entire 555 timer IC. So before using your IC, you may check whether your IC is good or bad by using this circuit.

Curtain Opener/Closer Circuit:

This circuit will open and close the curtain of your home and office just by pushing a switch. So, with the help of this unique circuit, we do not need to move from one place to open and close the curtain.

Variable Power Supply and Charger:

This is a circuit which helps to check or test your electronic projects and also to charge the Mobile phone batteries. This circuit can also work as an emergency light.

LED Running Lights Circuit:

This is a simple circuit consists of 9 LED lights in knight rider scanner mode. It will present an eye-catching look as the LED initially travel in the one way and then travel reverse in the similar direction.

Luggage Security Alarm:

This is a simple alarm circuit which helps in ringing a warning alarm when someone tries to steal the luggage.

9 Way Clap Switch Circuit:

This circuit helps you to manage your appliances in your home by just clap without moving from your bed.

12V to 24V DC Converter Circuit:

This is another kind of circuit which helps to convert 12V DC current to 24V DC current.

230V LED Driver:

Here we design a simple circuit driving a series of LED from 230V AC. This is accomplished using a capacitor-based power supply. This is a low cost and efficient circuit and can be used at homes.

3X3X3 LED Cube:

This is a simple a simple LED cube circuit designed without using the microcontroller. It is based on the principle of driving LEDs using the clock pulses.

Monostable Multivibrator Circuit Operation:

Here is the monostable multivibrator circuit diagram and working. The multivibrator is an electronic circuit which will work as two-stage amplifier operating in both stable and a stable mode.

Interfacing 16X2 LCD with PIC Microcontroller:

This is a circuit which helps in interfacing 16Ã —2 LCD to PIC18F4550 microcontroller which is of family PIC18F.

Morse Code Generator Circuit:

This is a circuit used to generate morse code. Morse code is very old and versatile technique to send text messages using wireless media.

555 Timer in Monostable Multivibrator Mode:

The circuit is triggered by a falling edge, that is, by a sudden transition from HIGH to LOW. The trigger pulse, produced by pressing the button, must be of shorter duration than the intended output pulse.

555 Timer as an Astable Multivibrator:

In this circuit, there are three resistors named R inside it and all have equal values. These form a voltage divider having reference voltages of 1/3 and 2/3 of Vcc (the power supply). The logic state of the flip-flop is controlled by the reference voltage which is given to one of the inputs of both two comparators.

Mains Operated LED Light Circuit:

This is a simple circuit which is more useful to save our resources, energy, and money by installing in your homes.

LED Lamp Dimmer Circuit:

In this circuit, at the starting LED glows slowly, then grown brighter and once again slowly it became dim. The basis of the whole circuit is an operational amplifier IC named LM358.

Variable Voltage Power Supply from Fixed Voltage Regulator:

This Voltage regulator circuit is used to get fixed voltage at the output without depending on the input voltage.

LED Christmas Lights Circuit:

This is a simple circuit used to decorate your house by building Christmas lights using LEDs. The lights will get ON at night and OFF in morning time.

Audio Equalizer Circuit:

The circuit is used to change the tune/melody into a different pitch level by devoid of loss in the tune. It is mainly useful to music lovers.

Air Flow Detector Circuit:

This air flow detector circuit can be used to detect the flow of air in areas like a car engine. It can also be used as a temperature detector.

150W Power Amplifier Circuit:

Here we designed a power amplifier circuit using push-pull class AB configuration to derive a power of 150W to drive a load of 8 Ohms (speaker).

7 Segment LED Display Decoder:

This is the circuit diagram of display decoder which is used to convert a BCD or binary code into a 7 segment code used to operate a 7 segment LED display.

Digital Temperature Sensor:

The main principle of this circuit is to display the digital temperature value. These are mainly used in environmental applications.

Digital Stopwatch Circuit:

This is a simple circuit that displays count from 0 to 59, representing a 60 second time interval. It consists of a 555 timer to produce the clock pulses and two counter ICs to carry out the counting operation.

Toy Organ using 555 Timer IC:

This is the circuit diagram of simple Toy Piano using 555 Timer IC. It produces different tones or sounds depending on the frequency range.

RFID based Attendance System:

This simple RFID based attendance system is designed using ATmega8 Microcontroller and is mainly used in educational institutions, industries, etc. where authentication is needed.

Low Power Audio Amplifier using 555 Timer:

This is a simple low power audio amplification circuit designed using 555 timers. It can be used to develop low power music systems used in vehicles.

Interfacing 16X2 LCD to AVR Microcontroller:

This is a circuit which helps in interfacing 16X2 LCD with AVR Microcontroller. The Atmega16 belongs to the AVR microcontroller family.

SR Flip Flop with NAND and NOR Gates:

SR Flip Flop, also known as SR latch is the most vital as well as broadly used Flip Flop. Get an idea about the design of SR Flip Flop with NAND and NOR Gates.

JK Flip Flop using CD4027:

CD4027 is a JK flip-flop that is generally used for data storing. Get an idea about how to build JK Flip Flop with CD4027.

Polarity cum Continuity Tester:

With the help of this circuit, we can also identify whether the components we are using in our circuit are good or bad before mounting them on the PCB.

Reaction Timer Game Circuit:

This is a simple and funny game circuit which contains 10 LEDs that are moving in an arbitrary fashion and we must target a particular LED given by your challenger.

Multiplexer and Demultiplexer:

A multiplexer is a circuit that accepts many inputs but gives only one output whereas a demultiplexer accepts only one input and gives many outputs. Get an idea about their circuit diagram and pin diagrams in this post.

Understanding 7805 IC Voltage Regulator:

This is a circuit diagram of 7805 IC which is a 5v DC regulated IC. It is very flexible and is employed in many circuits like a voltage regulator.

Basic Logic Gates Using NAND Gate:

We are all well known that NOT, AND, OR are the basic logic gates. Here we have shown how to design these basic logic gates using one of the universal gates – NAND Gate.

Construction of Basic Logic Gates using NOR Gate:

Here, we have shown how to construct the basic logic gates – NOT, AND, OR gates using NOR Gate which is one of the universal gates.

Police Siren Circuit using NE555 Timer:

This circuit produces a sound similar to the police siren. You may also get detailed information about pin diagram and internal block diagram of the NE555 timer.

100W MOSFET Power Amplifier Circuit:

A power amplifier circuit using MOSFET has been designed to produce 100W output to drive a load of about 8 Ohms.

