Labs · Motion control

Pi Pico W stepper rotation axis (stepper_controller.PicoStepperController)

Pi Pico W stepper rotation axis (stepper_controller.PicoStepperController), adapted from burhankarahasan/thorlabs-pico. It reads current_rps and position_steps; sets target_rps; runs stop_motion, enable_motor, disable_motor and set_ramp_rate. stop_motion: stop all motion on the resource with a declared deceleration profile and report the stopping position. This capability is always cancellable=false and is exempt from rate limiting. A hardware driver: the market serves its fake backend, so no instrument is needed.

hardwareRisk R1MITcontract_checkedserved on the fake backend
openai4s lab add labs/burhankarahasan__thorlabs-pico

Install

Three ways to run this device. Each one serves its fake backend: no instrument, no simulator install and no upstream checkout.

OpenAI4S (one command)

shell
openai4s lab add labs/burhankarahasan__thorlabs-pico

Installs the device into the OpenAI4S Lab on its fake backend and starts it. First time? See setup below.

Or, in the workbench, open the Lab tab → Market → Install.

Standalone MHS endpoint

shell
git clone --depth 1 https://github.com/PKU-YuanGroup/OpenMHS.git && cd OpenMHS
PYTHONPATH=MHS/sdk/src python3 -m mhs serve labs/burhankarahasan__thorlabs-pico --port 7400
# in a second terminal, from the same directory:
PYTHONPATH=MHS/sdk/src python3 -m mhs describe --endpoint http://127.0.0.1:7400

Serves the device as an MHS endpoint on port 7400 from an OpenMHS clone (Python 3.10 or later, standard library only); describe prints what it offers.

Any MCP host (Claude Desktop, Cursor, …)

mcp configuration
{
  "mcpServers": {
    "thorlabs-pico": {
      "command": "python3",
      "args": [
        "-m",
        "mhs",
        "serve",
        "labs/burhankarahasan__thorlabs-pico",
        "--mcp"
      ],
      "env": {
        "PYTHONPATH": "/path/to/OpenMHS/MHS/sdk/src"
      }
    }
  }
}

Add this server to the host's MCP configuration and replace /path/to/OpenMHS with the path of your OpenMHS clone. The host starts the server and talks to it on stdin and stdout.

What it does

Measures

  • current_rps
  • position_steps

Adjusts

  • target_rps

Actions

stop_motion
Stop all motion on the resource with a declared deceleration profile and report the stopping position. This capability is always cancellable=false and is exempt from rate limiting.
enable_motor
Enable the stepper motor driver (the native ENABLE)
disable_motor
Disable the stepper motor driver; the upstream docstring says this cuts power (DISABLE)
set_ramp_rate
Set the acceleration/deceleration rate in steps/sec^2 (the native RAMP)

Names as the driver declares them. Units, limits and the safety declaration are in the package's REFERENCE.md.

First-time setup

The OpenAI4S workbench with the OpenMHS lab, from a source checkout:

shell
# OpenAI4S workbench with the OpenMHS lab (source checkout)
git clone --recursive https://github.com/PKU-YuanGroup/OpenAI4S.git
cd OpenAI4S && ./setup.sh && source .venv/bin/activate
openai4s lab add labs/burhankarahasan__thorlabs-pico
openai4s serve        # open the Lab tab

The standalone endpoint and the MCP server need only an OpenMHS clone and Python 3.10 or later. More in the market's getting-started guide and on the OpenAI4S host page.

Source and evidence

Pinned commit
91898e3a55a9
Licence
MIT
Stars
0
Evidence
contract_checked on the fake backend
Backends
fake, hardware

The driver package MHS/drivers/labs/burhankarahasan__thorlabs-pico wraps the upstream code at the pinned commit. Its REFERENCE.md documents the full contract: every value, action, unit, limit and the safety declaration.