I’ve recently made some updates to my home and have a puzzle to solve.
I have 2 bathrooms and a kitchen that share a vent stack. There is an inline fan located below the roof
and each branch has a damper. The inline fan is an Infinity AC fan controlled by ESPhome. The fan works well and the bathrooms have been easy to both automate and create manual controls.
For the bathrooms I have low voltage switches connected to an ESP32 that when toggled opens a particular damper. The opened damper triggers another automation that powers up the inline fan to about 40%. This has been working great, but now I need to add some control to the kitchen vent hood.
What I’d like to do is use the touch screen of the vent hood to send signals to my inline fan and dampers, bypassing the hood’s builtin fan. I’m hoping there is a way to intercept the pwm single from the hood and use it to send commands to the inline fan. There are 6 speeds on the touch screen.
Does anyone have an idea on where to begin with the project? I was thinking of first trying to figure out what PWM signals are being sent by the controller, but I have pretty limited tools. I don’t have an oscilloscope. Only a basic DMM. Most of my searching leads to creating a PWM from ESPhome, but not intercepting/interpreting one. To get the Infinity running I needed to create a pwm, but now I can just control it from HA. I’m hoping there is a way to read that the hood wants level 1-6 and I can automate accordingly.
Thanks in advance.
Edit: i realize that the controller might not be using PWM. I’m not sure. Attaching the wiring diagram.
Not sure if you’ve seen this but it may give you some ideas/leads.
This cheap logic analyser was recommended to me a while back and it’s worked well so far. I haven’t used it for PWM though. It can be used with Sigrok.
AU $7.78 14%OFF | USB Logic Analyzer 24MHz 8 Channel 24M/seconds Logic Analyzer Debugger For ARM FPGA Logic Analyzer Logic 24M 8CH https://a.aliexpress.com/_mOuGQtq
Update. I’ve finally gotten around to this project again I realize I’m in over my head.
I’ve use the logic analyzer and I get what appears to be a pattern of a long pulse, followed by a medium pulse, followed by 24 short pulses that repeats. The durations don’t change so I’m assuming it’s not a PWM but some other proprietary data signal. I’ve been unable to really see the difference in any of the states, but I can clearly see the pattern itself. I’m not sure what I should do to try and decode this signal. If anyone has advice it would be greatly appreciated.
I am a decoding newbie. But I would check the voltage on the signal wire(s) and then try to understand if it is using a common protocol. (Edit: 12V I guess from a re-read).
You can inspect the waveform and timings a little and start researching which protocols may roughly match what you see.
Edit: If it’s 12V then careful with below.
For example, I would start with Uart (both sigrok etc and ESPHOME can decode that). But I dunno if that kind of device typically uses uart. I suspect not.
Then I would actually try remote_reciever:. Maybe you get like a pronto or raw code.
I would also post on Discord as a lot of advanced users hang out there. They may have more informed guesses about what protocol similar devices typically use.
Some difference there has to be, that’s the only thing you actually need. Decoding that signal doesn’t really offer you anything if I understood your project correctly.