Digital Voltmeter Circuit using ICL7107:

Here we designed an analog to digital converter working as a digital voltmeter using a low power three and a half digit A/D converter ICL7107 having internal 7 segment decoders, display drivers, a reference and a clock.

8 Channel Quiz Buzzer Circuit using Microcontroller:

We built the circuit using a microcontroller which scans the input from push buttons and displays the corresponding number on a display device.

2 Digit Up Down Counter:

The main principle of this circuit is to increment the values on seven segment displays by pressing the button. This circuit can be mainly used in scoreboards.

Bike Turning Signal Circuit:

The objective of this circuit is to indicate left or right turn for bike/vehicle. Two identical circuits are needed, one is for left and the other is for the right. The main heart of this circuit is 555 timer.

Automatic Changeover Switch:

This is a simple automatic changeover circuit in which DC load like a series of LEDs are driven either by a battery or an AC-DC power supply.

UP/DOWN Fading LED Lights:

This is a simple up/down fading LED lights circuit which can be used in shopping malls, home, and security applications.

Police Lights using 555 Timer:

This circuit simulates the police car lights by alternate flashing. It flashes red LEDs for three times and blue LEDs for three times. This flashing action performs continuously, and this uses 555 timers and a decade counter.

PWM based DC Motor Speed Control using Microcontroller:

Here is a simple DC Motor speed control circuit designed using AVR Microcontroller. Here we use a technique called PWM (pulse width modulation) to control the speed of DC motor.

Ding Dong Sound Generator Circuit:

This is ding dong sound generator circuit is designed using 555 timer IC in astable mode. It can be used as the doorbell. With some modifications, it can be used to produce different sounds. Read this post for complete details.

PIR Sensor Based Security Alarm:

This article explains about PIR based security system in which PIR sensor is used instead of transmitter or receiver. This saves the power consumption and is low cost. This circuit can be used in the museums to protect the valuable things.

TV Remote Control Jammer:

This proposed TV jammer circuit confuses the infrared receiver in a TV by producing the constant signal that interferes the remote control signal. If you switch on the circuit once, the TV will not receive any command from the remote. This allows you to watch your own program without anyone changing the channel or volume.

Super Sensitive Intruder Alarm:

This circuit is designed to alert the user when an intruder enters into the home. If there is any obstacle in front of IR sensor, it generates an interrupt signal. This interrupt signal is given to the speaker to alert the user.

Remote Control Circuit through RF without microcontroller:

Here we have used RF434 MHz modules to make a wireless remote. Using this remote, we can control the appliances within the range of 100 meters. It is used for remote control applications like burglar alarm, car door alarm, calling bell, security systems, etc.

High and Low Voltage Cutoff with Delay and Alarm:

This high and low voltage cutoff with delay alarm circuit is an advanced automatic voltage stabilizer circuit and is used to protect our home appliances. Its cost is less as compared to voltage stabilizers.

Solar Battery Charger Circuit:

Here is a simple circuit to charge 6V, 4.5Ah rechargeable Lead-acid battery from the solar panel. This solar charger has current and voltage regulation and also has over voltage cut off facilities. This circuit may also be used to charge any battery at constant voltage because output voltage is adjustable.

Car Battery Charger Circuit:

This article aims to describe the principle of operation, design, and working of a simple car battery charger from AC mains supply and a feedback control section to control the battery charging.

Water Level Controller using 8051 Microcontroller:

In this project, we are designing the circuit which is used to detect and control the water level automatically in an overhead tank using 8051 microcontrollers. It is used in industries to control the liquid level automatically.

Dummy Alarm Circuit:

The main principle of the circuit is to flash an LED for every 5 seconds. The circuit consists of 7555 timer IC as the main component.

Reverse Parking Sensor Circuit:

If you are a new driver then it is very difficult to judge the distance while parking the car. Reverse parking sensor circuit solves this problem by indicating the distance with the help of three leds. We can easily arrange this system at the back side of the car.

Automatic LED Emergency Light Circuit:

This is the simple and cost-effective automatic emergency light circuit with light sensing. This system charges from the main supply and gets activated when the main supply is turned OFF. This emergency lamp will work for more than 8 hours.

One Transistor Electronic Code Lock System:

The main principle of this circuit is that the door lock opens only when the buttons are pressed in an order. The transistor and diode play a main role in the circuit.

Automatic Battery Charger:

This charger automatically shut off the charging process when battery attains full charge. This prevents the deep charge of the battery. If the battery voltage is below the 12V, then the circuit automatically charges the battery.

Light Activated Switch Circuit:

The main principle of this circuit is to switch ON the light when the LDR is illuminated. This circuit can be used in security applications like when there is darkness on the LDR, it stops lighting.

Remote Operated Spy Robot Circuit:

This is a simple spy robot circuit which can be controlled by the remote. The maximum controllable range is 125 meters. It is used to observe the behavior of wild animals where human beings cannot reach.

Digital Voltmeter using 8051 Microcontroller:

This is a simple digital voltmeter circuit designed using 8051 microcontrollers. This circuit measures the input voltage from 0V to 5V. Here, the input voltage should be DC voltage to get the accurate output on LCD.

Ultrasonic Rangefinder using 8051:

This circuit explains to you how to measure the distance using 8051 microcontrollers. This ultrasonic rangefinder system measures the distance up to 2.5 meters at the accuracy of 1 cm.

Stepper Motor Interfacing with 8051 Microcontroller:

The main principle of this circuit is to rotate the stepper motor stepwise at a particular step angle. The ULN2003 IC is used to drive the stepper motor as the controller cannot provide the current required by the motor.

Frequency Counter Circuit:

Here we design a simple frequency counter system using two timers and two counters. While one of the Timer IC is used to produce clock signals, the other is used to produce the time limited signal of one second.

Delay using 8051 Timers:

In this project, about timers in 8051 microcontrollers and how to generate a delay using 8051 timers.

Interfacing 7 Segment Display to 8051:

This article describes you how to interface seven segments to the AT89C51 microcontroller. This system displays the digits from 0 to 9 continuously with a predefined delay.

LC Meter using 555 Timer:

This is a simple LC Meter circuit designed using 555 Timer and 8051 microcontrollers. It is mainly used to measure the value of a reactive element like a capacitor or an inductor.

TV Transmitter Circuit:

The main principle of this circuit is to transmit the audio and video signals. Here audio signals are frequency modulated and video signals are PAL modulated. These modulated signals are applied for the antenna.

