The Raspberry Pi is a small computer developed by the Raspberry Pi Foundation.
This piece of hardware is perfect for streaming data to the Tangle for e.g.
All you need are a few lines of code and sensors connected to the Raspberry.
The Raspberry Pi runs on low power which is great for a huge variety of usecases.
The possibilites with the Raspberry Pi and IOTA are endless since you can program it to fit for your need.