Albert's FTDI IR Receiver/Transmitter
We found Albert Huitsing's page on how to make a homebrew IR receiver and transmitter using an FTDI MM232R prototype module and thought we had to give it a try ourselves. We were thinking this little module would be the perfect thing to interface our motorola style IR receivers and Tivo Style IR Transmitters to the USB port. To do this, all we would need to do is modify Albert's design to include the necessary 1/8" (3.5mm) jacks.
We decided to run this test by making a small board. This way, we figured we could make up a couple for only a bit more money and share the results with others. The board is pictures above with our 1/8" plug IR receiver cables plugged into it and it works great (notice the improved styling on the IR Receiver head as well).
Albert also has a patch on his website to allow for transmitting, but we haven't tried that yet. We did put an option to install another 1/8" jack on the back side for connection to our tivo style ir blaster. We'll post here when we get around to testing transmitters.
We did notice a couple items when testing the receiver so far that should be noted:
(1) In the lirc daemons/hw_ftdi.c we had to change the sample rate from 16 to 32. It seems our FTDI chips sample at double the rate as the ones Albert tested. We didn't see a spec in the datasheet showing the correct sample rate. We also had to compensate for the doubling of sample rate by halving the baud rate from 4800 to 2400.
(2) On computers with only a USB 1.1 port, mode2 worked, but irw did not. On all computers we tested with USB 2.0 ports both mode2 and irw worked as expected.
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