Turn your Raspberry Pi into a FM Transmitter
Simply by attaching a 200 mm piece of wire to GPIO pin #4, you can turn your Raspberry Pi into an FM transmitter.
This demo code will only play a mono .wav file, but with a bit of coding it could be used to create a baby monitor, play stereo mp3s, etc.
Details of how to do it, including working code is here:
If you’re starting from scratch, the things you will need from our store are:
A Raspberry Pi Starter Kit: http://www.buyraspberrypi.com.au/shop/product-category/kits/model-b-starter-kits/
Optionally, a GPIO reference card: http://www.buyraspberrypi.com.au/shop/gpio-reference-card/
And 200mm of plain wire.