Control an IR Remote AC Using ESP32 and Home Assistant

Ever wished your dumb air conditioner could join your smart home party? I did—especially during a heatwave when I realized I’d left the AC on full blast while away. Enter the ESP32, a $5 microcontroller that (with some tinkering) can emulate your AC’s IR remote and integrate it into Home Assistant. Here’s how I did it.

What You’ll Need

• Hardware:
  • ESP32 board (any variant with IR send/receive, like the ESP32-C3)
  • IR receiver/sender module (e.g., VS1838B + IR LED)
  • Breadboard and jumper wires
  • USB cable for power/flashing
• Software:
  • Home Assistant (installed and running)
  • ESPHome (via Home Assistant Add-on)
  • IR remote control app (like IRdroid for capturing raw codes)

Step 1: Capture Your AC’s IR Codes

First, we need to “learn” the IR signals from your remote.

1. Wire the IR receiver to the ESP32:
   • Connect the receiver’s VCC to 3.3V, GND to GND, and OUT to GPIO pin 4 (or any free pin).
2. Flash ESPHome with IR capture:

   # Example ESPHome config for IR capture
   esphome:
     name: ir_capturer
   esp32:
     board: esp32dev
   wifi:
     ssid: "YOUR_WIFI"
     password: "YOUR_PASSWORD"
   logger:
   api:
   remote_receiver:
     pin: GPIO4
     dump: raw
   

3. Upload and monitor logs:
   • In ESPHome, click Install → Upload Serial. Point your AC remote at the receiver and press a button (e.g., “Power On”).
   • You’ll see raw code arrays like:

     Received Raw: -1234, 567, -890, ...
     

4. Repeat for all commands (Power Off, Temp ±, Fan Speed, etc.).

Step 2: Emulate IR Signals with ESP32

Now, reconfigure the ESP32 to send IR signals.

1. Rewire for IR transmission:
   • Replace the receiver with an IR LED: anode to GPIO5 (via a 100Ω resistor), cathode to GND.
2. Update ESPHome config:

   remote_transmitter:
     pin: GPIO5
     carrier_duty_percent: 50%
   climate:
     - platform: infrared
       name: "Living Room AC"
       supports:
         - heat
         - cool
       codes:
         # Paste raw codes from Step 1
         power_on: "raw:-1234,567,-890,..."
         power_off: "raw:-4567,890,-123,..."
         cool_28c: "raw:-7890,123,-456,..."
   

3. Flash and validate:
   • The ESP32 should now respond to Home Assistant climate commands by blasting IR signals at your AC.

Step 3: Integrate with Home Assistant

After flashing:

1. Auto-discovery: ESPHome should automatically add the climate entity to Home Assistant.
2. Create a dashboard:

   # Example Lovelace card
   type: thermostat
   entity: climate.living_room_ac
   

3. Automations (Bonus!):

   # Turn off AC when no one’s home
   automation:
     trigger:
       - platform: state
         entity_id: person.your_name
         to: "not_home"
     action:
       - service: climate.turn_off
         target:
           entity_id: climate.living_room_ac
   

Troubleshooting

• No IR signal detected?
  • Check wiring and GPIO pins.
  • Use a phone camera to verify the IR LED is blinking (it’ll show faint purple light).
• Partial commands?
  • Ensure raw codes are captured fully. Some remotes send multiple signals per press.
• Home Assistant not seeing the device?
  • Restart ESPHome and check logs → esphome in Home Assistant.

FAQ

Q: Can I control multiple ACs?
A: Yes! Use separate GPIO pins/IR LEDs and duplicate the climate block in ESPHome.

Q: Will this work with any IR AC?
A: Most standard IR-controlled ACs are supported. Exceptions: Proprietary protocols (e.g., some Daikin models).

Q: How’s the range?
A: ~5 meters. For longer distances, use multiple ESP32s or a stronger IR LED.

Next Steps

• Add temperature sensors (like the Xiaomi Mijia) for feedback loops.
• Explore Zigbee2MQTT for other devices (tutorial here).

Now go forth and never sweat over a forgotten AC again! 🎉