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How would I make a HVAC simulator to see what a thermostat would do if the indoor temp was 425°F (frozen pizza cooking temps) (reddthat.com)
submitted 5 days ago* (last edited 5 days ago) by batvin123@reddthat.com to c/askelectronics@discuss.tchncs.de
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I bought a nest gen 2 thermostat to play with a open source project that revives old nest thermostats (https://nolongerevil.com/). Since I don't want to install it into the home, because it will be a toy. I was thinking of building a test rig using a arduino or esp32 to simulate a HVAC and indoor temperature. I'm IT guy, not a HVAC guy, I think this would be a good learning project. Any suggestions?

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[–] dgriffith@aussie.zone 7 points 5 days ago* (last edited 5 days ago) (1 children)

If you're just simulating the temperature there's pretty much just three options:

  • The thermostat will simply command the HVAC system to maximum cooling, just like with any temperature well above the setpoint.
  • The thermostat will treat that value as a faulty sensor, report "error faulty sensor", and not do much in particular.
  • The thermostat will crash due to an overflow of some sort as its software was never tested with inputs like that.

Personally, I'd go with, "error faulty sensor" as the most likely outcome.

(Edit: you can stimulate the temperature by setting your house on fire. Better to just simulate it)

[–] batvin123@reddthat.com 1 points 5 days ago (2 children)

I do want to stimulating the temperature. Also interesting theory, it would be cool to put it to the test. But I need some way to simulate a thermistor. Also, The testing rig I want to build could be a cool demonstration piece for how a thermostat works. I might donate it to some tech school when I'm done with it. Time will tell

[–] rain_enjoyer@sopuli.xyz 1 points 5 days ago

thermistor is just a resistor that has resistance varying with temperature. often that relationship is linear over a reasonable range, like with Pt100, and you can probably get away with using potentiometer instead. that said you have to figure out what you have there, because there are many options