Contactless Battery Charger
These days mobile phones with contactless charging are readily available. The circuit shown here explains how contactless charging of a battery can be done,...
Vibration Sensor
Presented here is a sensitive alarm using a vibration sensor for application as a simple surveillance system for protecting doors and windows. It can...
Water Level Indicator with Alarm
Here is a simple, versatile circuit which indicates the level of water in a tank. This water level indicator alarm consists of twelve levels....
Dual-Laser Security System Using An Old Feature Phone
A security system having a single laser beam may not be very effective as any moving object or animal can interrupt it, causing a...
Water Level Indicator
Here’s a simple water level indicator for overhead tanks that uses three LEDs (LED1, LED2, and LED3) to indicate minimum, middle, and maximum water...
Sound Operated Timer
This sound operated timer is based on LM324 quad-operational amplifier and NE555 timer. Time delay can be set from a few seconds to 30...
555 Timer PWM Audio Amplifier
The “555” integrated circuit is a general-purpose timer useful for a variety of functions. In this 555 audio PWM project, we explore its use...
IR Remote Control for Home Appliances
Most remote controls around us, use IR for signal transmission. An IR remote control for home appliances helps you connect to your decices at...
Mobile Charging With Heat Using A TEG Module
This circuit can come in handy when you are camping in a remote area where there is no electricity available to charge your mobile...
Hybrid Solar Charger
Efficiency of a solar charging system depends on the weather conditions. Usually the solar panel gets four to five hours of bright sunlight in...
Remote Control for Toy Car
Make any battery-operated toy car remote controlled using this circuit. This remote controlled toy car circuit, consisting of an infrared transmitter-receiver pair, uses IR...
Noise Level Alarm
Noise is a serious environmental problem that affects us in our daily life. There is scientific evidence supporting that noise exposure can cause hearing...
Voice Recorder and Playback System
There are several types of voice recorder and playback systems available in the market but most of them are expensive and their circuits are...
Low Power Voltage Doubler
All miniature electronic devices operate off batteries. Some of them need higher than the standard battery voltages to operate efficiently. If the battery of...
LED As Light Sensor
Usually light dependent resistors (LDR) and photodiodes are used as light sensors to activate or deactivate circuits based on the presence or absence of...
Cistern Overflow Alert System
The overflow alert system presented here will electronically monitor cistern (tank that holds water to flush the toilet) overflows that can otherwise cause seepage...
School/College Quiz Buzzer
Manual buzzers used for quiz competitions in schools and colleges create a lot of confusion in identifying the first respondent. Although there are circuits...
IoT Based Smart Camera Using Android And Raspberry Pi
Presented here is a project that lets your Raspberry Pi (RPi) turn into an IoT based smart camera and then control and watch live...