Assembly

These are the main stages of putting the prototype together, in order. Detailed instructions and photos for each step are still being written as the first prototype is finished.

1. Print and clean up the parts#

   Print the palm and finger bones in PLA or PETG (see the Build guide). Remove supports, and make sure the joint holes and tendon channels are clear so the tendons can slide freely.

2. Assemble the finger joints#

   Join the bones with their hinge pins, one joint at a time. Each joint should swing freely through its full range with no rubbing. Friction here is felt by the motor on every move.

3. Mount the motors#

   Fix the eight 28BYJ-48 motors in their mounts, with a 1 cm radius spool on each output shaft. Label every motor M1 to M8 now; the numbers are used everywhere (see the pin map in Electronics).

4. Thread the tendons#

   For each joint, run a tendon loop from the motor's spool, along the finger, around the joint and back. One side of the loop closes the joint, the other side opens it. Tension them just enough to remove slack, with every joint straight.

5. Wire the electronics#

   Connect each motor to its ULN2003 board, and each board to the ESP32-S3 pins in the pin map. Connect the separate 5 V / 2 A supply to the driver boards, and join its ground to the ESP32's ground. Leave the motor power off for now.

6. First power-on, one motor at a time#

   Flash the firmware with only USB connected, then follow the first power-on checklist in Electronics. Straighten every joint by hand before switching on the motor power.