WLAN Gate Opener

This is a personal project with the goal of opening a gate from the phone.

• Components
• Setup
  • Setup IDE
  • Setup MicroPython
  • Setup Project on Pico
• Circuit
  • Circuit Diagram
  • Pico W pinouts
• How the final result looks like in real life

Components

• MOSFET -- IRLI540NPbF
• Relay -- LMR2-3D

  Most likely not needed -- MOSFET can be used instead but I like the audio feedback it gives.

  Only one side is used so LMR1 is totally fine, this was just locally available.

• Microcontroller -- Pico W
• Resistors:
  • 220 Ω
  • 10 kΩ
• Remote that opens the gate (mine operates on a 12V battery)

Setup

Setup IDE

I decided to use Visual Studio Code to develop this project but Thonny is a good alternative.

• install Visual Studio Code
• install reccomended extensions, can be found in .vscode\extensions.json
  • the most important one is the MicroPico extension

More information can be found in paragraph 4.2 of Raspberry Pi Pico-series Python SDK

Setup MicroPython

Setup MicroPython on raspberry pi Pico

• download MicroPython (version used is v1.25.0)
  • the latest from https://micropython.org/download/rp2-pico-w/rp2-pico-w-latest.uf2
  • or use the one I used for this project dev\RPI_PICO_W-20250415-v1.25.0.uf2
• program the Pico
  1. Push and hold the BOOTSEL button while connecting your Pico with a USB cable to a computer. Release the BOOTSEL button once your Pico appears as a Mass Storage Device called RPI-RP2.
  2. Drag and drop the MicroPython UF2 file onto the RPI-RP2 volume. Your Pico will reboot. You are now running MicroPython.
  3. Access the REPL via USB Serial.

More information can be found on Drag-and-Drop MicroPython -- Raspberry Pi Documentation

Setup Project on Pico

Get the project running on pico

• copy env.py.example to src\env.py
  • on windows use cp .\env.py.example .\src\env.py
• populate required fields with information
  • SSID with the name of the Wi-Fi you want to connect to
  • WLAN_PASS with the password for that connection
  • SIGNAL_DURATION with how long you want the remote to be on in milliseconds
• upload project to Pico
  • open command palette (F1 or Ctrl+Shift+P) in vscode
  • then MicroPico: Upload project to Pico
  • alternative is to use rshell

MicroPython automatically starts main.py on device start.

see more -- MicroPython - Reset and Boot Sequence

Circuit

Circuit Diagram

Picture of the circuit that is used in this project

Pico W pinouts

Pinouts used in this project:

• 3V3(OUT) (36) -- powering the relay MOSFET circuit
• GND (38) -- final point of the relay MOSFET circuit
• GP15 (20) -- driving the MOSFET's gate
• GND (3) -- final point of the circuit that controls the MOSFET

Pico W pinouts, source -- https://www.raspberrypi.com/documentation/microcontrollers/images/picow-pinout.svg

How the final result looks like in real life