[Albert] has made a few PC IR transmitters and receivers using the traditional connection of RS232 serial, and that is fine, but as we are all aware, not every computer has serial ports standard. Searching though normal USB <> RS232 dongles didn’t meet his requirements. Deciding on making it himself, he whipped up this FTDI bit-bang IR receiver / transmitter.
While FTDI makes a range of chips most (if not all) support a bit-bang mode where you can manually control the IC’s pins. The FTDI chip handles the timing, and when paired up with libFTDI makes it pretty painless to control. The software is a work in progress, but [Albert] already has a driver that connects to LIRC, which lets you control a wide array of remote devices and a test program for carrier generation.
Schematics, source, and a few pages of good information are available on his site.
4 thoughts on “Bitbang IR Remote”
Nice. I love FTDI for making such a flexible chip cheap and abundant.
There’s an old trick where you can use a UART at the right baud rate (115200 usually works) to demodulate the carrier. You time the characters coming in rather than sampling the incoming demod’d signal. I think lirc uses this for their RS232 dongle driver. The integrated IR module probably provides much better filtering, but there would be style points in trimming the BOM down to a phototransistor and an LED.
Almost all computers do actually have serial port hardware, it’s in the health monitoring chip, the motherboard makers just stopped supplying headers to it.
So there’s a hack possibility for you although with SMD and tiny feet and multilayer PCB’s it gets hard to get at it.
I wish mobo makers would just put at least a dumb header on the board when it’s already in the chips, dammit.
@What not. I would be great if they would do that. Maybe even include the I2C bus and maybe even a parallel port for digital IO. It would make the boards so much more hackable.
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