IoT·May 8, 2026

Universal IR Gree AC Remote

A small ESP32 board that pretends to be a Gree AC remote — control the AC from a browser on the same Wi-Fi.

Overview

Our Gree AC remote went missing sometime last summer, and instead of buying another one I decided to build a replacement that I could actually improve later. The device is an ESP32 board with a few IR LEDs, an IR receiver for testing, a couple of buttons and a tiny status LED. It hosts a small web page on the local network that looks like a real Gree remote — temperature, mode, fan, swing, sleep, the whole thing. Press a button in the browser and the firmware translates the full remote state into the right IR frame and blinks it at the AC. The interesting part was not just making an IR LED flash; it was making the whole thing feel like a finished product. I designed a custom PCB for it, watched the 3D preview a hundred times to catch mistakes, then sent it to fabrication and soldered it up at home.

Specifications

RoleProduct designer, firmware developer, and PCB designer

MicrocontrollerESP32-WROOM-32

SensorsIR receiver

ModulesIR LED transmitterAMS1117 3.3V regulatorUSB power inputTactile buttonsStatus LEDs

ProtocolsWi-FiHTTPInfrared remote protocolGPIO

Tech tagsESP32InfraredWi-FiWeb UIPCB DesignGree AC

Architecture

Browser UI sends commands to the ESP32 web server. Firmware converts the command state into IR frames, drives the IR LED transmitter, and reports status back through the local interface. The PCB integrates power, MCU, IR, indicators, and connectors into a compact remote node.

Schematics

ESP32 IR remote schematic — Complete schematic for the ESP32 IR remote controller.

PCB layout

ESP32 IR remote PCB render — 3D PCB render with ESP32 module, buttons, connector, and IR hardware.

Manufactured PCB

Bare ESP32 IR remote PCB — Bare fabricated PCB before component assembly.

Project photos

Powered ESP32 IR remote board — Powered board test from wall adapter.

IR LED receiver prototype — Separate IR LED and receiver prototype module.

Gree web remote interface — Local browser interface styled as a Gree AC remote.

Videos

Implementation details

Firmware

Firmware hosts a local browser control panel, maps UI actions to Gree AC IR frames, drives the IR LED output, and reads button/receiver input for testing and feedback. The interface supports AC-like controls such as power, mode, fan, temperature, swing, timer, display, light, turbo, sleep, eco, and Wi-Fi toggles.

PCB

Custom ESP32 PCB designed from schematic to 3D render and fabricated prototype. The board includes the ESP32 module, regulator, USB input, IR output stage, receiver connection, user buttons, and indicator LEDs.

Power

Powered from USB or a wall adapter with onboard 3.3 V regulation for the ESP32 and support circuitry.

Components / BOM

ESP32-WROOM-32 module, IR LED, IR receiver module, AMS1117-3.3 regulator, USB connector / power input, Tactile push buttons, Status LEDs and resistors

Engineering challenges

Gree remotes are not "press button, send byte". The remote keeps track of a full state and ships that state on every press, so I had to study the IR frames carefully and rebuild the same model in firmware. Fitting the ESP32, IR transmitter, receiver, regulator and a USB connector onto a compact board was the other half of the puzzle.

Solutions

I designed a dedicated PCB instead of stacking dev modules, tested the IR LED + receiver separately first so I knew the optical side was healthy, and styled the web UI to match a real remote layout instead of being a generic button grid.

Results & metrics

Working prototype with a fabricated and assembled board, a powered test setup at the desk, and a Gree-style web remote that anyone on the same Wi-Fi can open.

Future improvements

Next on the list: timer schedules, MQTT for Home Assistant, a small printed enclosure, and IR decoding to confirm the AC actually received what I sent.