DC Motor Interfacing with 8051 Microcontroller:

Here is a simple but very useful circuit in our real life named interfacing DC motor with 8051 microcontrollers. It describes you how to control the DC motor using the AT89C51 controller.

Stun Gun Circuit:

This Stun gun circuit is mostly used as a weapon to stun or send shock waves to the target with the intention to weaken or paralyze it.

Transistor Intercom Circuit:

This transistor intercom circuit is a simple two-way intercom circuit which is used for the dual purpose of sending as well as receiving signals.

LED Interfacing with 8051:

The main principle of this circuit is to interface LEDs to the 8051 family microcontroller. Commonly, used LEDs will have a voltage drop of 1.7v and current of 10mA to glow at full intensity. This is applied through the output pin of the microcontroller.

Wailing Siren Circuit:

The main principle of this circuit is to produce a wailing siren. The 555 timer IC is operated in a stable mode. When the switch is pressed, the speaker produces high pitch siren and when it is released, its pitch decreases and is switched off after 30 seconds.

Audio Tone Control Circuit:

This article explains to you how to design an audio tone control circuit with the gain of around 25. This design needs less number of components and it is cost effective.

FM Remote Encoder/Decoder Circuit:

This is a simple post which shows you how to design FM remote encoder and decoder circuit using RF600E and RF600D ICs. This pair of encoder and decoder ICs establishes the communication with high-level security. The operating voltage of these ICs is from 2V to 6.6V DC.

Wireless Mobile Battery Charger Circuit:

This circuit mainly works on the principle of mutual inductance. This circuit may be used as wireless power transfer circuit, a wireless mobile charger circuit, wireless battery charger circuit, etc.

Battery Level Indicator:

This article explains to you how to design battery level indicator. You can use this circuit to check car battery or inverter. So by using this circuit, we can increase the lifetime of the battery.

FM Radio Circuit:

FM Radio circuit is the simple circuit that can be tuned to the required frequency locally. This article describes the circuit of the FM radio circuit. This is a pocket-sized radio circuit.

LED Lamp Circuit using USB Port:

This is a simple USB LED Light circuit which produces an output of 5v. It may be used as an emergency light and also as a reading lamp.

Interfacing GPS with 8051 Microcontroller:

In this interfacing of GPS with 8051 circuits, GPS module calculates the position by reading the signals that are transmitted by satellites.

How to Interface Real Time Clock with PIC18F:

Get an idea about RTC, PIC Microcontroller pin diagram and how to interface RTC with PIC18F. RTC is an integrated circuit which keeps track of current time.

Random Number Generator using 8051:

This circuit helps to generate a random number in between 0 to 100 when the push button is pressed and it may be used in the games like monopoly, snake ladder.

Active Audio Crossover Circuit:

Audio crossover is an electronic filter used in audio applications to send the appropriate signal to the speakers or drivers. This circuit is used in HiFi audio systems to separate the frequency bands from the audio signal.

IR Audio Link Circuit:

This simple IR audio link circuit is used to transmit audio signals wirelessly. This IR audio link is able to transmit audio signals up to 4 meters.

Cell Phone Controlled Home Appliances:

This mobile controlled home automation system is designed without using a microcontroller. We can also control a robot using this technology by making some modifications.

Variable Voltage Power Supply:

This helps to design a variable power supply circuit which will provide 0 to 28V at 6 to 8 amps. It can be used in various power amplifiers and oscillators to provide DC supply.

Digital Clock using 8051:

This circuit displays the time on LCD. For this clock, we can set the time at any instant. Here the clock works in 24-hour mode and the RTC chip is configured by programming 8051 controllers.

GSM Interfacing with 8051:

The main principle of this circuit is to interface a GSM modem with the microcontroller. The microcontroller used is an AT89C51 microcontroller.

Multi-Channel Audio Mixer Circuit:

This audio mixing circuit has 2 MIC inputs and 2-line inputs. If you want to increase the input channels according to the application, then add same circuit in parallel with the existing circuit.

Puff to OFF LED Circuit:

The main principle of the circuit is to turn off the LED by a puff. The puff applied to the mic is converted into a voltage whose value is very small. This voltage is amplified and applied to the circuit in order to make the led turn off.

Biometric Attendance System:

The main aim of this circuit is to take the attendance using the biometric method and display when requested. This can be used in educational institutions, industries, etc.

Light Activated Alarm Circuit:

The main principle of this circuit is to produce sound depending on the light intensity falling on the circuit. As the light intensity falling on the circuit increases, it produces pulses with more duration and thus producing more sound. The main part of the circuit is 555 timer IC.

Electronic Eye Controlled Security System:

This is a simple electronic eye controlled security system circuit designed using 7805 voltage regulator and LDR. It is used in security applications.

USB Sound Card Circuit:

This USB sound card circuit is a device which allows an embedded system to create and record real and high-quality sound. Read this post for more details.

10 LED VU Meter Circuit:

VU Meters are used in many applications like discotheques to measure the level of audio signals. Here is the circuit diagram and working of LED VU Meter.

Hi-Fi Dx Bass Circuit:

This Hi-Fi Dx Bass Circuit describes the design, principle, and operation of a two-stage bass boosting circuit using simple high and low pass filters.

Wireless Electronic Notice Board using GSM:

This wireless electronic notice board using GSM Technology and microcontroller circuit is used to display the data on LCD whatever we sent from the mobile.

Password Based Door Lock System using 8051 Microcontroller:

This system demonstrates a password-based door lock system wherein once the correct code or password is entered, the door is opened and the concerned person is allowed access to the secured area. After some time, the door would be closed automatically. It is fully functional based on the password.

Cell Phone Controlled Robotic Vehicle:

Cell phone controlled the robotic vehicle based on DTMF controller. This is without using the microcontroller. The object will be functional through a cell phone. It can be used in industries and surveillance systems.

Human Detection Robot using 8051 Microcontroller:

The main principle of the circuit is to detect the human using the human detection sensor. The wireless robot is operated manually using PC. The wireless technology used here is Radio Frequency technology. The data is transmitted to the receiver through RF.

SMS Controlled Robot:

GSM controlled robot or SMS controlled robot is a wireless robot which performs the necessary actions by receiving a set of instructions in the form a Short Message Service (SMS).

Remote Password Operated Electronic Home Appliances:

How to control the electrical appliances using an Android device. Here, Bluetooth module is interfaced to 8051 microcontrollers. This Bluetooth receives the commands from the Android application device using wireless communication.

