FROSTCALLER

1. 📺

   Your remote is a torch

   An air-con remote is just an infrared LED — a little torch your eyes cannot see — blinking a pattern of light. The AC watches for that pattern.

2. 🔦

   We build a second torch

   A cheap Wi-Fi chip with an infrared LED on it can blink the exact same pattern. The AC cannot tell the difference, and does not need to.

3. 🧙

   ESPHome writes the code

   ESPHome already knows the patterns for dozens of AC brands. You write about 12 lines of settings — no programming — and it builds the firmware for you.

4. 🏠

   Home Assistant gets a thermostat

   The box appears in Home Assistant as a normal thermostat card: mode, temperature, fan speed. From there, automate it however you like.

The one honest catch: infrared is one-way. The box shouts at the AC but never hears back, so Home Assistant shows what it believes it set, not what the unit is truly doing. Everything below is designed around that. Keep your original remote.

All six, side by side

The same information without the storytelling. Tap a name to open its steps.

Read the middle column first. “Fully local” means the device keeps working with the internet unplugged and no company can switch it off. “Cloud” means the maker can change the rules, add a subscription, or shut the servers down — which has happened to plenty of smart-home products. That is the whole argument for the DIY paths, and it is yours to weigh.

About the prices: they are typical AliExpress asking prices, seen mid-2026, before shipping and import VAT, and they move constantly. Sort by orders and reviews rather than by the lowest price, and prefer a seller with a local warehouse if you would rather not wait a month. Nothing here is sponsored.
About the other currencies: this page makes no network calls, so the exchange rates are fixed and rounded, not live. They are for a sense of scale — trust the euro figure and your own checkout page.

“Try it” is not a cop-out. Most budget units are made by a handful of factories and rebadged, so the name on the front tells you less than the shape of the remote. Start with the platform named, give it thirty seconds, and if the unit stays silent go and copy your own remote — that route has never failed anybody.

Everything else in the room

The same transmitter runs all of it. One well-placed blaster can drive every infrared thing you own — add a button per command and stop losing remotes.

Not sure? Go by the shape of the handset

The shape of the remote tells you more than the badge on the air conditioner, because the same handset is sold under a dozen brand names. Find the one that looks like yours and the guide will set the protocol for you.

Pick the closest match — it does not have to be exact. The colour and the button labels vary a lot; the outline is what carries the information.

🪶 The Scribe companion page Identify your chip in one click, watch the live log, catch the codes your remote is shouting and turn them into config. It speaks Flipper Zero too — use the dolphin as your receiver and it becomes the easiest capture rig in the house. No install Reads .ir files Exports ESPHome & SmartIR Chrome or Edge →

Which pin can I use?

Not every pin on these boards is free, and the ones that are not will let you find out the hard way — by refusing to boot. This is the map for the board you picked above.

This writes the file, not the firmware. You still press Install in ESPHome, and the first build takes a while. If ESPHome rejects a board name, the board list has simply moved on — try esp32dev, which works on almost anything with an ESP32 in it.

Six ways to get firmware onto the chip

This guide uses the first one throughout, because it is the kindest. The others all work too, and one of them may suit you better — especially if you would rather write code than configuration.