Do-it-yourself projects and technology updates

DIY iPod stereo FM transmitter

After posting about the simple FM transmitter, I decided that I wanted to try to make a stereo transmitter for an iPod. Something like the Griffin iTrip. This would not have to be just for an iPod, but could be for basically any stereo signal that you wanted to send to a stereo. After seeing how simple the mono FM transmitter was, I thought it would not be that bad to do stereo, but I was really wrong. A stereo signal has to be modulated together and carried on a carrier frequency. Everything has to be perfect to make it work. It is a very daunting task, and I could not do it. After a quick google search, I kept running accross stereo FM transmitter kits, and a lot of the cheaper ones use the BA1404 integrated circuit stereo transmitter. I reseached this chip on diyaudio.com (This is a great forums to search for all sorts of DIY audio stuff). I found that it is not really that good of a transmitter, and has a lot of distortion, but I figure that for what I would like to do with it, it should be tolerable.

This is the schematic for the chip. This would have to be tested first, and then a PCB would have to be made. It would be nice if it could be made really small. I am just not sure how small it could be made. If you did not mind losing stereo capability, you could always just mix the two channels together, and use the mono transmitter. This chip is no longer made, but it can still be found at various places on the net. I found a supply of them at electronics-diy.com

The pdf file can be downloaded here[ba1404.pdf]

This entry was posted on Wednesday, January 11th, 2006 at 12:16 am and is filed under Audio, Circuits, iPod. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.