Automatic Room Lights using Arduino and PIR Sensor:

This is a very simple lights project on automatic room lights, where Arduino and PIR sensor automatically turn on and off the room lights.

Automatic Door Opener System using PIR Sensor and Arduino:

In this project, an Arduino and PIR Sensor based Automatic Door Opener System is implemented, whereupon detecting any human movement, the door opens automatically. Mostly we see these kinds of functionality at shopping malls.

DIY RGB LED Matrix:

This is a simple led matrix project through control it is using an android application. This project can be useful in making sign boards, scrolling message boards, etc.

Arduino 8×8 LED Matrix Interface:

This project similar to above project but using Arduino with more LEDs. It shows you how to interface an 8×8 LED Matrix to Arduino. There is a dedicated Android App for this project that you can install and control the 8×8 LED Matrix from a Phone.

Arduino DC Motor Control using L298N:

Using this project, you can control a simple DC Motor using the very popular L298N Motor Driver Module and Arduino. You can control two DC Motors at a time.

DIY Arduino and Bluetooth Controlled Robotic Arm Project:

Very interesting project for who are interested in robotics too. You can build your own robotic arm using the data from this project. This is based on Arduino, Bluetooth and 3d printed robotic arm parts. The main key element is we have used an android mobile application to control this robotic arm.

DIY Arduino Christmas Tree Lights using LEDs:

This is a seasonal project, we can use this kind of project for any special occasion. A holiday-themed project where we will be using an Arduino board to control the led lights arranged on a Christmas tree.

Hand Gesture Controlled Robot using Arduino:

One more interesting project, a simple hand gesture based robotic vehicle is designed. it is designed using Arduino, mpu6050, and rf transmitter-receiver pair.

Obstacle Avoiding Robot using Arduino:

We made this project using Arduino. Obstacle avoiding robot can run continuously without hitting any obstacle. Its based on Arduino. We have used an ultrasonic sensor in this project to detect the obstacles.

Heartbeat Sensor using Arduino:

A heart rate monitoring system is designed in this project by using Arduino, also we have included a sensor to detect the heartbeat. it is a very simple and effective project where the result can be viewed on an LCD display.

DIY LED Light Bulb (LED Lamp):

This is a simple project, you can do it yourself. we will show you how to make your own LED Lamp using simple hardware. It is based on the transformerless power supply.

Metal Detector Robotic Vehicle:

This is one more interesting and useful project. Landmines buried under the ground causes a threat to the lives and affect the economy of the nation. Detection and removing of these mines manually is a dangerous task. So, we use a metal detection robot which works on RF technology.

Sun Tracking Solar Panel:

This project describes circuit that rotates solar panel. A Sun tracking solar panel consists of two LDRs, solar panel, stepper motor, and ATMEGA8 Microcontroller.

Speed Control of DC Motor Using Pulse Width Modulation:

This pulse width modulation technique is the more efficient way to proceed to manage the speed of our DC motor manually.

Water Level Alarm Using 555 Timer:

This is a similar project we have done already but here we are using different module 555 timer circuit. Very simple and low-cost hardware project. The aim of this project is to design a water level detecting alarm with simple and low-cost hardware without compromising on the performance of the device.

Bidirectional Visitor Counter using 8051:

It is helpful to count the number of persons entering or leaving a room and to display it on a screen. Mostly useful at movie place, shopping malls etc.

Temperature Controlled DC Fan using Microcontroller:

The main principle of the circuit is to switch on the fan connected to DC motor when the temperature is greater than a threshold value. This can be used in home applications and in CPU to reduce heat.

Password-based Circuit Breaker:

This password-based circuit breaker project is built using the 8051 controllers and is used to switch off the power supply to the line by entering a password.

Auto Intensity Control of Street Lights:

This is a simple circuit that automatically controls the intensity of street lights which is designed using microcontroller and LEDs.

Line Following Robotic Circuit using ATMega8 Microcontroller:

This line follower robot is a basic robot that follows a specific path indicated by a line having some particular width.

Digital Tachometer using 8051 Microcontroller:

Here we designed a simple non-contact tachometer using the microcontroller which can measure speed with an accuracy of 1 rev/sec.

5 Channel IR Remote Control System using Microcontroller:

This article is aimed to design and demonstrate a simple 5 channel remote control system to drive five loads. This circuit works on the principle of IR communication.

Bipolar LED Driver Circuit:

This bipolar LED driver circuit is very useful at the places where flashing of light is required, as in beacon flashing. This circuit can be mainly used for indication purposes.

Celsius Scale Thermometer using AT89C51:

This Celsius Scale Thermometer circuit is designed using at89c51 and lm35. This circuit works on analog to digital conversion principle. It can be used at homes, mobile places like cars to keep a track of the temperature.

Density Based Traffic Signal System using Microcontroller:

In this system, we use IR sensors to measure the traffic density. We must arrange one IR sensor for each road, these sensors always sense the traffic on that particular road. All these sensors are interfaced to the microcontroller. Based on these sensors, the controller detects the traffic and controls the traffic system.

Automatic Washroom Light Switch:

This is a simple but very useful circuit in our real life which helps to automatically turn On the lights when a person enters the washroom and it automatically turns Off the lights when he leaves it.

Automatic Door Bell with Object Detection:

This automatic doorbell with object detection circuit helps to sense the presence of a person or an object automatically and rings the doorbell.

Boolean Algebra Calculator:

This Boolean algebra calculator is an interesting project which is more useful in our real life by working as a portable calculator to simplify the Boolean expression on the fly. In our circuit, we use Boolean algebra simplification methods like the Quine-McCluskey algorithm to simplify the Boolean expression and display the output on the display.

Auto Night Lamp using High Power LED:

This Auto Night Lamp is an interesting circuit which helps to turn ON the LED lights interfaced to it at night time and it turns OFF the lights automatically when it is the day.

Mobile Jammer Circuit:

This circuit is used to block the signals of cell phones within the range of 100 meters. This circuit can be used in TV transmission and for remote controlled toys or playthings.

Unbiased Digital Dice with LEDs:

This is a circuit diagram of digital dice which is nearly unbiased. By using this circuit, there is no chance to cheat as the circuit operates at such a high speed that the circuit is almost imperceptible to the human eye.

Metal Detector Circuit:

This is a simple metal detector circuit which is very useful for checking the person in shopping malls, hotels, cinema halls to ensure that person is not carrying any explosive metals or illegal things like guns, bombs etc.

