The sensor is connected to the NyBoard via a 4 pin cable.
Solder on the optional LED to ultrasound sensor
The optional RGB LED can be soldered to the four pins of the ultrasound sensor (instructions) to indicate its working status, or can be programmed as a decorative light.
Bend the pins of the ultrasonic sensor for later installation.
Solder 4-pin ultrasonic sensor header to NyBoard
The ultrasonic module is connected to the exposed GPIO pins located in the opposite corner of the board from the TTL connector. You can customize the pin definitions in OpenCat.h. By default definitions, solder the ultrasonic module connection header in the holes labeled “D8 D9 D10 GND” as pictured below.
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, 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 neck pieces. Also notice how the servo wire is organized in the head. Assemble the head group as shown in the head animation.
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 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.
I also included 5 x 1”/4 nuts for mounting other circuit boards.
Bend the hinge L of battery holder to 90 degrees, close to the wall. It functions as a switch. Insert the long screw E through the rivet so that you can better handle the rivet. Insert and push the rivet into the hole on the bottom of the battery holder. Pay attention to the holes’ locations.
The spring attached structure of the battery holder is used for shifting the center of mass when fine tuning gaits.
Pay attention to the long pins of infrared receiver and FTDI port. They are designed to be bent to 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.
Assemble the body group as shown in the body animation.
The serrated structure on the tip of 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 wire go through. Think about symmetry of the four legs. Assemble the shank as shown in the shank animation.
In later versions, we will use plastic pieces for thigh2.
The location has been shown in the Head and Neck section. The trimmed narrower servo arm is designed to be inserted into spring F.
Before closing thigh1 and thigh2, put the wire of the shank through the slot in the middle of the thigh. Think about 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 on the tightness:
Scratch the track using a flat screw driver to reduce friction.
Apply a little paper glue in the track and let dry to increase friction.
Assemble the thigh as shown in the thigh animation.
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 are 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.
Assemble the tail as shown in the tail animation.