Last time I showed you how to expose a web service on a Raspberry Pi (or, actually, any kind of device) by using a reverse proxy from Pagekite. On your Pi, you just need a simple Python script.

While the Raspberry Pi has very good support for an I2C bus, a lot of very cool chips – including the in system programmer for just about every ATtiny and ATmega microcontroller – use an SPI bus.