Panic Alarm:

This panic alarm circuit helps us to intimate others regarding our bad situation without any delay. It is more useful when an intruder entering our house or bad health status at which we are unable to intimate to the people around us.

Automatic Railway Gate Controller with High-Speed Alerting System:

The main aim of this project is to operate and control the unmanned railway gate in the proper manner in order to avoid the accidents in the unmanned railway crossing.

LED Flasher Circuit:

LED Flasher is a simple circuit which will blink the LEDs in the regular time period. This circuit can be used for decoration purpose or can be used for a signaling purpose and many more.

Dancing Bi-Color LED Lights Circuit:

Generally, we use small voltage bulbs in the dancing bulbs. This circuit is mainly used on the occasions, pubs, decoration articles or in visual indication sign boards etc. Here in this project, we have used a bi-color LEDs for sequential running light.

Intelligent Unambiguous Night Lamp Switcher:

This is the circuit diagram of unambiguous night lamp switch, which turns ON our domestic lights automatically when it is dark, without human interference. It also avoids repeated frequent switching of the devices which is usually ignored in most similar circuits but may have a detrimental effect on our operating devices.

Thermistor Temperature Sensing Alarm:

This circuit is a temperature sensing as well as alarm circuit. The circuit raises an alarm whenever the temperature crosses a certain limit.

Pull Pin Security Alarm System:

This circuit helps us to get alerted when anybody picks our pockets or bags. The circuit is very helpful to prevent our goods getting pickpocketed.

Auto Turn Off Soldering Iron Circuit:

This circuit helps the soldering iron to turn off automatically when it detects overheating and thereby avoids it from getting damaged.

Remote Operated Alarm Circuit:

This circuit rings an alarm when you point a TV remote at it and press on any button. This can be used as a calling bell to call your assistant.

Battery Charger Circuit Using SCR:

Here is the circuit diagram of battery charger circuit using Silicon Controlled Rectifier. SCR can be used in half wave rectifier, full wave rectifier, inverter circuits, power control circuits, etc.

FM Bugger Circuit:

Here is a small circuit with which you can listen to other people conversation from long distance using the normal FM radio set. This FM bugger circuit is kept in the room where you want to listen to the conversation. You can listen to this conversation using the normal FM radio set.

Cell Phone Detector:

This is a simple circuit which helps to detect the presence of an activated cell phone by detecting the signals in the frequency range of 0.9 to 3GHz. It helps in mobile phones tracking which are used for spying.

Battery Powered Portable Light:

This circuit is more helpful in handling unexpected and undesired darkness in our homes or offices. It provides a considerable amount of brightness required to do our daily tasks.

IR Remote Control Switch:

By using this circuit, we can control any household appliance with the help of remote. In this project, there are two parts– one is in the transmitting section and the other is in the receiving section. Receiving section will be in a stable position which is connected to any load and transmitter will act like a normal remote.

Continuity Tester with Melody:

This circuit works as a continuity tester device which tests the continuity of the wire at hand. It is an indispensable tool to check broken wires and undesired shorting of wires.

Rain Alarm Circuit:

Rainwater detector will detect the rain and make an alert; rainwater detector is used in the irrigation field, home automation, communication, automobiles etc. Here is the simple and reliable circuit of rainwater detector which can be constructed at low cost.

Automatic Plant Irrigation System:

This project circuit is more useful in watering plants automatically without any human interference. It is more useful when the owner is not present in the home for a few days.

Hot Water Geyser Controller Circuit:

This circuit is made to turn OFF geysers as soon as our water gets hot and are ready for bathing.

Lead Acid Battery Charger Circuit:

Lead Battery is a rechargeable battery and is more useful in our real life as it will dissipate very little energy, it has the very low energy to weight ratio, it can deliver high current, can work for a long time with high efficiency and is very low cost.

Motion Detector Circuit:

The motion detector is not only used as intruder alarm but also used in many applications like home automation system, energy efficiency system, etc. The motion detector will detect the motion of the people or objects and give the appropriate output according to the circuit.

Touch ON and OFF Switch Circuit:

This Touch ON/OFF Switch circuit is more useful in such a way that we can automatically ON or OFF any switch by touching a device without moving from our place.

USB Mobile Charger Circuit:

This circuit is useful in charging the mobiles through USB outlet present in our laptops and PCs. For the charging of your mobile phone, this circuit provides you a regulated voltage of 4.7 volts.

Security Alarm Circuit:

This circuit helps you to guard your precious documents as well as jeweler from intruders or theft. All you need is to just place this circuit in front of the locker or below the mat so when an unknown person come and walk over the switch, the circuit will trigger, and the sound of alarm comes.

Mosquito Repellent Circuit:

Here is the simple electronic mosquito repellent circuit which can produce ultrasound in the frequency range of 20-38 kHz, which can scare away mosquitoes.

Simple FM Radio Jammer Circuit:

This is a Jammer circuit which is used to block the signals. Jammer circuit produces the high-frequency signal which will confuse the receiver of a particular system from receiving the signal, even though the circuit is working properly, the user of the system feels that the circuit is not working properly.

Automatic Street Light Controller Circuit Using Relays and LDR:

This circuit helps in automatically turn ON/OFF the street lights using relays and LDR. The whole circuit is based on IC CA3140.

Battery Charger Circuit:

This battery charger circuit works on the principle of controlling switching of an SCR based on charging and discharging of the battery.

Interfacing 16×2 LCD with 8051:

This is a simple circuit diagram which helps to describe interfacing of 16X2 LCD module to AT89C51 which is an 8051 family microcontroller.

PWM LED Dimmer Using NE555:

The Pulse Width Modulation (PWM) plays an important role in controlling the circuits. We use this PWM to dim the intensity of light of the LED.

Simple Fire Alarm Circuits:

Here are two simple fire alarm circuits which are used to detect the fire automatically and inform to the people immediately with an alarm.

Wireless Switch Circuit using CD4027:

This is a simple circuit which needs no physical contact with the appliance. In this circuit, all you need is to pass your hand above LDR to ON or OFF the switch.

Electronic Letter Box:

This is a simple circuit which helps in finding out any letter dropped in our box by stopping the LED lights attached in this circuit.

Clap Switch Circuit for Devices:

This is another simple but very useful circuit which helps to ON or OFF a device without moving from your place and helps to control the speed of the electric devices like a fan, etc.

