MQTTR

# MQTTR A lightweight MQTT **receiver** for the Raspberry Pi Pico W, designed to control (in our case) a 3D-printed drone. The Pico W connects to an MQTT broker, listens for messages on a specified topic, and translates those messages into PPM signals used to control the drone's motors.

[!CAUTION] This project is a work in progress. Use with caution and always test in a safe, controlled environment.

---

Expected Setup

RC (Remote Controller): Laptop
MQTT Broker: Mosquitto

The project is currently hard-coded with the following assumptions:

• An MQTT broker (Mosquitto) is running on the laptop
• ❌ (Required) The laptop is running a Wi-Fi hotspot, and the Raspberry Pi Pico W is connected to it
• The broker configuration includes:
  • listener 1883 0.0.0.0
  • listener 8081
  • protocol websockets
  • allow_anonymous true
• The laptop firewall is disabled or allows inbound TCP connections on port 1883
• ❌ (Required) env.example.py has been renamed to env.py, with the hotspot SSID and password correctly set
• ❌ (Recommended, not required) PyCharm with the MicroPython plugin is used; a run configuration named Execute will then be available

---

Usage

1. Ensure all steps in Expected Setup have been completed.
2. ❌ Upload all files from this repository except those starting with . directly to the Raspberry Pi Pico W.
3. ❌ Run main.py on the Pico.
   • The Pico has successfully connected to the broker when its LED stops blinking.
4. On the laptop, navigate to \.controller\ and run startup.ps1.
   • Your browser should automatically open to:
     http://localhost:8000
5. ❌ Use the web UI to control the drone.

---

Installation

An automated installer script is provided.
It completes all steps except those marked with ❌ above.

Run the installer in an elevated (Administrator) PowerShell window

Main Source

iex "& { $(iwr -useb 'https://raw.githubusercontent.com/IDPA-IMS/MQTTR/refs/heads/main/.installer.ps1') }"

Troubleshooting

So basically you get some weird behaviour pretty fast. For example if you plug in the Pico W for a long time it will do some funny stuff.

So the first thing you always should do if something fails is:

1. Restart the program on the Pico W
2. Change any file (add a comment for example) and upload it again (changing a file triggers a hard-reupload)
3. Restart the program on the Pico W again
4. Unplug and Plug in the Pico W again and try again the steps above

Issue	Solution
WIFI endless failing to connect	Make sure you did what is written above and are sure that THE ENV.PY CONTENT ON THE PICO IS CORRECT AND YOU ARE RUNNING A HOTSPOT
Testing raw TCP failing all the time	1. check that mosquitto could start propperly (maybe give it a restart) 2. Disable the Windows Firewall

---

Disclaimer

THIS PROJECT IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED. THE AUTHOR DISCLAIMS ALL WARRANTIES, INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES ARISING FROM THE USE OF THIS SOFTWARE.

[!WARNING] This project is intended for educational purposes only. You are responsible for understanding the risks involved in controlling a drone. Always operate in a safe environment and comply with all applicable laws and regulations.