PicoBot Robot — Competition Setup – RoboSteam Competitions

Raspberry Pi Pico 2 W robot code for the PicoBot competition server at https://limetka.fei.tuke.sk/picobot-contest/.

Repository layout

main.py                   Entry point — imports and runs picobot_main
PicoBot/
  picobot_config.py       WiFi + server credentials (EDIT THIS FIRST)
  picobot_main.py         Main loop: web server + periodic status reporting
  picobot.py              PicoBot class: motors + arm (with no-hardware stub)
  picobot_motors.py       Motor driver (PCA9685 over I2C0)
  picobot_arm.py          Arm servo driver (PCA9685 over I2C1)
  pca9685.py              Low-level PCA9685 PWM chip driver
catch_boot.py             Upload tool: catches Pico boot window and uploads all files
upload_to_second.py       Same as catch_boot.py but waits for a specific replug event

Hardware

Board: Raspberry Pi Pico 2 W (RP2350)
Firmware: MicroPython v1.28.0 for RPI_PICO2_W (download)
Motor board: PCA9685 PWM chip on I2C0 (GP20 SDA / GP21 SCL)
Arm board: PCA9685 PWM chip on I2C1 (GP2 SDA / GP3 SCL)
Testing without hardware: works — _NullHardware stub is used automatically

Quick start

1. Flash MicroPython

Hold BOOTSEL on the Pico and plug in USB — it mounts as RPI-RP2350.
Copy micropython-pico2w.uf2 onto the drive.
Pico reboots into MicroPython automatically.

2. Configure credentials

Edit PicoBot/picobot_config.py:

WIFI_SSID     = 'YourNetworkName'
WIFI_PASSWORD = 'YourPassword'
REPORT_URL    = 'https://limetka.fei.tuke.sk/picobot-contest/picobot/status'
REPORT_AUTH   = 'your-competition-bearer-token'
REPORT_DELAY  = 2      # seconds between status POSTs
SERVER_ENABLE = True
SERVER_BRAKE  = False  # True = motors locked unless competition is running

Get the bearer token from the competition page (/picobot-contest/competition → Token field).

3. Upload code

See UPLOAD_GUIDE.md for full details.

Short version — run from this directory:

python3 catch_boot.py
# then unplug and replug the Pico

The script catches the 1-second boot window before main.py runs and uploads all seven files over raw REPL.

Competition server protocol

Every REPORT_DELAY seconds the robot POSTs:

{
  "mac":        "aa:bb:cc:dd:ee:ff",
  "ip":         "192.168.1.42",
  "servo_base": 90,
  "servo_arm":  90,
  "servo_claw": 90,
  "uptime_ms":  12345
}

with Authorization: Bearer <token>.

The server returns a single integer:

Value	`competition_ready`	`competition_running`
0	False	False
1	True	False
3	True	True

Verifying the robot is connected

# Dashboard shows all registered robots
curl https://limetka.fei.tuke.sk/picobot-contest/

# Test endpoint with your token
curl -X POST https://limetka.fei.tuke.sk/picobot-contest/picobot/status \
  -H "Authorization: Bearer <token>" \
  -H "Content-Type: application/json" \
  -d '{"mac":"aa:bb:cc:dd:ee:ff","ip":"1.2.3.4","servo_base":90,"servo_arm":90,"servo_claw":90,"uptime_ms":1000}'
# Should return: 3 (if competition running) or 1 (ready) or 0