iRobot CREATE - OPEN INTERFACE Manual page 20

Cliff Front Right Signal Packet ID: 30
The strength of the front right cliff sensor's signal is returned as
an unsigned 16-bit value, high byte first.
Range: 0-4095
Cliff Right Signal Packet ID: 31
The strength of the right cliff sensor's signal is returned as an
unsigned 16-bit value, high byte first.
Range: 0-4095
Cargo Bay Digital Inputs
The state of the digital inputs on the 25-pin Cargo Bay Connector
are sent as individual bits (0 = low, 1 = high (5V)). Note that the
Baud Rate Change pin is active low; it is high by default.
Example Schematic
1
Range: 0 - 31
Bit
7 6 5 4
Button n/a n/a n/a Device
Detect
/Baud
Rate
Change
(pin 15)
Device Detect pin can be used to change Baud Rate. When
device detect/baud rate change Bit is low, the Baud Rate
is 19200. Otherwise it it 57600
iRobot Create Open Interface (OI) Specification
Data Bytes: 
unsigned
Data Bytes: 
unsigned
Packet ID: 3 Data Bytes: 1
unsigned
+5V
10K Ohms
2
DIGITAL_INPUT
3 2 1
Digital Digital Digital
Input 3 Input 2 Input 1
(pin 6) (pin 18) (pin 5)
Cargo Bay Analog Signal
The 10-bit value of the analog input on the 25-pin Cargo Bay
Connector is returned, high byte first. 0 = 0 volts; 1023 = 5
volts. The analog input is on pin 4.
Range: 0 - 1023
Example Schematic
ANALOG_INPUT
Charging Sources Available
iRobot Create's connection to the Home Base and Internal
Charger are returned as individual bits, as below.
Range: 0 - 3
1 = charging source present and powered; 0 = charging source
not present or not powered.
Bit
7
Charging n/a
0
Source
Digital
Input 0
(pin 17)
OI Mode
Create's connection to the Home Base and Internal Charger
are returned as individual bits, as below.
Range: 0 - 3
Number
0
1
2
3
Packet ID: 33
+5V
Light Dependent Resistor
(LDR)
10K Ohms
Packet ID: 34
6 5 4 3 2
n/a n/a n/a n/a n/a
Packet ID: 35
Mode
Off
Passive
Safe
Full
Data Bytes: 
unsigned
Data Bytes: 1
unsigned
1 0
Home Internal
Base Charger
Data Bytes: 1
unsigned
0