this post was submitted on 18 Feb 2024
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ESP32

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Howdy, long time lurker!

I was wondering if anyone could give me a hand with trying to pull data from my Harmon Absolute43 pellet stove. Looking at the board, I see an RJ45 connector and thought "seems like a wireshark-like sniffer would do the job".

However, all searches end up looking at networking rather than simple data sniffing. Any ideas as to how to add a "bridge" that also stores the data? From there, I can do the publishing side of things, just the hardware component for me has me scratching my head.

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[–] [email protected] 2 points 7 months ago (1 children)

While I don't have advice; I've gotta wonder what kind of data you're expecting to get out of a stove...

What are you up to OP?

[–] [email protected] 3 points 7 months ago (2 children)

Lol well, it's got a relatively small hopper, which means it's really easy to miss refills. I know, getting into the habit is the "right" way, but if this thing has easy access to the "low fuel" indicator, I may as well utilize if possible.

Another thing is I'm trying to optimize the temps, and seeing a trendline is easier than it's "estimated" usage it's been giving me.

Also, it has a wireless temperature gauge that I may as well tie into my system I have setup.

And lastly, because why not πŸ™ƒ

[–] [email protected] 2 points 7 months ago

Ah, fair enough.

Honestly it seems like the easier route, instead of trying to intercept the control boards signals, would be a thermistor/thermocouple and a direct connection to the low fuel indicator (either the input sensor, or output led. Perhaps via a photodiode like the other guy mentioned).

[–] [email protected] 1 points 7 months ago (1 children)

Quick question the low fuel indicator is it some sort of coloured LED?

If so you could just use a small photo sensitive resistor over it and when that lights up send data to something like home assistant.

[–] [email protected] 1 points 7 months ago (1 children)

Nah, the screen itself is a capacitive touch one. Technically it "flashes" when getting low, but it's not really helpful.

I waffled on doing something like that, but once I found the RJ45 I swooned at the possibilities lol

[–] [email protected] 1 points 6 months ago (1 children)

I'll bet it isn't Ethernet. Do you have a scope?

[–] [email protected] 1 points 6 months ago (1 children)

I do not! Any suggested ones I could try to find?

My plan is to replicate the wire layout. So first, just use a random 5e and compare the wires. Best case they were lazy and it's just the same layout with different pin outs. Worst case I'm making a new cable with my large box of cat 6.

Wave and holler if that plan is naΓ―ve πŸ™‚

[–] [email protected] 2 points 6 months ago

I bet it is something simpler than Ethernet. I would open it up and look at the board. First I would look for magnetics because that would indicate Ethernet. I would look for labels on the silkscreen. I'll bet it is something simple.