LED SIGN – Raspberry Pi Pico W (MicroPython)

LED Sign is a Raspberry Pi Pico W project that

1. reads the distance to an object (ultrasonic sensor) and
2. changes the LED strip color based on that distance,
3. and additionally exposes a small Web UI + REST API to control the LEDs.

Hardware

• Raspberry Pi Pico W
• Individual addressable RGB LED strip (WS2812/NeoPixel compatible)
• Ultrasonic distance sensor (e.g. HC-SR04 compatible)

Wiring circuit overview (schematic)

Quick start

1. Flash MicroPython onto the Pico W.
2. Copy settings.example.py and rename it tosettings.py.
3. Important: Edit settings.py and set your Wi-Fi and pins.
4. Upload the files to the Pico W and reboot it. This can be done in two ways:
   • Execute py .\deploy.py -a -s -r -l. This will copy all necessary files (including settings.py), reboot the Pico W and start reading the serial output.
   • Copy the necessary files manually to the Pico W and reboot it.
5. The IP-address given to the Pico W will be printed on the serial console.

How deploy.py works

deploy.py is a helper script to copy the necessary files to the Pico W and optionally reboot and read logs.

It supports the following flags:

• -h to show the help message
• -p port to specify the serial port (e.g. COM3, standard: auto-detect)
• -a to copy all necessary files
• -f filename filename2 to copy the given files
• -d dirname dirname2 to copy the given directories
• -s to copy settings.py
• -r to reboot the Pico W after deployment
• -l to start reading the serial output (logs) after deployment

Features

You can change the colors of the LED strip through two different HMIs:

1. Web UI at http://<pico-ip>/
2. Ultrasound sensor

Ultrasound Sensor – Distance color mapping

The measured distance (cm) of the ultrasound sensor maps to different colors:

• < 3 blink + OFF
• 3..6 RED
• 6..9 ORANGE
• 9..12 YELLOW
• 12..15 GREEN
• 15..18 BLUE
• 18..21 PURPLE

Web UI

After the Pico is connected to Wi-Fi, open:

• http://<pico-ip>/

The UI offers:

• RGB color picker
• OFF button
• Effects: Breath, Cycle, Lottery, Candy Tornado

Note: Any change of color, which is made either through the Web UI or the ultrasound sensor, cancels the currently running LED animation task (effect).

How the project works

• On boot (boot.py) the Pico tries to connect to Wi-Fi and prints the assigned IP
  • If Wi-Fi is not available, it keeps retrying asynchronically
  • The ultrasound sensor will still be available
• Also on boot, the homepage with the current version is generated:
  • lib/static/index.html contains a {{VERSION}} placeholder
  • boot.py replaces it with the version from pyproject.toml
  • output is written to lib/generated/index_with_version.html
• In main.py the ultrasonic distance loop starts and updates the LEDs continuously based on the measured distance
• The web server is started on port 80 (if a Wi-Fi connection is available)

Static IP recommendation

For a smoother experience, reserve a static lease for the Pico in your router/DHCP settings (recommended) or implement a fixed IP configuration in MicroPython.

Troubleshooting

• Web UI shows 404 / blank page: ensure boot.py ran and created lib/generated/index_with_version.html and that lib/static/ exists.
• Cannot connect to Wi-Fi: re-check SSID/Password in settings.py. The device prints connection attempts and errors on the serial console.
• Webserver not reachable: verify the printed IP and that your client is in the same network. Server runs on port 80.
• LEDs stay off: verify NumLEDs, LEDPin, power supply and LED type.
• Distance colors keep updating: the distance loop runs continuously. Verify that the ultrasound sensor points into a direction that has no object in its way (at least 25 cm).

Contributing / Support

• Feature request: contact one of the collaborators
• Bug report: open an issue or contact SirDaywalker

License

MIT