The REV Robotics Expansion Hub (REV-31-1153) is a low-cost educational device that can communicate with any computer (commonly the REV Robotics Control Hub or an Android Phone) to provide the interfaces required for building robots and other mechatronics. The Expansion Hub was purpose built to stand up to the rigors of the classroom and competition field. It features a mature firmware designed for basic and advanced use cases with the ability to be field upgraded in the future.
The IO ports of the Expansion Hub are identical in specification to the Control Hub. Within this documentation, many sections may refer to the Control Hub, but the connections are the same for the Expansion Hub.
The REV Robotics Expansion Hub is an approved device for use in the FIRST Tech Challenge and FIRST Global.
Port Label
Qty
Connector
Description
Battery
2
XT30
Connect one 12V NiMh battery, add an Expansion Hub with second port
Motor
4
JST VH, 2-pin
Motor power output
Encoder
4
JST PH, 4-pin
Quadrature encoder input
Servo
6
0.1” Header
Extended range 5V servo output (500-2500ms)
5V Aux Power
2
0.1” Header
Auxiliary device 5V/2A
Analog
4
JST PH, 4-pin
Analog input 0-5.0V measurement range with two channels per connector. 3.3V provided on the connector power pin.
Digital
8
JST PH, 4-pin
Digital Input/Output with two channels per connector
I2C
4
JST PH, 4-pin
Four separate I2C busses, 100kHz/400kHz bus speed
RS485
2
JST PH, 3-pin
Serial communication port to add a Hub (Control or Expansion)
UART
2
JST PH, 3-pin
Debugging only
MINI USB
1
USB Mini-B
Connect directly to the Robot Controller Android device or PC
Specifications
The following tables provide the operating and mechanical specifications for the Expansion Hub.
DO NOT exceed the absolute maximum electrical specifications. Doing so will cause permanent damage to the Expansion Hub and will void the warranty.
Input Power Specifications
Parameter
Min
Typ
Max
Units
Operating voltage range (
VIN
)
8
12
15
V
Absolute maximum supply voltage
-
-
15
V
Motor Port Specifications
Parameter
Min
Typ
Max
Units
Continuous output current †
-
-
10
A
Absolute maximum output current ‡
-
-
20
A
†
Exceeding the continuous current maximum depends on many thermal factors. The outputs will self protect once they approach their thermal limit.
‡
Maximum current is ultimately limited by the in-line battery fuse.
See Sensors - Digital for more information on using the digital ports. See Using 5V Sensors for information on using 5V logic level devices with the digital ports.
Analog Port Specifications
Parameter
Min
Typ
Max
Units
Analog port input voltage range †
0
-
5
V
Analog port supply voltage
-
-
3.3
V
Analog port total supply current
-
-
500
mA
†
The analog input will accept up to 5V. When using 5V analog sensors, a custom wiring harness is needed to provide 5V of power for the sensor as the power pin provides 3.3V.
See Sensors - Analog for more information on using the analog ports.
I2C Port Specifications
Parameter
Min
Typ
Max
Units
I2C port input voltage range
0
-
3.3
V
I2C port supply voltage
-
-
3.3
V
I2C port total supply current
-
-
500
mA
Bus speed
-
100/400
-
kHz
See Sensors - I2C for more information on using the I2C ports. See Using 5V Sensors for information on using 5V logic level devices with the I2C ports.
Servo Port Specifications
Parameter
Min
Typ
Max
Units
Servo output signal voltage
0
-
5
V
Servo port supply voltage
-
5
-
V
Servo port pair total supply current †
-
-
2
A
Absolute maximum total supply current ‡
-
-
5
A
Servo port output pulse range
500
-
2500
μs
†
Total supply is shared across pairs of ports (0-1, 2-3, 4-5)
‡
The 5A total supply current for all servo ports and +5V power ports is shared.
+5V Power Port Specifications
Parameter
Min
Typ
Max
Units
+5V power port output voltage
-
5
-
V
+5V power port pair total supply current †
-
-
2
A
Absolute maximum total supply current ‡
-
-
5
A
†
Total supply current is shared across both ports
‡
The 5A total supply current for all servo ports and +5V power ports is shared.