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Build your own machine

Repo
Download from this site

Firmware

Download firmware from repo / from this site

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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

# Check Python version
% python3 --version
Python 3.13.5

# Check pyserial version (if installed)
% python3 -c "import serial; print(serial.__version__)"
3.5

# Install or update pyserial if missing or outdated
% python3 -m pip install --user --upgrade pyserial

# Check cobs version
% python3 -c "import cobs; print(cobs.__version__)"
1.2.1

# Install or update pyserial and cobs if needed
% python3 -m pip install --user --upgrade pyserial cobs

code

Serial port 

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

% ls /dev/cu.*   
/dev/cu.usbmodem101

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

Note

Use /dev/cu. instead of /dev/tty. for USB serial devices on macOS.
/dev/cu.* is non-blocking and safer for direct communication with Arduino.

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")
    # Use /dev/cu.* instead of /dev/tty.* for USB serial devices on macOS.
    # /dev/cu.* is non-blocking and safer for direct communication with Arduino.
    m = motor.Motor("/dev/cu.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()