After 23 years, the main control board on my spa (hot tub) seems to have died. Replacement cost: $800US. I’ve often wondered whether it would be possible to replace it with ESPHome.
Now I’m giving it more thought, and wondering if anyone has done anything like this before.
The key functions of this board are to drive 8 relays which run the pumps, heater, light and ozone generator. There are two temperature sensors and one flow sensor. It also drives the control panels in the spa itself.
I see they sell 8-channel ESP32 relay boards. $20 sure sounds better than $800. I’m not sure whether I’d have enough GPIO pins left for a couple of temperature sensors. I could probably live without the flow sensor. Or feed data from the ESP8266 I already have in there, monitoring temperatures independently of the spa controller.
I’d lose the use of the spa’s built-in control panels, since I don’t really know they communicate. From what I can tell, it’s some serial protocol, since I think it’s just two wires. But I’d gain the ability to run everything through HA. I could even set up the default web server in ESPHome and have some crude control that way. A waterproof display would be a nice future enhancement, but not totally necessary just to get it back up and running.
