Pressure Sensitive Alarm
Here is a low-cost, pressure sensitive alarm. The alarm uses a home-made pressure sensor, which works as a variable capacitor using two copper-clad boards...
PC Multimedia Speaker
This is a circuit for USB compatible low cost and low power multimedia speakers for PC.
Solar Lighting System
The world cannot continue to rely for long on fossil fuels for its energy requirements. Fossil fuel reserves are limited. In addition, when burnt,...
Fire Alarm
With the onset of summer, chances of fire accidents increase. Such fire accidents can be prevented if timely alarms are available. The fire alarm...
Remote Control Tester
Here is a simple remote control tester for checking the basic operations of an infrared remote control unit. It is low cost and easy...
Multidoor Opening Alarm with Indicator
This door opening alarm alerts you of intruders. You can use it for up to three doors. You simply need to fit a small...
Musical Touch Bell
Here is a musical call bell that can be operated by just bridging the gap between the touch plates with one’s fingertips. Thus there...
Smart Cellphone Holder
This smart cellphone holder makes sure that you don’t forget to carry your mobile phone. Fitted in the car, it keeps searching for the...
Sensitive Vibration Detector
This sensitive vibration detector is realised using readily available, low cost components. One of its many applications is in a rolling shutter guard for...
Digital Counter
A counter whose logical output increments in steps on receiving clock pulses is used for a variety of counting and timing applications. It is at the heart of digital clock circuitry and other similar timing devices.
Drinking Water Supply Alarm
The State Jal Boards supply water for limited duration in a day. Time of water supply is decided by the management and the public...
Mock Alarm with Call Bell
Here is a fully automatic mock alarm to ward off any intruder to your house. The alarm becomes active at sunset and remains ‘on’...
Heat Sensitive Switch
At the heart of this heat sensitive switch is IC LM35 (IC1), which is a linear temperature sensor and linear temperature-to-voltage converter circuit.
The converter...
Optical Remote Switch
Using this optical remote control, you can switch on/off any electrical or electronic load. Like any remote control system, it has a mini transmitter unit and a receiver unit to activate the relay.
Infrared (IR) Illuminator
Infrared (IR) illuminators are widely used to improve the image-capturing quality of security cameras fitted in dark zones. Just like our eyes, cameras also...
Low-cost Intercom Circuit Using Transistors
This is a circuit for a low cost intercom that is made by using transistors.
Sound Operated Lamp Switch
This inexpensive, fully transistorised sound operated lamp switch is very sensitive to sound signals and turns on a lamp when you clap within 1.5...
Infrared Toggle Switch
This infrared toggle switch can be controlled by any TV/VCR remote operating at 38kHz frequency. The circuit uses readily available, low-cost components and can be assembled on a small veroboard.