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424 Appendix C — iRobot Roomba Open Interface (ROI) Specification

iRobot® Roomba® Open Interface (ROI) Specification
Remote Control Command Charging State
Packet subset: 2 Packet subset: 3
Range: 0 – 255 (with some values unused) Range: 0 – 5
Data type: 1 byte, unsigned Data type: 1 byte, unsigned
The command number of the remote control command currently A code indicating the current charging state of Roomba.
being received by Roomba. A value of 255 indicates that no
remote control command is being received. See Roomba remote Code Charging State
control documentation for a description of the command values.
0 Not Charging
1 Charging Recovery
Buttons 2 Charging
Packet subset: 2 3 Trickle Charging
4 Waiting
Range: 0 – 15
5 Charging Error
Data type: 1 byte, unsigned
The state of the four Roomba buttons are sent as individual bits Voltage
(0 = button not pressed, 1 = button pressed). Packet subset: 3
Bit 7 6 5 4 3 2 1 0 Range: 0 – 65535
Button n/a n/a n/a n/a Power Spot Clean Max
Data type: 2 bytes, unsigned
Distance The voltage of Roomba’s battery in millivolts (mV).
Packet subset: 2
Current
Range: -32768 – 32767
Packet subset: 3
Data type: 2 bytes, signed
Range: -32768 – 32767
The distance that Roomba has traveled in millimeters since the
distance it was last requested. This is the same as the sum of Data type: 2 bytes, signed
the distance traveled by both wheels divided by two. Positive The current in milliamps (mA) flowing into or out of Roomba’s
values indicate travel in the forward direction; negative in the battery. Negative currents indicate current is flowing out of the
reverse direction. If the value is not polled frequently enough, it battery, as during normal running. Positive currents indicate
will be capped at its minimum or maximum. current is flowing into the battery, as during charging.
Angle Temperature
Packet subset: 2 Packet subset: 3
Range: -32768 – 32767 Range: -128 – 127
Data type: 2 bytes, signed Data type: 1 byte, signed
The angle that Roomba has turned through since the angle was The temperature of Roomba’s battery in degrees Celsius.
last requested. The angle is expressed as the difference in
the distance traveled by Roomba’s two wheels in millimeters, Charge
specifically the right wheel distance minus the left wheel
distance, divided by two. This makes counter-clockwise angles Packet subset: 3
positive and clockwise angles negative. This can be used to Range: 0 – 65535
directly calculate the angle that Roomba has turned through
since the last request. Since the distance between Roomba’s Data type: 2 bytes, unsigned
wheels is 258mm, the equations for calculating the angles in The current charge of Roomba’s battery in milliamp-hours (mAh).
familiar units are: The charge value decreases as the battery is depleted during
Angle in radians = (2 * difference) / 258 running and increases when the battery is charged.
Angle in degrees = (360 * difference) / (258 * Pi).
Capacity
If the value is not polled frequently enough, it will be capped at Packet subset: 3
its minimum or maximum.
Range: 0 – 65535
Note: Reported angle and distance may not be accurate. Roomba
measures these by detecting its wheel revolutions. If for example, the Data type: 2 bytes, unsigned
wheels slip on the floor, the reported angle of distance will be greater than The estimated charge capacity of Roomba’s battery. When the
the actual angle or distance.
Charge value reaches the Capacity value, the battery is fully
charged.
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