5 🔌 Connect Wires
"Everything is connected." 🤝
Nybble's servos are connected to NyBoard's PWM pins symmetrically and resemble 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.
Use h for the head, t for the tail, r for shoulder roll joint, s for shoulder pitch joint, k for knee joint, F for the front, H for hind, L for left, R for right, the full joints map of OpenCat is:
Observe the indexing pattern to connect servos with correct PWM pins. Be careful with the wires’ direction. The brown wire of the servo is GND, while the GND on NyBoard V0_1 is along the centerline. In later versions of NyBoards, they are opposite.
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.
Even though the PCB layouts vary on different NyBoards, the wiring pattern is the same. You don't need to read the indexes of the servo pins when plugging the servos. The joint mapping is done automatically in the OpenCat code. You just need to select the right board version when uploading the code.
Install the head, tail and leg components as following picture:
You can install the legs with the reference of a triangle ruler or the L-shaped ruler included in the kit.
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 a wire organizer. Feel free to develop your own style for connecting future accessories. Make sure the wires don’t get in the way of the servos‘ movement.
Below are my wiring routes.
NyBoard with Raspberry Pi