The Roomba has a 'device detect' pin that you must pulse low to turn on the Roomba and initialize the connection. Sometimes people connect this to the RTS (or was it the CTS?) pin of the serial adapter. Device detect might be the same as pushing the Roomba's power button. After the Roomba prints the model and firmware version over the serial port it should be ready to receive commands.

I wouldn't recommend connecting the 5V device detect pin directly to the 3V Pi. You could just short it to ground manually (and briefly) to get started.

Serial connection between Raspberry Pi and Roomba
Is there any way to add "Send &amp; Delete" button in GMail like "Send &amp; Archive" which can be enabled in labs. any add-ons, extensions or greasemonkey script will do.
