Mutchus

This is a simple and low-cost automatic turn-off electronic circuit diagram; this circuit provides an automatic turn-off feature after a time that can be set from 1 minute to 10 minutes by the 470k pot. Circuit Diagram:

Use this circuit instead of a standard on-off switch. Switching is very gentle. Connect unused input pins to an appropriate logic level. Unused output pins *MUST* be left open!. First 'push' switches ON, another 'push' switches OFF. You can use 1/4 watt resistors if they are metal-film type. Any proper substitute will work for Q1, including the european TUN's. For C2, if you find the relay acts not fast enough, leave it out or change to a ceramic cap between 10 and 100nF. Parts List All resistors are 1/2 Watt and 5% tolerance. R1 = 10K R2 = 100K R3 = 10K C1 = 0.1µF, Ceramic C2 = 1µF/16V, Electrolytic D1= 1N4001 Q1 = 2N4401 (ECG123AP, NTE123AP, etc.) IC1 = 4069, CMOS, Hex Inverter (14069), or equivalent S1 = Momentary on-switch Copyright © Tony van Roon

This Laser Controlled ON/OFF switch circuit is built around a 555 timer using very few components. Since the circuit is very simple, even a novice can easily build it and use it as a controlling device. A laser pointer, now easily available in the market, can be used to operate this device. This circuit has been tested in operational conditions from a distance of 500 meters and was found to work satisfactorily,though it can be controlled from still longer distances. . Laser Controlled ON/OFF switch Circuit diagram : Laser Controlled ON/OFF Switch Circuit Diagram Aiming (aligning) the laser beam exactly on to the LDR is a practical problem. The circuit is very useful in switching on/off a fan at night without getting off the bed. It can also be used for controlling a variety of other devices like radio or music system. The limitation is that the circuit is operational only in dark or dull lit environments. By focusing the laser beam on LDR1 the connected gadget can be activated throug...