If you’re building a robot, you’re making lots of electrical connections, so you’re dealing with lots of pins. The following table shows the signal for expansion connectors and pin numbers. It can help prevent unwanted cross connections.

Expansion Connector Pin Number Signal Expansion Connector Pin Number Signal
1,2 Ground 16 P11 Green LED
3,4 +5 volts 17 P12 Jumper J7
5 P0 Left whisker 18 P13 Jumper J6
6 P1 Right whisker 19 P14 Switch 1
7 P2 Rear whisker 20 P15 Switch 2
8 P3 Temp sensor 21 RB7 from coprocessor
9 P4 Light sensor 22 Encoder pulse
10 P5 PIR sensor 23 Servo motor #1
11 P6 RC drive motor input 24 Servo motor #2
12 P7 Speech output 25 Servo motor #3
13 P8 Network to coprocessors 26 Servo motor #4
14 P9 Speaker 27–40 Unused
15 P10 Red LED