Raspberry Pi as an FM Transmitter

This morning I was lazily browsing Reddit when I came across a project by the Imperial College Robotics Society in the UK. It’s code and instructions for using the Raspberry Pi as a low-power mono FM transmitter. When I saw how easy it looked to do, I ran over to my Pi, downloaded the code, and got it running within a matter of minutes (see video above). One of the best parts about this project is that you don’t need much hardware besides the Pi itself. Just connect a 20cm piece of wire to GPIO pin 4 to act as the antenna and then you’re all set. Click on over to their wiki if you’re interested in trying it yourself and how it works. [via Reddit]

27 thoughts on “Raspberry Pi as an FM Transmitter

  1. Somehow I kinda doubt that this device has been type accepted for use as a transmitter by the FCC. I would seriously suggest one exercise extreme caution.

    1. Ah nevermind, add a 3g dongle to be able to dial in from anywhere and its the perfect low cost pirate radio transmitter. I know what my next project is!

  2. In the US the FCC allows unlicensed low power FM transmissions under Part 15 of the Code of Federal Regulations. The wifi/bluetooth/FM radio chip that Raspberry Pi uses passed FCC approval. So, as long as you don’t amplify your signal to broadcast more than 200 feet you should be fine.

    1. Wi-Fi Bluetooth FM chip that Raspberry Pi “uses”? Raspberry Pi contains no such chip, and no such chip was added in this project.

  3. Looking at the link that Matt provided, I wonder how difficult it would be to change the carrier to a standard unmodulated carrier wave, and use it as a morse code (aka cw for hams) transmitter. You would still need a separate receiver and you would need an small amplifier, unless you wanted to run really qrpp. This is a project that I’m excited about!

  4. I have a need to use a (PI) to do VOIP to my two way radio. Has anyone done this using PBX or? and if so please tell me how. Also do we know what usb audio card works well with the PI? Thanks..

  5. It would be interesting to modify the code a bit to allow a GPS (for timing) for transmitter phase locking. A creative and legal way to increase the range of a Part 15 device.

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Matt Richardson is a San Francisco-based creative technologist and Contributing Editor at MAKE. He’s the co-author of Getting Started with Raspberry Pi and the author of Getting Started with BeagleBone.

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