Page 43 - Hacking Roomba
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24 Part I — Interfacing
Locating the Roomba ROI Connector
The ROI connector is located on the top edge of the Roomba, at about the four-o’clock
position when looking down at the Roomba. See Figure 2-3. This location is the same for all
models of Roomba.
clean spot
power max
dirt
status detect
ROI port location
FIGURE 2-3: Location of the ROI port
The port is covered by a small plastic hood, which can be popped off easily with a small
flat-blade screwdriver. Don’t worry about breaking anything. The hood can be quickly snapped
back on.
The ROI Protocol
The ROI protocol is rather rudimentary, as protocols go. The protocol is a simple byte-oriented
binary UART-like serial protocol, operating at 57,600 bps, 8 bits, no parity, one stop-bit (often
represented as 57600, 8N1). The interaction method is command-response, and Roomba never
sends data unless commanded. In fact, there is only one command that elicits a response from
Roomba. Since there is no flow-control, data responses, if present, can be ignored. This allows
very simple devices with only serial output to be connected.
