2021/06/12/ir-remote-reveng/

[utterances-bot]

Reverse-engineering an AC IR remote protocol « Davide Depau's Blog

My personal blog

https://blog.depau.eu/2021/06/12/ir-remote-reveng/

[no1knows]

Thanks so much for your efforts here!

I stumbled across your post while trying to emulate the remote control for my workshop air cleaner: https://www.recordpower.co.uk/product/two-stage-air-filter-with-remote-3-speeds-and-time-delay (i.e. this remote: https://www.recordpower.co.uk/assets/products/product_images/prod_000592_feature_0_1335862096.jpg) on a Wemos D1 running Tasmota, that's connected to an Ikea air quality sensor (i.e. copying this: https://blakadder.com/vindriktning-tasmota/). I'm hoping to make the air cleaner smart, by having the Ikea air sensor control it over IR (and connect everything to Home Assistant over MQTT).

For posterity, I recorded the following IR signals from the original remote:

OFF BUTTON: {"IrReceived":{"Protocol":"KELON","Bits":48,"Data":"0xFF20B0046F90FF00","DataLSB":"0xFF040D20F609FF00","Repeat":0,"IRHVAC":{"Vendor":"KELON","Model":-1,"Mode":"Auto","Power":"On","Celsius":"On","Temp":24,"FanSpeed":"Auto","SwingV":"Auto","SwingH":"Off","Quiet":"Off","Turbo":"On","Econo":"Off","Light":"On","Filter":"Off","Clean":"Off","Beep":"On","Sleep":-1}}}
ON/SPEED BUTTON: {"IrReceived":{"Protocol":"KELON","Bits":48,"Data":"0xFF20B004CF30FF00","DataLSB":"0xFF040D20F30CFF00","Repeat":0,"IRHVAC":{"Vendor":"KELON","Model":-1,"Mode":"Auto","Power":"On","Celsius":"On","Temp":30,"FanSpeed":"Auto","SwingV":"Auto","SwingH":"Off","Quiet":"Off","Turbo":"On","Econo":"Off","Light":"On","Filter":"Off","Clean":"Off","Beep":"On","Sleep":-1}}}
TIME BUTTON: {"IrReceived":{"Protocol":"KELON","Bits":48,"Data":"0xFF20B0045FA0FF00","DataLSB":"0xFF040D20FA05FF00","Repeat":0,"IRHVAC":{"Vendor":"KELON","Model":-1,"Mode":"Auto","Power":"On","Celsius":"On","Temp":23,"FanSpeed":"Auto","SwingV":"Auto","SwingH":"Off","Quiet":"Off","Turbo":"On","Econo":"Off","Light":"On","Filter":"Off","Clean":"Off","Beep":"On","Sleep":-1}}}

When I send these same codes using the Tasmota IRSend command, they show up correctly on another Wemos D1 (i.e. the above codes are shown), but the actual AC400 unit doesn't respond to the signals. If you have any pointers, please let me know. Otherwise, I'll leave this here in case it helps anyone! Thanks again.

[depau]

Maybe check the signals with an oscilloscope and compare to the original remote.

[no1knows]

I'm very much out of my depth! :) ...but hooked up my DSO138, updated the firmware (https://github.com/ardyesp/DLO-138) to get a serial out to the PC and used miniscope (https://tomeko.net/projects/dso138/index.php?lang=en) to display. Outputs are here: https://drive.google.com/drive/folders/1UhnESRY_whARjL2_wJ0DXq3uPjibIguJ

They certainly look similar, but the frequency seems (~3x ?) lower on the remote vs. Tasmota given one scale is 0.1s and one is 10ms...

[depau]

@no1knows I think you need to better read the DSO instructions on calibration, improve your soldering skills, reflow it with decent solder and flux and properly wash it with an ultrasonic cleaner or something (or have someone else do it).

Those traces look awful, they should look like square waves, not like physicians handwriting.

[depau]

Hey @no1knows, I just stumbled upon this conversation and I'm a bit ashamed of how I responded, there was no need for me to be this harsh and I'm really sorry about that.

I hope you managed to reverse-engineer your remote, if you have any questions let me know :)