12v DC to 220v AC Converter Circuit:

Here is a simple voltage is driven inverter circuit which converts 12v DC signal to single phase 220v AC using power transistors as a switching device.

FM Transmitter Circuit:

Here we built a wireless FM transmitter which uses RF communication to transmit the medium or low power FM signal. The maximum range of transmission is around 2 km.

100w Subwoofer Amplifier Circuit:

Here is the circuit diagram and working of 100w subwoofer amplifier circuit. A Subwoofer is a loudspeaker which produces audio signals of low frequencies.

DTMF Based Home Automation System Circuit:

This is a simple and very useful circuit in our real life named DTMF controlled home appliances system. It helps to control the home appliances using DTMF technology.

Street Lights that Glow on Detecting Vehicle Movement:

This article describes the circuit that switches the street lights on detecting vehicle movement and remains off after fixed time. This system controls the street lights using the light dependent resistor and PIR sensor.

555 Timer IC Testing Circuit:

This is a simple 555 IC testing-circuit which tests your entire 555 timer IC. So before using your IC, you may check whether your IC is good or bad by using this circuit.

Curtain Opener/Closer Circuit:

This circuit will open and close the curtain of your home and office just by pushing a switch. So, with the help of this unique circuit, we do not need to move from one place to open and close the curtain.

Variable Power Supply and Charger:

This is a circuit which helps to check or test your electronic projects and also to charge the Mobile phone batteries. This circuit can also work as an emergency light.

LED Running Lights Circuit:

This is a simple circuit consists of 9 LED lights in knight rider scanner mode. It will present an eye-catching look as the LED initially travel in the one way and then travel reverse in the similar direction.

Luggage Security Alarm:

This is a simple alarm circuit which helps in ringing a warning alarm when someone tries to steal the luggage.

9 Way Clap Switch Circuit:

This circuit helps you to manage your appliances in your home by just clap without moving from your bed.

12V to 24V DC Converter Circuit:

This is another kind of circuit which helps to convert 12V DC current to 24V DC current.

230V LED Driver:

Here we design a simple circuit driving a series of LED from 230V AC. This is accomplished using a capacitor-based power supply. This is a low cost and efficient circuit and can be used at homes.

3X3X3 LED Cube:

This is a simple a simple LED cube circuit designed without using the microcontroller. It is based on the principle of driving LEDs using the clock pulses.

Monostable Multivibrator Circuit Operation:

Here is the monostable multivibrator circuit diagram and working. The multivibrator is an electronic circuit which will work as two-stage amplifier operating in both stable and a stable mode.

Interfacing 16X2 LCD with PIC Microcontroller:

This is a circuit which helps in interfacing 16Ã —2 LCD to PIC18F4550 microcontroller which is of family PIC18F.

Morse Code Generator Circuit:

This is a circuit used to generate morse code. Morse code is very old and versatile technique to send text messages using wireless media.

555 Timer in Monostable Multivibrator Mode:

The circuit is triggered by a falling edge, that is, by a sudden transition from HIGH to LOW. The trigger pulse, produced by pressing the button, must be of shorter duration than the intended output pulse.

555 Timer as an Astable Multivibrator:

In this circuit, there are three resistors named R inside it and all have equal values. These form a voltage divider having reference voltages of 1/3 and 2/3 of Vcc (the power supply). The logic state of the flip-flop is controlled by the reference voltage which is given to one of the inputs of both two comparators.

Mains Operated LED Light Circuit:

This is a simple circuit which is more useful to save our resources, energy, and money by installing in your homes.

LED Lamp Dimmer Circuit:

In this circuit, at the starting LED glows slowly, then grown brighter and once again slowly it became dim. The basis of the whole circuit is an operational amplifier IC named LM358.

Variable Voltage Power Supply from Fixed Voltage Regulator:

This Voltage regulator circuit is used to get fixed voltage at the output without depending on the input voltage.

LED Christmas Lights Circuit:

This is a simple circuit used to decorate your house by building Christmas lights using LEDs. The lights will get ON at night and OFF in morning time.

Audio Equalizer Circuit:

The circuit is used to change the tune/melody into a different pitch level by devoid of loss in the tune. It is mainly useful to music lovers.

Air Flow Detector Circuit:

This air flow detector circuit can be used to detect the flow of air in areas like the car engine. It can also be used as the temperature detector.

150W Power Amplifier Circuit:

Here we designed a power amplifier circuit using push-pull class AB configuration to derive a power of 150W to drive a load of 8 Ohms (speaker).

7 Segment LED Display Decoder:

This is the circuit diagram of display decoder which is used to convert a BCD or binary code into a 7 segment code used to operate a 7 segment LED display.

Digital Temperature Sensor:

The main principle of this circuit is to display the digital temperature value. These are mainly used in environmental applications.

Digital Stopwatch Circuit:

This is a simple circuit that displays count from 0 to 59, representing a 60 second time interval. It consists of a 555 timer to produce the clock pulses and two counter ICs to carry out the counting operation.

Toy Organ using 555 Timer IC:

This is the circuit diagram of simple Toy Piano using 555 Timer IC. It produces different tones or sounds depending on the frequency range.

RFID based Attendance System:

This simple RFID based attendance system is designed using ATmega8 Microcontroller and is mainly used in educational institutions, industries, etc. where authentication is needed.

Low Power Audio Amplifier using 555 Timer:

This is a simple low power audio amplification circuit designed using 555 timers. It can be used to develop low power music systems used in vehicles.

Interfacing 16X2 LCD to AVR Microcontroller:

This is a circuit which helps in interfacing 16X2 LCD with AVR Microcontroller. The Atmega16 belongs to the AVR microcontroller family.

SR Flip Flop with NAND and NOR Gates:

SR Flip Flop, also known as SR latch is the most vital as well as broadly used Flip Flop. Get an idea about the design of SR Flip Flop with NAND and NOR Gates.

JK Flip Flop using CD4027:

CD4027 is a JK flip-flop that is generally used for data storing. Get an idea about how to build JK Flip Flop with CD4027.

Polarity cum Continuity Tester:

With the help of this circuit, we can also identify whether the components we are using in our circuit are good or bad before mounting them on the PCB.

Reaction Timer Game Circuit:

This is a simple and funny game circuit which contains 10 LEDs that are moving in an arbitrary fashion and we must target a particular LED given by your challenger.

Multiplexer and Demultiplexer:

A multiplexer is a circuit that accepts many inputs but gives only one output whereas a demultiplexer accepts only one input and gives many outputs. Get an idea about their circuit diagram and pin diagrams in this post.

