Cables - upkie/upkie GitHub Wiki

Communications from and to servos are transmitted as a differential signal over twisted pairs of wires. These cables have the following specs:

• Connectors: female JST PH-3 (3-pin JST connectors with 2.0 mm (PH) pin-to-pin pitch)
• Wire gauge: 26 AWG (24 AWG to 32 AWG should work)
• Wire length: 42 cm
• Tip: order PVC rather than Silicon wires (they are easier to twist)

Comms cable have female-female connectors, that is, female connectors on both sides. Pins inside are ordered as follows, when looking at the back of the connector (from the cable to the connector):

• Left: CAN_H (typically blue)
• Center: CAN_L (typically green)
• Right: GND (typically black) ⚠️ we leave this one empty

See also the JST PH-3 CAN section in the power-dist board reference.

_{Ask questions about these cables in Hardware discussions.}

The power bus is obtained by daisy-chaining bigger cables through servos and electronics to the battery. These cables don't need to be twisted.

• Connectors: XT-30
• Wire gauge: 14 AWG (16 AWG works too)

We have two types of power cables, as depicted in the pictures to the right:

• Power cables between actuators:
  • Connectors: female-female
  • Wire length: 42 cm
• Power cables to the power dist board:
  • Connectors: female-male
  • Wire length: 20 cm

_{Ask questions about these cables in Hardware discussions.}