4 🏗 Assemble the Frame
"The whole is more than the sum of its parts." 🔩
You may take a glance at the overall assembling process before starting. Some updated components are noted in the following paragraphs.
Most of the servo arms on the model are trimmed from the cross-shaped arm I. Since there will be more unused straight arms, you can practice trimming with them first.
An alternative method to trimming is using a half-burned knife to cut the plastic parts off. Leave a little bit longer because melted plastic will have a rounded edge.
As we switch servo suppliers, the servo arms also changed a little bit (as shown below). To reduce confusion, the servo arm I can be used for most of the joints, just trim it accordingly. Servo arm K is used for the tail. Servo J can be omitted.
Note that the base should only be partially assembled for later calibration. Otherwise, it will be difficult to insert the servo between neckpieces. Also, notice how the servo wire is organized in the head. Assemble the head group as shown in the head animation.
- NyBoard only
Note that without the Raspberry Pi, the NyBoard is mounted to the underside of y1 with the servo connections facing downward. In later versions, the y1 piece is designed to be symmetric so that both ends have two screw holes.
- NyBoard with Raspberry Pi
Use y1Pi to replace y1, and add Pi Stand. Pay attention to the location of the pink pieces. Note that with the Raspberry Pi, the NyBoard is mounted on top of y1Pi.
- Other controllers
I also included 5 x 1”/4 nuts for mounting other circuit boards.
Pay attention to the long pins of the infrared receiver and FTDI port. They are designed to be bent in favorable directions. Don’t bend the pins too often or it will lead to metal fatigue. Observe the adjusted configuration if you want to mount a Pi.
The serrated structure on the tip of the shank is already good for walking. The rubber toe is optional to increase friction and soften each step.
Pay attention to the direction that the wire is twisted. The small dent on the long edge is designed to let the wire go through. Think about the symmetry of the four legs. Assemble the shank as shown in the shank animation.
In later versions, we will use plastic pieces for thigh2.
Before closing thigh1 and thigh2, put the wire of the shank through the slot in the middle of the thigh. Think about the symmetry of the four legs.
The servo arm should be able to slide in the track on thigh2 with subtle friction after thigh1 and thigh2 are screwed together. You can tune the tightness of screw C to achieve proper friction. If you need more control over the tightness:
- Scratch the track using a flat screwdriver to reduce friction.
- Apply a little paper glue to the track and let dry to increase friction.
The screw D is installed in the third hole counted from the center of the servo arm K. Pay attention to the order that every piece is stacked. The wheel (tail2) should be able to rotate with little friction, and the whole tail should be able to tilt by a small degree.