Understanding 7805 IC Voltage Regulator:

This is a circuit diagram of 7805 IC which is a 5v DC regulated IC. It is very flexible and is employed in many circuits like a voltage regulator.

Basic Logic Gates Using NAND Gate:

We are all well known that NOT, AND, OR are the basic logic gates. Here we have shown how to design these basic logic gates using one of the universal gates – NAND Gate.

Construction of Basic Logic Gates using NOR Gate:

Here, we have shown how to construct the basic logic gates – NOT, AND, OR gates using NOR Gate which is one of the universal gates.

Police Siren Circuit using NE555 Timer:

This circuit produces a sound similar to the police siren. You may also get detailed information about pin diagram and internal block diagram of the NE555 timer.

100W MOSFET Power Amplifier Circuit:

A power amplifier circuit using MOSFET has been designed to produce 100W output to drive a load of about 8 Ohms.

Digital Voltmeter Circuit using ICL7107:

Here we designed an analog to digital converter working as a digital voltmeter using a low power three and a half digit A/D converter ICL7107 having internal 7 segment decoders, display drivers, a reference and a clock.

8 Channel Quiz Buzzer Circuit using Microcontroller:

We built the circuit using a microcontroller which scans the input from push buttons and displays the corresponding number on a display device.

2 Digit Up Down Counter:

The main principle of this circuit is to increment the values on seven segment displays by pressing the button. This circuit can be mainly used in scoreboards.

Bike Turning Signal Circuit:

The objective of this circuit is to indicate left or right turn for bike/vehicle. Two identical circuits are needed, one is for left and the other is for right. The main heart of this circuit is 555 timer.

Automatic Changeover Switch:

This is a simple automatic changeover circuit in which DC load like a series of LEDs are driven either by a battery or an AC-DC power supply.

UP/DOWN Fading LED Lights:

This is a simple up/down fading LED lights circuit which can be used in shopping malls, home, and security applications.

Police Lights using 555 Timer:

This circuit simulates the police car lights by alternate flashing. It flashes red LEDs for three times and blue LEDs for three times. This flashing action performs continuously, and this uses 555 timers and a decade counter.

PWM based DC Motor Speed Control using Microcontroller:

Here is a simple DC Motor speed control circuit designed using AVR Microcontroller. Here we use a technique called PWM (pulse width modulation) to control the speed of DC motor.

Ding Dong Sound Generator Circuit:

This is ding dong sound generator circuit is designed using 555 timer IC in astable mode. It can be used as the doorbell. With some modifications, it can be used to produce different sounds. Read this post for complete details.

PIR Sensor Based Security Alarm:

This article explains about PIR based security system in which PIR sensor is used instead of transmitter or receiver. This saves the power consumption and is low cost. This circuit can be used in the museums to protect the valuable things.

TV Remote Control Jammer:

This proposed TV jammer circuit confuses the infrared receiver in a TV by producing the constant signal that interferes the remote control signal. If you switch on the circuit once, the TV will not receive any command from the remote. This allows you to watch your own program without anyone changing the channel or volume.

Super Sensitive Intruder Alarm:

This circuit is designed to alert the user when an intruder enters into the home. If there is any obstacle in front of the IR sensor, it generates an interrupt signal. This interrupt signal is given to the speaker to alert the user.

Remote Control Circuit through RF without microcontroller:

Here we have used RF434 MHz modules to make the wireless remote. Using this remote, we can control the appliances within the range of 100 meters. It is used for remote control applications like burglar alarm, car door alarm, calling bell, security systems, etc.

High and Low Voltage Cutoff with Delay and Alarm:

This high and low voltage cutoff with delay alarm circuit is an advanced automatic voltage stabilizer circuit and is used to protect our home appliances. Its cost is less as compared to voltage stabilizers.

Solar Battery Charger Circuit:

Here is a simple circuit to charge 6V, 4.5Ah rechargeable Lead-acid battery from the solar panel. This solar charger has current and voltage regulation and also has over voltage cut off facilities. This circuit may also be used to charge any battery at constant voltage because the output voltage is adjustable.

Car Battery Charger Circuit:

This article aims to describe the principle of operation, design, and working of a simple car battery charger from AC mains supply and a feedback control section to control the battery charging.

Water Level Controller using 8051 Microcontroller:

In this project, we are designing the circuit which is used to detect and control the water level automatically in the overhead tank using 8051 microcontrollers. It is used in industries to control the liquid level automatically.

Dummy Alarm Circuit:

The main principle of the circuit is to flash an LED for every 5 seconds. The circuit consists of 7555 timer IC as the main component.

Reverse Parking Sensor Circuit:

If you are a new driver then it is very difficult to judge the distance while parking the car. Reverse parking sensor circuit solves this problem by indicating the distance with the help of three LED’s. We can easily arrange this system at the back side of the car.

Automatic LED Emergency Light Circuit:

This is the simple and cost-effective automatic emergency light circuit with light sensing. This system charges from the main supply and gets activated when the main supply is turned OFF. This emergency lamp will work for more than 8 hours.

One Transistor Electronic Code Lock System:

The main principle of this circuit is that the door lock opens only when the buttons are pressed in an order. The transistor and diode play a main role in the circuit.

Automatic Battery Charger:

This charger automatically shut off the charging process when battery attains full charge. This prevents the deep charge of the battery. If the battery voltage is below the 12V, then the circuit automatically charges the battery.

Light Activated Switch Circuit:

The main principle of this circuit is to switch ON the light when the LDR is illuminated. This circuit can be used in security applications like when there is darkness on the LDR, it stops lighting.

Remote Operated Spy Robot Circuit:

This is a simple spy robot circuit which can be controlled by the remote. The maximum controllable range is 125 meters. It is used to observe the behavior of wild animals where human beings cannot reach.

Digital Voltmeter using 8051 Microcontroller:

This is a simple digital voltmeter circuit designed using 8051 microcontrollers. This circuit measures the input voltage from 0V to 5V. Here, the input voltage should be DC voltage to get the accurate output on LCD.

Ultrasonic Rangefinder using 8051:

This circuit explains to you how to measure the distance using 8051 microcontrollers. This ultrasonic rangefinder system measures the distance up to 2.5 meters at the accuracy of 1 cm.

