2B-SHORT DURATION REMOTE CONTROL TIMER PROJECTED SPECIALTIES
This project can be used as a remote switch. You can utilize this switch for toys,show room lights, garae, TV, Tape-recorder, radio, stereo; video system and other appliences to put them ON/OFF.
TECHNICAL DESCRIPTION AND WORKING
The project has developed and successfully tested O.K. at the TV Engineer Technical lab.
The project is based on IC 555. The IC is a commonly available popular IC and used as digital as well as analog. Here, it has been used as an Astable Multivibrater. The project is designed to operate with-in a range of 1.5 meters to 2 meters. But the range can be increased by using a photo diode and increasing the number of infra red LED. The remote section of the project can be assembled very easily which works on 3v DC. When 3V DC is applied to the Infra red LED, it produces Infra red Rays. The Infra red Rays fall on the photo diode and by this pin No2 of IC 555 used in the section receiver section on recevices section pulse and puts the IC ON. The desired time of the projent is valued at pin No 6 the IC. You can use condensors of higher values to increase the time interval. The output available at pin No 3 of the IC is fed to the base of tansistor BC 148 for amplification. The relay is connected in series wit
the transistor. When the base of the transistor receives pulse, the relay comes to ON position. The transistor BC 148 also works as a better as it balances the IC with the load. We can set the time internal more accurately by the preset connected to pin No 6 of IC.
Note – If the readers may not have Infra red LED and photo diode look a like do not blue light when they slow. The photo diode shows low resistance on high intensity light and high resistance on LOW intensity light while testing on multimeter. This a very common method of checking.
PRECAUTIONS WHILE ASSEMBLING
1.Do not allow the current to flow on Infra red LED for a long time. It may set damaged.
2.Use rotary switch if good quality as it is used in time circuit.
3.To increase time interval,use 10m preset in place of 5M and 4700 MFD condenser in place of 1000 MFD.
4.Use IC base mounting IC. Other wise the heat of soldering iron may damage the IC.
LIST OF COMPONENTS
Type from T.O.U.E.D Vol II page=II.