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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-DevKit board: Buy it here
    • IR receiver/sender module VS1838B + IR LED: Buy it here
    • Breadboard and jumper wires
    • USB cable for power/flashing
  • Software:
Pro Tip: Test your IR LED before wiring—some have narrow angles. I spent 30 minutes debugging before realizing mine was pointed at the ceiling!

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

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