Stepper Motor Interfacing with 8051 Microcontroller:

The main principle of this circuit is to rotate the stepper motor stepwise at a particular step angle. The ULN2003 IC is used to drive the stepper motor as the controller cannot provide the current required by the motor.

Frequency Counter Circuit:

Here we design a simple frequency counter system using two timers and two counters. While one of the Timer IC is used to produce clock signals, the other is used to produce the time limited signal of one second.

Delay using 8051 Timers:

In this project, about timers in 8051 microcontrollers and how to generate a delay using 8051 timers.

Interfacing 7 Segment Display to 8051:

This article describes you how to interface seven segments to AT89C51 microcontroller. This system displays the digits from 0 to 9 continuously with a predefined delay.

LC Meter using 555 Timer:

This is a simple LC Meter circuit designed using 555 Timer and 8051 microcontrollers. It is mainly used to measure a value of a reactive element like a capacitor or an inductor.

TV Transmitter Circuit:

The main principle of this circuit is to transmit the audio and video signals. Here audio signals are frequency modulated and video signals are PAL modulated. These modulated signals are applied for the antenna.

DC Motor Interfacing with 8051 Microcontroller:

Here is a simple but very useful circuit in our real life named interfacing DC motor with 8051 microcontrollers. It describes you how to control the DC motor using the AT89C51 controller.

Stun Gun Circuit:

This Stun gun circuit is mostly used as a weapon to stun or send shock waves to the target with the intention to weaken or paralyze it.

Transistor Intercom Circuit:

This transistor intercom circuit is a simple two-way intercom circuit which is used for the dual purpose of sending as well as receiving signals.

LED Interfacing with 8051:

The main principle of this circuit is to interface LEDs to the 8051 family microcontroller. Commonly, used LEDs will have the voltage drop of 1.7v and current of 10mA to glow at full intensity. This is applied through the output pin of the microcontroller.

Wailing Siren Circuit:

The main principle of this circuit is to produce a wailing siren. The 555 timer IC is operated in a stable mode. When the switch is pressed, the speaker produces high pitch siren and when it is released, its pitch decreases and is switched off after 30 seconds.

Audio Tone Control Circuit:

This article explains to you how to design an audio tone control circuit with the gain of around 25. This design needs less number of components and it is cost effective.

FM Remote Encoder/Decoder Circuit:

This is a simple post which shows you how to design FM remote encoder and decoder circuit using RF600E and RF600D ICs. This pair of encoder and decoder ICs establishes the communication with high-level security. The operating voltage of these ICs is from 2V to 6.6V DC.

Wireless Mobile Battery Charger Circuit:

This circuit mainly works on the principle of mutual inductance. This circuit may be used as wireless power transfer circuit, the wireless mobile charger circuit, wireless battery charger circuit, etc.

Battery Level Indicator:

This article explains to you how to design battery level indicator. You can use this circuit to check car battery or inverter. So by using this circuit, we can increase the lifetime of a battery.

FM Radio Circuit:

FM Radio circuit is the simple circuit that can be tuned to the required frequency locally. This article describes the circuit of the FM radio circuit. This is a pocket-sized radio circuit.

LED Lamp Circuit using USB Port:

This is a simple USB LED Light circuit which produces an output of 5v. It may be used as an emergency light and also as a reading lamp.

Interfacing GPS with 8051 Microcontroller:

In this interfacing of GPS with 8051 circuits, GPS module calculates the position by reading the signals that are transmitted by satellites.

How to Interface Real Time Clock with PIC18F:

Get an idea about RTC, PIC Microcontroller pin diagram and how to interface RTC with PIC18F. RTC is an integrated circuit which keeps track of current time.

Random Number Generator using 8051:

This circuit helps to generate a random number in between 0 to 100 when the push button is pressed and it may be used in the games like monopoly, snake ladder.

Active Audio Crossover Circuit:

Audio crossover is an electronic filter used in audio applications to send the appropriate signal to the speakers or drivers. This circuit is used in HiFi audio systems to separate the frequency bands from the audio signal.

IR Audio Link Circuit:

This simple IR audio link circuit is used to transmit audio signals wirelessly. This IR audio link is able to transmit audio signals up to 4 meters.

Cell Phone Controlled Home Appliances:

This mobile controlled home automation system is designed without using the microcontroller. We can also control a robot using this technology by making some modifications.

Variable Voltage Power Supply:

This helps to design a variable power supply circuit which will provide 0 to 28V at 6 to 8 amps. It can be used in various power amplifiers and oscillators to provide DC supply.

Digital Clock using 8051:

This circuit displays the time on LCD. For this clock, we can set the time at any instant. Here the clock works in 24-hour mode and the RTC chip is configured by programming 8051 controllers.

GSM Interfacing with 8051:

The main principle of this circuit is to interface a GSM modem with the microcontroller. The microcontroller used is AT89C51 microcontroller.

Multi-Channel Audio Mixer Circuit:

This audio mixing circuit has 2 MIC inputs and 2-line inputs. If you want to increase the input channels according to the application, then add the same circuit in parallel with the existing circuit.

Puff to OFF LED Circuit:

The main principle of the circuit is to turn off the LED by a puff. The puff applied to the mic is converted into a voltage whose value is very small. This voltage is amplified and applied to the circuit in order to make the led turn off.

Biometric Attendance System:

The main aim of this circuit is to take the attendance using the biometric method and display when requested. This can be used in educational institutions, industries, etc.

Light Activated Alarm Circuit:

The main principle of this circuit is to produce sound depending on the light intensity falling on the circuit. As the light intensity falling on the circuit increases, it produces pulses with more duration and thus producing more sound. The main part of the circuit is 555 timer IC.

Electronic Eye Controlled Security System:

This is a simple electronic eye controlled security system circuit designed using 7805 voltage regulator and LDR. It is used in security applications.

USB Sound Card Circuit:

This USB sound card circuit is a device which allows an embedded system to create and record real and high-quality sound. Read this post for more details.

10 LED VU Meter Circuit:

VU Meters are used in many applications like discotheques to measure the level of audio signals. Here is the circuit diagram and working of LED VU Meter.

Hi-Fi Dx Bass Circuit:

This Hi-Fi Dx Bass Circuit describes the design, principle, and operation of a two-stage bass boosting circuit using simple high and low pass filters.

This content was originally published here.

LCD Monitor Repair

Check Also

Temperature Monitoring on Cayenne IoT Platform | Full Electronics Project

This temperature monitoring system is based on Cayenne Internet of Things (IoT) platform, NodeMCU microcontroller …

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.