In this exercise we see how to use an IR (infrared) remote control as the input keyboard. Any television remote control may be used, so long as it obeys the Sony code format, which is actually very common. Here are the devices I've tested it with:
On the left is a Westinghouse remote which I bought surplus for $2 from All Electronics several years ago. In the middle is one of those programmable universal units; I got it from Amazon and set it to send Sony codes. Finally, on the right is a weird little thing, which I also secured from Amazon. It's intended for gags like changing the television channel in airports or at sports bars (right when something crucial is happening on the screen!). But it also works quite well with this circuit. Speaking of which, here's the schematic:
At the heart of it is an IR receiver operating on a 38 kHz carrier frequency. These are a dime a dozen anymore. I've picked up two different styles, made by two different manufacturers, surplus from All Electronics in the past, and both perform flawlessly.
As part of this project, I've written a complete library unit for the IR receiver. Be sure to read it over, for it explains the many possibilities at your disposal.
Click to get the source code.
Click to get the schematic PDF.
Next Project: PS/2 Keyboard
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