garaged

A tiny Wi-Fi garage door opener built on an ESP32. Tap a button on your phone to open the door and check whether it's open or closed. Your existing wall button keeps working exactly as before.

The whole thing costs about £25–35, takes an afternoon to build, and stays entirely on your local network — nothing is exposed to the internet.

How it works

Your garage opener's wall button just shorts two low-voltage wires together for a moment. This project wires a relay in parallel with that button, so when the ESP32 pulses the relay it's electrically identical to a button press. A magnetic reed sensor on the door tells you whether it's open or closed.

The ESP32 runs a small HTTP server on your Wi-Fi. Your phone sends it an authenticated request (via an iOS Shortcut or an Android app), the relay fires, the door moves.

  Phone (Shortcut)  --Wi-Fi-->  ESP32  --> Relay --> Garage opener button terminals
                                  |  ^
                          reed sensor (existing wall button stays wired here too)

The API is deliberately minimal:

Method & path	Auth	Does
POST /trigger	Bearer token	Pulses the relay for ~500ms (one door press)
GET /status	none	Returns `{"door":"open
GET /	none	Plain-text health page for a browser

The relay is driven inactive on boot and auto-released after the pulse, so a crash, reboot, or stuck request can never hold your garage button down.

What's in this repo

garage_esp32.ino    Firmware (Arduino core for ESP32)
case/               3D-printable enclosure (STL)
  base.stl          Box that holds the ESP32 + relay
  lid.stl           Snap-on lid
  backing_plate.stl Wall mount
LICENSE             MIT

Shopping list

Prices are UK/GBP. If you already own a USB charger and cable and skip the enclosure, you can do this for well under £15.

Core parts

Item	What to get	~£	Notes
ESP32 board	ESP32-WROOM-32 DevKit, 38-pin, USB-C, pre-soldered	7–11	A 2–3 pack gives you a spare. HiLetgo / ELEGOO / AZDelivery are fine.
USB power	Any 5V phone charger (1A+) + a data USB-C cable	0–5	Powers the ESP32. Never wire the ESP32 to mains directly — it's a 5V device.
Relay module	1-channel 3V/3.3V, low-level trigger	3–4	Powered and triggered from the ESP32's 3.3V pin. Avoid 5V-only boards — they often won't switch from 3.3V.
Reed door sensor	Wired magnetic reed switch, NC (normally closed)	4	For open/closed status. Search "wired magnetic reed switch NC door sensor".
Jumper wires	Female-to-female Dupont, 20cm multipack	3	You'll use 5+.
Two-core wire	Bell wire / alarm cable ~0.5mm²	4	For the relay-to-opener run. Carries a signal, not power.

Optional

Item	What to get	~£
Enclosure	Print the files in case/, or an off-the-shelf ~100mm ABS box	0–5

Before you order

1. Pre-soldered pins — confirm the ESP32 listing says the header pins are already soldered, so you can plug jumpers straight in.
2. NC sensor — the status logic assumes a normally-closed reed sensor. If you end up with an NO one, you don't rewire — just flip INVERT_SENSOR in the firmware (see below).

Wiring

ESP32 → relay module:

ESP32 pin	Relay pin
3.3V	VCC
GND	GND
GPIO23	IN

Assumes a 3V/3.3V relay board. If you use a 5V-coil board instead, wire VCC to the ESP32's 5V (VIN) pin — but a 3.3V-triggered board is recommended.

Relay → garage opener: use the COM and NO output terminals so the circuit is open by default and only closes on a pulse. Wire them to the same two low-voltage terminals your wall button uses. Polarity doesn't matter.

Relay COM  ->  one garage button terminal
Relay NO   ->  other garage button terminal

Your existing wall button stays connected — the relay sits in parallel with it on the same two terminals. Either one triggers the door; neither interferes with the other.

Reed sensor → ESP32: one wire to GPIO22, the other to GND (polarity doesn't matter). Mount the two halves so they're aligned/touching when the door is closed.

Full wiring diagram

                    ESP32 WROOM-32 DevKit
                 ┌───────────────────────────┐
   USB-C  <──────┤ USB-C (5V from USB plug)   │
                 │  3.3V ─────────────┐       │
                 │  GND ──────────┐   │       │
                 │  GPIO23 ───┐   │   │       │
                 │  GPIO22 ─┐ │   │   │       │
                 │  GND ──┐ │ │   │   │       │
                 └────────┼─┼─┼───┼───┼───────┘
                          │ │ │   │   │
            reed sensor   │ │ │   │   │
         ┌──────┐         │ │ │   │   │
         │ magnet on door │ │ │   │   │
         │ switch on frame│ │ │   │   │
         │      ├─────────┘ │ │   │   │
         │      ├───────────┘ │   │   │
         └──────┘             │   │   │
                          ┌───┴───┴───┴────┐
                          │   IN  GND  VCC │   Relay module
                          │                │
                          │  COM   NO   NC │
                          └───┬────┬───────┘
                              │    │      ┌─────────────────────┐
                              │    └──────┤ Garage opener        │
                              └───────────┤ button terminals A/B │
        Existing wall button ────────────┤ (same terminals A/B) │
        (leave connected!)  ─────────────┤                      │
                                          └─────────────────────┘

Flashing the firmware

You flash the ESP32 once from a computer over USB-C. After that it runs on its own.

