5 🔌 Connect Wires

"Everything is connected." 🤝

5.1. Joint map

Nybble's servos are connected to NyBoard's PWM pins symmetrically and resembles the nerves along the spinal cord. Though Nybble doesn't have shoulder roll DoF, those indexes(4~7) are reserved for the full OpenCat framework.

NyBoard V0_1 and V0_2 have different PWM pin orders, but the physical servo connection remains the same. All adjustments are done in the software.

Use h for head, t for tail, r for shoulder roll joint, s for shoulder pitch joint, k for knee joint, F for front, H for hind, L for left, R for right, the full joints map of OpenCat is:

5.2. Plug in the servos

Observe the indexing pattern to connect servos with correct PWM pins. Be careful with the wires’ direction. The brown wire of servo is GND, while the GND on NyBoard V0_1 are along the centerline. On NyBoard V0_2 they are opposite.

(NyBoard V0_1 Front) (NyBoard V0_1 Back)

A quick check is that all On NyBoard V0_1 the brown wires should be far away from the board surface. On NyBoard V0_2 the brown wires should be close to the board surface.

NyBoard V0_1

For NyBoard V0_2, the location of servo wires will still be the same, but their direction of colors will be opposite

NyBoard V0_2

5.3. Wiring

After calibration, troubleshooting and final assembling, It’s time to think about wiring routes to make Nybble look neat. There are multiple slots on the frame designed as wire organizer. Feel free to develop your own style for connecting future accessories. Make sure the wires doesn’t get in the way of servos‘ movement.

Below is my wiring routes.

NyBoard alone

NyBoard with Raspberry Pi

5.4. Connect Ultrasonic Sensor

If you have not already, plug in the 4 pin cable, make a note of which cable colors are attached to which signals. When looking into Nybble’s eyes, the connections from left to right are:

VCC	Trigger	Echo	Ground

Connect the other end of the cable to the header you soldered in place earlier in assembly. Use the following mapping

Sensor Side	NyBoard Side
Vcc	D8
Trigger	D9
Echo	D10
GND	GND