Multitone Siren
This multitone siren is useful for burglar alarms, reverse horns, etc. It produces five different audio tones and is much more ear-catching than a...
Overheating Indicator for Water Pipe
This circuit monitors the temperature of the water pipe. If the temperature of the pipe goes above certain limit, it flashes an LED.
Smart Laptop Docking Station
You can easily convert your ordinary docking station into a smart electronic laptop docking station with an anti-theft alarm. The circuit presented here can...
Multi-utility flashlight
This multi-utility flashlight consists of three sections: a flasher, a sound-to-light display and a white LED-based flashlight.
Multi-utility flashlight circuit
The flasher circuit is built around...
White LED Light Probe for Inspection
This white LED light probe circuit is useful for inspecting narrow spaces like the inside of the CPUs, monitors, PCB modules and other electronic...
Digital Night Vision Goggle
At night, on highways, the high-intensity light from the headlight of heavy vehicles blinds oncoming light vehicle drivers (bike riders and car drivers) for...
Water Pump Controller
A water pump controller senses the level of water in a tank and drives the water pump. The circuit described here is built around...
Clock Tick-Tock Sound Generator & LED Pendulum
Wooden-case, battery-operated wall clocks with pendulums are available in the market. Some even have chimes. What is missing is the tick-tock sound of old...
Photo Counter
You can use this photo counter gadget to detect whether somebody opened your cupboard or drawer in your absence. The gadget is small and...
Touch Sensitive Alarm
Security has been a major concern for people for long. Any personal belonging kept out of personal reach is prone to attack and sometimes,...
Emergency Photo Lamp
This emergency photo lamp can be powered either by a rechargeable battery (like 3.6V Ni-Cd) or a non-rechargeable battery (3.0V CR2032). The white LED...
How to Play With Light Using LDR
In electronics, there are many ways to play with light the way you dream. If you are looking for an inexpensive solution, regular light-dependent...
Add-on USB Power Circuit For UPS
Most computer UPS have only 230V output and no USB output. Presented here is a USB power circuit that gives 5V USB output using...
Car Stereo Player Circuit
Using a mobile phone while driving is dangerous. It is also against the law. However, you can use your mobile phone as a powerful...
1-30 Minute Timer
Using this 30 minute timer circuit you can switch on an appliance for a desired time. The circuit provides selectable time settings of 1,...
Car Fan Speed Controller
Using this fan speed controller circuit you can control the speed of 12V DC fans used in cars. The circuit is built around timer...
Mini UPS System
This mini ups circuit provides an uninterrupted power supply (UPS) to operate 12V, 9V and 5V DC-powered instruments at up to 1A current. The...
Duophone: Multiple Numbers Through One Telephone
This simple circuit of a duophone allows you to access two telephone lines through one telephone set. Each telephone conversation will remain entirely separate...