1. Install the Arduino IDE — https://www.arduino.cc/en/software.
2. Add ESP32 board support. In Settings → Additional Boards Manager URLs add:

   https://espressif.github.io/arduino-esp32/package_esp32_index.json
   

   Then Tools → Board → Boards Manager, search esp32, and install "esp32 by Espressif Systems".
3. Open garage_esp32.ino and edit the values at the top:
   • WIFI_SSID / WIFI_PASSWORD — your Wi-Fi.
   • AUTH_TOKEN — a long random secret. Generate one with openssl rand -hex 24 and keep it private.
   • Leave HAS_SENSOR = true if you're fitting the reed sensor.
   • (Optional) set USE_STATIC_IP = true and fill in addresses for a fixed IP, or leave it and reserve the IP in your router later.
4. Select the board & port. Plug in the ESP32, choose Tools → Board → ESP32 Arduino → "ESP32 Dev Module", then pick the new port under Tools → Port (/dev/cu.usbserial-… on Mac, COM3 on Windows). No port showing? Install the USB driver for your board's chip — CP2102 (Silicon Labs CP210x) or CH340.
5. Upload. Click the upload arrow. If it stalls at "Connecting…", hold the board's BOOT button for a couple of seconds, then release.
6. Find its IP. Open Tools → Serial Monitor at 115200 baud and press the board's EN/RST button. You'll see:

   Connected. IP address: 192.168.1.xx
   

   Write this down — your phone shortcuts need it. Visit http://THAT_IP/ in a browser on the same Wi-Fi to confirm the server is up.

Fitting & testing the door sensor

Mount the switch body to the fixed frame and the magnet to the moving door, within ~15–20mm of each other when the door is fully closed.

Then test:

1. With the door closed, visit http://YOUR_ESP32_IP/status → should return {"door":"closed", ...}.
2. Open the door and refresh → should flip to "open".
3. Reads backwards? Set INVERT_SENSOR = true in the firmware and re-flash. (This also handles an NO sensor with no rewiring.)

Operating it from your phone

iPhone (Shortcuts)

Open Garage (the trigger):

1. Shortcuts → + → add Get Contents of URL.
2. URL http://YOUR_ESP32_IP/trigger, tap Show More, set Method: POST.
3. Add a header: key Authorization, value Bearer YOUR_TOKEN (the same token from the firmware — mind the word Bearer and the space).
4. Name it "Open Garage", then Share → Add to Home Screen for a one-tap button, or trigger it with "Hey Siri, Open Garage".

Garage Status (read-only, no token):

1. Get Contents of URL → http://YOUR_ESP32_IP/status (GET).
2. Get Dictionary Value → key door.
3. Show Result. Tapping it shows "open" or "closed".

Want a single shortcut that checks status and asks for confirmation before closing? It's a few extra steps around the two above — open an issue if you'd like a worked example.

Android

Use the free HTTP Shortcuts app (or Tasker):

• Trigger: POST to http://YOUR_ESP32_IP/trigger with header Authorization: Bearer YOUR_TOKEN.
• Status: GET http://YOUR_ESP32_IP/status, display the door value.
• Add either as a home-screen widget.

Keep the IP from changing

A router reboot can hand the ESP32 a new IP and break your shortcuts. Pick one:

• DHCP reservation (easiest): in your router admin, find the ESP32 and reserve/bind its current IP to its MAC address. No firmware change.
• Static IP: set USE_STATIC_IP = true in the firmware with addresses that match your network (outside the DHCP range) and re-flash.

First run & safety

1. Test the relay before wiring it to the opener. Power the ESP32 and hit /trigger while listening — you should hear one click and release. Confirm it's a single momentary pulse.
2. Only then connect COM/NO to the opener terminals.
3. Test the door from a safe spot where you can see it move and stop.
4. Confirm your existing wall button still works — it should, unchanged.
5. Never defeat your opener's built-in safety features (auto-reverse, photo-eye sensors). Keep them all intact.

Troubleshooting

Symptom	Fix
Relay clicks but door doesn't move	Check COM/NO are on the same two opener terminals the wall button uses.
Relay never clicks, or clicks inverted	Flip RELAY_ACTIVE_LOW in the firmware and re-flash.
Status reads backwards	Flip INVERT_SENSOR (or confirm the sensor is NC) and re-flash.
Phone shortcut does nothing	Phone must be on your home Wi-Fi (not mobile data / guest network); check the IP is current.
401 unauthorised	Token mismatch — the header must be exactly Bearer <your token>.
No serial port when flashing	Install the CP2102 or CH340 USB driver for your board.

Using it away from home

This setup is local-only by design, which is the safest default. Do not port-forward the ESP32 to the internet. To reach it remotely, put both your phone and a small always-on device at home on a Tailscale network — the same shortcuts then work from anywhere — or broker the connection through Home Assistant.

Security notes

• /trigger requires a bearer token; /status and / are read-only and open.
• Traffic is plain HTTP on your LAN — fine for a local-only device, but don't expose it publicly.
• Keep your AUTH_TOKEN out of screenshots and public forks.

Contributing

Issues and pull requests are welcome — improvements to the firmware, the case, or these instructions especially. If something in the setup tripped you up, that's worth an issue too.

License

MIT.