Smart Exhaust Fan Switch
Exhaust fans in washrooms can be connected to the lighting circuit so that these switch on and switch off with the electric light. But...
Multicolour Curtain Backlights
This circuit comprises two parts: a string of 5mm high-intensity white LEDs connected in series and the circuit wired around. IC CD4060 with an...
Clap-Based Digital Volume Control
This clap-based digital volume control offers four levels of volume control. With each clap, the volume of the audio system increases. After the fourth...
Simple Water Temperature Indicator
When bathing a baby, it’s important that the water is neither too cold nor too hot. You test the water by dipping your fingers...
Driveway Alarm
You can install this system in the driveway itself to detect intrusion by a vehicle, person or large animal. It sounds an alarm when...
Versatile DC-DC Converter
Here is a versatile power coupler that connects a device to 5V-19V DC generated from AC mains by a power adaptor. Power adaptors come...
Active Reflector for Pedestrian Safety
Pedestrians crossing roads in badly-lit areas, particularly at night or in the early morning, run a risk of accident. There are readymade arm bands...
Automatic Fan Controller For Air-conditioners
Many central air-conditioning systems (ACs) have the option for cooling and heating both. These have a fan for blowing hot or cold air drawn...
Security Alarm
Thwart any attempt of burglary in your house using this alarm circuit. When someone opens the door of your room, it sounds an alarm...
Dual-Tone Horn
This circuit generates two different frequencies and mixes these to produce a balanced ringing tone, which can be used in burglar alarms or call...
LAPTOP AUDIO AMPLIFIER
Usually, the audio output from a laptop’s built-in speakers is low. A power amplifier is required to get a high volume. Here is a...
DC Motor Control Using PWM
Small DC motors are efficiently controlled using pulse-width modulation (PWM) method. The circuit described here is built around an LM324 low-power quad-operational amplifier. Of...
SAFE CIGARETTE LIGHTER POWER SOCKET
Cigarette lighter sockets available on the dashboards of some vehicles act as a heat source to light cigarettes. Besides, these can power electronic gadgets...
Versatile Battery Charger
This transformer-based versatile battery charger circuit can be used to charge any battery, provided the transformer rating is higher than the battery rating. Normally,...
Electronic Glow-Worm
Here is a circuit that simulates the chirping and glow of a glow-worm bug. The circuit is built around timer IC 7555 (IC1), which...
Air Ioniser
This air ioniser is built around an NE555 timer IC which is configured in astable mode.
The circuit is powered by a 12V battery, which...
Single Control Switch For Fan And AC
Here is an electronic switch that can be used to switch on both the air-conditioner as well as fan of your room, one by...
LED-Based Running Display
Here is a circuit that creates an eye-catching running display effect using LEDs. It can be used to light up borders of animations, pictures,...