I have a hood over my stove that I would like to turn smart. The goal would be when we are cooking to turn it on if things get smokey. Too many times we will cook and then a smoke alarm will give a warning (nest) and it would be great to have the hood just start. The current fan setup has a knob under the hood and it has 4 settings: off, low, med, high. When I look at relays to put in there hood’s junction box, only on/off relays are available. I see there are wifi fan modules but that wouldn’t work well as it would bypass the hood’s actual switch/knob. Does anyone have ideas or examples of making the cooking hood fan smart?
I think you’ll have to use a multimeter and figure out what the knob is actually doing (and obviously only if you’re comfortable working with mains power).
I ‘smartified’ my range hood a number of years ago (and actually updated it to work with ESPHome a year or two ago). Maybe you can find some inspiration:
In my case, it has 3 push buttons that control the speed. I essentially replaced the buttons with relays and then read the state of the buttons; end result is I can control it with either the buttons or via HA.
Whoa, that’s fantastic. I’ll definitely read up on your project and is something I want to copy. Thanks for sharing. Well I’ll check I just thought the knob was a dumb dimmer for the exhaust fan but I’ll check to be sure, will be easy enough to find out.
So if I understand your project correctly, you have a relay with each speed control of the fan, the dumb controls can do this but so can your Particle Relay Shield that has a esphome device attached. I assume that in your program you can’t turn on for example “low” and “high” at the same time. Your espHome board turns on the relays remotely. And you have this attached to Home assistant or all working remotely?
It’s all integrated into HA, yes. When I originally set it up, all of the logic was on the microcontroller, but when I switched to ESPHome I decided to do all of the automated speed control in HA because I found it easier to setup and tweak.
Yes, although the way the fan was wired this wasn’t possible anyway.
I modified my range fan similarly. It has a five-position switch: off, low, medium, high, and max — each with its own wire terminal. With a multimeter I determined that each position closed a switch to the 110v hot. So I was able to replace the switch with a four-relay Tasmota board, and wire the original switch to GPIOs so it can still be used to control the fan. Tasmota has interlocks so only one relay closes at a time. The board also had a serial uart I could attach an air quality sensor, so I can use automations to detect when the fan needs to turn on. Separately I wired a dimmer module to the range’s lights to make them smart as well.
Similarly you could use normal 2-ch smart relay like Shelly 2PM skipping one of the speed levels. For example off-low-max. You can connect both low and med from the knob to same input pin of the smart relay.
programing an esphome device seems next level to me. I have to do all the multimeter checks when the wife isn’t home it could be a few weeks but these are great ideas