Although I already have Left 4 Dead, my wife recently purchased a Roomba. Disappointed by the lack of dueling harnesses for sale on the internet, I decided to get one of the Rootooth Bluetooth serial modules, that allows PC control of the newer Roombas.

Although SparkFun says that they’re out of stock, it seems to be more of an ‘order on demand’ type of thing. I purchased a Rootooth on backorder, and had one posted to me within two weeks. For reference I chose the cheapskate AirMail option with no tracking, and the item turned up within about 3 weeks from my original order date. Although SparkFun had marked the box belot its actual cost, Customs had decided to open and hold it for a few days anyway.

The Rootooth itself. Don’t be disheartened if it doesn’t work out of the box. I discovered three things with mine:

1. You need a Bluetooth dongle that works on Widcomm or the Windows Bluetooth Stack (preferred). I initially tried it with a cheap Bluesoleil Bluetooth dongle, and it failed miserably – Vista refused to connect to the virtual serial port on the Rootooth, and XP would consistently drop the connection every few minutes.
   I eventually bought a Belkin Bluetooth dongle for £10, the F8T013UK. Although it has Widcomm drivers, you can get it running under the Windows stack by following some simple instructions.
2. The Rootooth has been upgraded to use a Firefly Bluetooth module. This version is rumoured to set an incorrect baud rate for the 5xx series of Roombas, despite using the SU,115K instruction. To fix, send the following commands to your Rootooth:
   $$$
   U,115K,N
   Your Rootooth should return back to normal mode (not command mode), and you’re ready to go.
3. There are few websites/forum posts giving information relating to the Roomba 5xx series, even fewer bits of code/software which work with them, and even fewer that work with both.
   I discovered that the 5xx series uses a different set of codes, and that one person had coded for the latest Rootooth/Roomba combination.

So, my Roomba now goes backwards and forwards, and I can monitor the sensors. Next stop, Roomba/Twitter and Roomba/Wiimote.