The RooStick by RoombaDevTools.com is pretty cool. It’s tiny and it’s USB, which is about all you need for me to bring you home.
But if you want to hack together something similar and you don’t want to build a huge honking Roomba serial tether, you could build the Roombongle!
The Roombongle is a USB adapter that allows you to control your Roomba from your computer, via the Roomba’s SCI protocol. Don’t have a Roomba? Get one!
