iRobot Roomba Open Interface (OI) pinout

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The Roomba Open Interface (OI) is a software interface for controlling and manipulating Roomba?s behavior. The software interface lets you manipulate Roomba?s behavior and read its sensors through a series of commands, including mode commands, actuator commands, song commands, and sensor commands that you send to the Roomba?s serial port by way of a PC or microcontroller that is connected to the Mini-DIN connector.

 

Pin Number	Pin Name	Description
1,2	Vpwr	Roomba battery + (unregulated)
3	RXD	0 – 5V (TTL) Serial input to Roomba
4	TXD	0 – 5V (TTL) Serial output from Roomba
5	DD	Device Detect input (active low) – used to wake up Roomba from sleep
6,7	GND	Battery ground

RS232 to TTL converter is necessary to connect this device to PC.

 

Baud: 115200 or 19200
Data bits: 8
Parity: None
Stop bits: 1
Flow control: None

When powering on Roomba, hold down the Clean/Power button. After about 10 seconds, Roomba plays a
tune of descending pitches. Roomba will communicate at 19200 baud until the power is turned off. Or use the Baud Rate Change pin (pin 5 on the Mini-DIN connector) to change Roomba’s baud rate. After
turning on Roomba, wait 2 seconds and then pulse the Baud Rate Change low three times. Each pulse
should last between 50 and 500 milliseconds. Roomba will communicate at 19200 baud until the
processor loses battery power.

The Roomba OI has four operating modes: Off, Passive, Safe, and Full. After a battery change or when
power is first turned on, the OI is in “off” mode. When it is off, the OI listens at the default baud rate
(115200 or 19200 - see Serial Port Settings above) for an OI Start command. Once it receives the Start
command, you can enter into any one of the four operating modes by sending a mode command to the
OI. You can also switch between operating modes at any time by sending a command to the OI for the
operating mode that you want to use.