The real-time departure API for the Wiener Linien, Vienna's public transport company, is available for free. So I thought I could build a monitor just like the ones that you can find all over vienna. I used a Raspberry Pi to connect to the API and an Arduino to control the little LCD display. The two devices communicate over the I2C protocol. Of course it would be possible to control the LCD from the Raspberry Pi directly, but I thought this would also be a good opportunity to learn more about electronics. You can find more information here.