Reverse Engineering And Networking The A/C Remote Control

IoT has become such an polarizing, overused term. But here it is in its essence: [zeroflow] had a thing (his airconditioner) and he needed to put it on the Internet.

For his contribution to this modern vernacular atrocity, he first had to build an IR debugging tool and reverse engineer the signals coming from the air conditioner’s remote. He wrote up a really good summary of the process, and worth reading. He loads up an IR library onto an Arduino and dumps the resulting 32 bits of information to his computer. In a process much like filling in the blanks on a word puzzle, he eventually determines which blocks of the data correspond to the remote’s different buttons.

Next he throws an array of IR LEDS and an ESP8266 onto a bit of protoboard. After writing some code, available on GitHub, he could set the temperature of his room from anywhere on the planet. We take it on faith that [zeroflow] has a compelling reason for doing so.

Bolstered by this success, he didn’t stop there. [Zeroflow] admits to having more than one thing on the Internet. Boom! Internet of things.

19 thoughts on “Reverse Engineering And Networking The A/C Remote Control

  1. I can control my air conditioning, but except for three motor-controlled clerestory windows in my kitchen (that I haven’t yet put on the internet, but could do easily with an IR on a microcontroller), I’d be cooling my neighborhood. My last trip of several days, it got rather hot on the last day, but I didn’t want to turn on the AC while I was on the road unless I had a robot who could find open windows and shut them.

    That’s a killer app.

  2. For the days when LIRC serial port receivers were still common and easy enough that the entire reverse-engineering stage would have just been a matter of asking LIRC to determine the protocol for you… oh well.

  3. I know we all like to DIY, but you can buy some very nice network enabled IR emitters units from Global cache and their prices are quite reasonable. Check out iTach IP2IR for wired ethernet and WF2IR for wireless, one unit can handle three seperately addressed emitters so you can potentially have a central unit serving three devices.

    I use mine for split system aircons and I had to do a fair bit of work reconstructing the aircon protocol, but once I had it developed in a script it was fairly easy to send the commands via the iTach.

    1. zeroflow here, for an commercial/industrial setting, IP2IR or WF2IR are simply the better solution.

      An IP2IR would cost me about 120€. Even if factoring in about 4h worth of work, the ESP + random parts is much cheaper and much more fun to build.

    2. While the IP2IR is a good product for commercial/industrial settings, it was simply not worth it for my use.

      An IP2IR would cost me about 120€ while all parts for the ESP have already been collecting dust on my workbench – and even with time billed it would still be cheaper in the end – and more exciting building it myself

    1. The rule isn’t to use “an” before a vowel, it’s to use it before a vowel *sound.* That’s why you say “a historic occasion” in the US, and “an historic” in the UK.

      It’s still wrong, I’m just being helpful. :V

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