Raspberry Pi PicoW + LeRobot SO-ARM100 controlled via a webpage/mqtt/openai

Developer AdrianCX released picohive-robotarm, an open-source firmware that runs a standalone Raspberry Pi Pico W or Pico 2 W controller for LeRobot SO-100/SO-101 arms, controllable over Wi-Fi through a built-in web page, MQTT, or an OpenAI Responses API-compatible endpoint. The firmware builds via os/build_via_podman.sh for pico_w, pico2_w, or a Linux simulation with simulated servos, and the developer reports 150KB of free heap in the worst case on the Pico. Setup follows LeRobot's procedure: assign servo IDs at 115200 baud, calibrate joint limits from the web page, and map 3D positions so the arm knows orientation before sending targets.

Standalone Raspberry Pi Pico W / Pico 2 W controller for an SO-101 / SO-100 https://github.com/TheRobotStudio/SO-ARM100 arm Can control over WiFi via an internal Web Page, MQTT or openAI response API compatible remote\ Video: https://www.youtube.com/shorts/e Y3U83MK2A https://www.youtube.com/shorts/e Y3U83MK2A I had an RC car and a LeRobot SO-ARM100 and wanted to see if I can combine them and use an LLM to control... The arm is drawn in 3D from what the servos report; click a dot to put a target down, Go or Enter sends the jaws there. | Calibration | AI | Drive | |---|---|---| - Calibration : set up limits for joints so arm doesn't self destruct... don't ask - 3D mapping : tell robot which way is left or up - Poses : various poses described for openAI LLM knowledge base - AI : chat box with status responses. The microphone needs https - Drive : Virtual joystick to control the wheels, or you can connect a gamepad 1. Picohive optional - for Debug logs and OTA updates Add Device on picohive https://picohive.com generate the UUID, MQTT password and log key, pick a name Open the device, go to Device Config , press Export and copy the line for step 4 below 2. OpenAI optional - for AI chat box An API key and a model ex: gpt-6.1-sol on a server that has responses API with storage 1. Flash a pico, it starts as access point picow config / randompassword ...ultra secure password... 2. Connect to the access point, the page opens by itself, if not, use http://192.168.4.1 http://192.168.4.1 3. Configure wifi and a user/pass for the web ui 4. Optional : 4.1. Remote server enter line from picohive for logging/OTA/crash reporting 4.2. OpenAI enter the URL, key, model and prompt 5. Reboot - joins your wifi, you can access via its new IP now find it in picohive logs or on router 6. Reconfigure any time from its new ip address Tip If you need to wipe, just use the universal flash nuke.uf2 https://github.com/Gadgetoid/pico-universal-flash-nuke to wipe the flash then re-flash the firmware This follows LeRobot, in short: 1. Add servos one at a time to pico to set their IDs to not overlap and baud rate to 115200, 1M was too much for my setup with 1K resistor 2. Build up the arm and connect things 3. Calibrate from web page just press the calibrate and move the arm by hand so it learns limits 4. Go to 3D model and map some positions so it knows left from right and up from down... git clone --recursive https://github.com/AdrianCX/picohive-robotarm.git cd picohive-robotarm os/build via podman.sh pico2 w or pico w Flash build/<board /robotarm.uf2 Later updates for OTA need the encrypted file robotarm.uf2.encrypted Before you build your own, create your own OTA keys and certificate, as described in os/docs/ota.md https://github.com/AdrianCX/picohive-robotarm/blob/main/os/docs/ota.md . The HTTPS certificate is util/make cert.sh <address . The same app builds on Linux with simulated servos Useful to work on web page with valgrind and gdb os/build via podman.sh linux build/linux/robotarm os/run via podman.sh http://localhost:8080, https://localhost:8443 os/run via podman.sh --valgrind or --gdb 2026-10-25 13:52:12 192.168.100.69 657 app build/pico w/robotarm version 1.0 os b697060-dirty buildid db40f1ac39e2b3ee3d07d2199aa628118cf588b3 Heap 12308/223652 Free 211344 MinFree 151552 LargestFree 192458 Stack 4236/16384 lastRestartReason reboot command There's quite a lot of free memory on pico even in worst case 150KB , stack usage is reasonable Wiring defaults in src/config/general config.h , change them there if you wire it differently : - Servo bus: GPIO 0 uart0 tx through 1k, and GPIO 1 rx , both onto the servos' data wire, 115200 baud ARM BAUDRATE - Servos: 12V and ground straight from the supply, the Pico's ground joins them - Front DRV8833: left front on GPIO 17/16, right front on GPIO 18/19 - Rear DRV8833: left rear on GPIO 15/14, right rear on GPIO 12/13 forward/back of each - GPIO 20 to both drivers' sleep EEP , held high - Pico: 5V from a buck converter into VSYS The bus is half duplex - one data wire shared by every servo. The pico's pins are 3.3V: check a servo's data wire idles at or below that, or put a level shifter in between. The Waveshare bus servo driver board does all of this already, and plugs into the same two pins. Two pins of one motor share a PWM slice gpio/2 % 8, even A, odd B , keep that if you move them. MOTOR PWM 1 drives the pins as PWM, 0 is on/off. The diagram is generated: python3 docs/pictures/wiring.py docs/pictures/wiring.svg Arm: - SO-101 https://github.com/TheRobotStudio/SO-ARM100 printed parts, or a kit - 6x STS3215 servos, 12V - 2 batteries 26650 - Printed parts for this build in stl/ Electronics: - Raspberry Pi Pico 1 W - you should use Pico2 to add a camera later - 5V buck converter for Pico mini360 is fine - 1k resistor - 2x DRV8833 motor driver https://www.tinytronics.nl/en/mechanics-and-actuators/motor-controllers-and-drivers/stepper-motor-controllers-and-drivers/drv8833-bipolar-stepper-motor-and-dc-motor-motor-controller Chassis optional : - 4x DC motors and wheels AGPL-3.0-or-later for this app. The os/ submodule is MPL-2.0, see its LICENSE.