Sensor and control circuit diagrams

VCS using 555 Timer

In this circuit the 555 timer is used in a novel way, as a voltage controlled switch.

Fan Controller

This circuit controls very accurately a fan of any size. Just adjust the associated resistors for a different type like the R6 resistor of 100 ohm, 2 watt type and you're all set. The above circuit diagram is for a small 12 volt fan, the size and type determined by the user.

Clap Relay

Clap sensitive on-off Relay. 3V Battery operated, small portable unit

Whistle Responder

Beeps when hears your whistle. A gadget suitable for key-holders, games etc.

Water Activated Relay

In his circuit Marin has used two transistors wired as a high gain compound pair.

Water Pump Relay Control

Water reservoir automatic level control. Simple circuitry - 12V supply

Sound Operated Switch

A sound operated switch with a relay driver.

AC Current Monitor

Senses high current-flow into power cables No wire-cutting, three versions available

Parking Light Switch

This is a simple parking light switch. The idea is that you drive your car towards your garage. You shine your headlights at the sensor, which switches on an external light . If you don't have a garage the sensor can be placed on a wall or post, and the external light will illuminate the area while you park and leave your vehicle. The circuit also has manual on and off controls.

Frost Alarm

A simple thermistor triggered switch with adjustable threshold. It triggers with cold temperatures so may be used as a frost alarm or cold temperature switch.