Simple 555 Timer Based Animal Repeller Circuit is small device to keep animals away, it make high sound which animals do not like and humans mostly do not hear it; also its main part is IC 555 timer which make high frequency sound. Sound is around 15 kHz to 120 kHz (ultrasonic), therefore, this circuit […]
Timer Based Mosquito Repeller Power Saver Circuit
Mosquito repellers are popular to keep bugs away, as they use ultrasonic sound or chemical spray; but if it is always ON then they use much electricity. To solve this problem, we designed a timer-based mosquito repeller power saver circuit, it switches the repeller ON and OFF at fixed intervals to reduce power consumption and […]
Simple LED Alert for Telephone Off-Hook Detection Circuit
This simple LED circuit detects voltage drops when we lift the handset, actively turning ON an LED to show that our telephone is in use. Also, circuit is good for old phones with no light alert and it is very useful for shared phones and stops call interruptions. Here, circuit runs on simple 3V battery […]
Mobile Incoming Call Detector Circuit
Mobile Incoming Call Detector Circuit is a smart project, which detect incoming call and make LED light up. Circuit is good for noisy places where ringtone is hard to hear and can catch RF signal from phone when call comes. In addition, the circuit uses LC circuit, transistor, 555 timer to turn ON LED and […]
Electromagnetic Telephone Ringer Circuit
Electromagnetic Telephone Ringer Circuit helps us know when call comes and when there is no need connect to phone line. Also, this circuit is useful when there is no access or do not want to touch phone line, as it works by sensing electromagnetic field from ringing signal and then buzzer turns ON; furthermore, the […]
12V Battery Powered Fluorescent Lamp Driver Circuit
Fluorescent lamp need high voltage AC to start and keep glowing., so we have designed this 12V Battery Powered Fluorescent Lamp Driver Circuit which uses 12V battery to run fluorescent lamp. It change low voltage DC from battery to high voltage AC for the tube and it is good for battery device and emergency light. […]