Computer controlled Universal Remote Control

[tarang]

universal remote control through computers

Hello Mate,

I am doing my final year project, in which i need to construct a Universal Remote Control fro TV.
The controller will be controlled by the computer. The computer will send the appropriate signal through Serial / Parallel port to the IR transmitter device and the IR of the transmitter will send the signal to the TV.

I want to know how can i construct such device. I guess it should be very simple, like one IR diode, some resistor and the wire to connect to the PC port. But i need some advice on it....
My main question is how can i send such signals?...how to start the coding? Can i simply write a C++ program that activates the serial port and send the signals? or is there any simpler way?

Can any one guide me in correct direction?

Thanx in Adv.....

 

[VVV]

computer controlled universal remote control

IR remote controls use a carrier, that is a relatively high frequency signal, that gets modulated. The carrier frequency is usually about 38kHz. The modulation is always 0 or 100%, tha is you either send the carrier or nothing.

There are several types of encoding, the most popular of them being RC-5, developped by Philips. A bit is transmitted as a sequence of either 0-1 or 1-0, that is half the time the carrier is transmitted, half the time it is off. The on an off times are, if I remember correctly, 0.889ms.

For more info, look here https://www.sbprojects.com/knowledge/ir/rc5.htm or do a search on RC-5.

So to answer your question, it's not as simple as sending characters out the serial port. You will need to somehow set the baud rate to something close to 38kHz, then send a few "characters", such as 0xAA or 0x55, for each active portion of the signal.
Perhaps you will have better luck with the parallel port, since you can toggle the lines any way you want, without having to go through the UART, which may not even accept your special baud rate.

 

[banjo]

I think the parallel port is too slow. There are some tricks to using the serial port. Take a look at:

https://www.lirc.org/transmitters.html

From Linux, they can operate some IR devices with just an IR diode, a blocking diode and a resistor.

Of course, the range is limited and it cannot do ALL TVs, stereos, etc.