Selfmade RF remote control
As hobby project while school, a friend and I built an RF remote control for my slide projector. My
friend built the hardware, and I wrote the Assembler programs for the sender and
the receiver.
The hardware were two small devices; a sender which is powered by a 9V battery which
just sends a predefined bit pattern over an RF module. The receiver is plugged into
the slide projector and gets its power from the projector. It listens for signals
from the RF Receiver module and checks if the pattern matches. If so, it signals
the slide projector that the button is pressed. As long as the button on the sender
is hold down, the slide projector receives that signal. So it's possible to go back
one slide by holding down the button for more than about 500ms.
If you are interested in building the same for your slide projector, I can send you
the schematics of the hardware. The assembler programs are available for download here:
sender.asm
receiver.asm
The programs are for the microprocessor ATTiny12 by Atmel.
You can compile the assembler programs with tavrasm and
send the bytecode to the chips with SP12.