Build your own machine

Repo
Download from this site

Firmware

Download firmware from repo / from this site

Note

• While holding down the “BOOT” button, connect the USB cable to the PC.
  or
• Connect the USB cable to the PC.
• Keep holding the BOOT button.
• Press and release the RESET button.

A storage device named “RPI-RP2” will be mounted, just like a USB flash drive.
Drag and drop the .uf2 file into the “RPI-RP2” drive.

Python

“Python code

The code is designed for Python >= 3.10
Dependencies:

pyserial >= 3.4
cobs >= 1.1

install python

% python3 -V
Python 3.13.5

% pip install pyserial
Defaulting to user installation because normal site-packages is not writeable
Requirement already satisfied: pyserial in ./Library/Python/3.9/lib/python/site-packages (3.5)
% pyserial --version
zsh: command not found: pyserial

% python3.13 -m pip install --user pyserial
Successfully installed pyserial-3.5

% python3 -m pip install cobs --user
Successfully installed cobs-1.2.1

code

Serial port

% ls /dev/tty.*
/dev/tty.usbmodem101

download code

import motor
import time
import random


def goto(m: motor.Motor, x, vel, accel):
    # print(m.get_states())
    m.set_target_position(x, vel, accel)

    # print(m.get_states())
    # ... wait while not at point:
    while True:
        states = m.get_states()

        # print(states["position"])
        # if states['is_moving'] == 0:
        if not states["is_moving"]:
            break
        # if abs(states["position"] - x) <= 0.01:
        #     break


def goto_all(m1: motor.Motor, m2: motor.Motor, x1, x2, vel, accel):
    m1.set_target_position(x1, vel, accel)
    m2.set_target_position(x2, vel, accel)

    # ... wait while not at point:
    done = False
    while not done:
        states1 = m1.get_states()
        states2 = m2.get_states()
        done = states1['is_moving'] == 0 and states2['is_moving'] == 0


def main():
    # change to the correct serial port
    # m = motor.Motor("COM47")
    m = motor.Motor("/dev/tty.usbmodem101") # =============================== here

    # turns/sec
    vel = 5
    # turns/sec²
    acc = 30

    # 200 steps per turn
    steps_per_unit = 200
    # 30% current
    current = 0.3

    m.set_steps_per_unit(steps_per_unit)
    m.set_current(current)

    goto(m, 2.0, vel, acc)
    time.sleep(0.2)
    goto(m, 0.0, vel, acc)

    m.set_current(0)


if __name__ == "__main__":
    main()

% cd path/to/code/python
% tree
.
├── __pycache__
│   ├── cobs_usb_serial.cpython-312.pyc
│   ├── cobs_usb_serial.cpython-313.pyc
│   ├── motor.cpython-312.pyc
│   └── motor.cpython-313.pyc
├── cobs_usb_serial.py
├── main_test.py
└── motor.py

% python3 main_test.py

Two machines

% ls /dev/tty.*       
/dev/tty.usbmodem101
/dev/tty.usbmodem1101

import motor
import time
import random


def goto(m: motor.Motor, x, vel, accel):
    # print(m.get_states())
    m.set_target_position(x, vel, accel)

    # print(m.get_states())
    # ... wait while not at point:
    while True:
        states = m.get_states()

        # print(states["position"])
        # if states['is_moving'] == 0:
        if not states["is_moving"]:
            break
        # if abs(states["position"] - x) <= 0.01:
        #     break


def goto_all(m1: motor.Motor, m2: motor.Motor, x1, x2, vel, accel):
    m1.set_target_position(x1, vel, accel)
    m2.set_target_position(x2, vel, accel)

    # ... wait while not at point:
    done = False
    while not done:
        states1 = m1.get_states()
        states2 = m2.get_states()
        done = states1['is_moving'] == 0 and states2['is_moving'] == 0


def main():
    # change to the correct serial port
    #m = motor.Motor("COM47")
    m1 = motor.Motor("/dev/tty.usbmodem101")
    m2 = motor.Motor("/dev/tty.usbmodem1101")
    # turns/sec
    vel = 5
    # turns/sec²
    acc = 30

    # 200 steps per turn
    steps_per_unit = 200
    # 30% current
    current = 0.3

    m1.set_steps_per_unit(steps_per_unit)
    m1.set_current(current)
    m2.set_steps_per_unit(steps_per_unit)
    m2.set_current(current)
    goto_all(m1, m2, 2.0, 2.0, vel, acc)
    #goto(m, 2.0, vel, acc)
    time.sleep(0.2)
    goto_all(m1, m2, 0.0, 0.0, vel, acc)
    #goto(m, 0.0, vel, acc)

    m1.set_current(0)
    m2.set_current(0)


if __name__ == "__main__":
    main()