This is a work in progress but I’ve made some real advancements recently, so I thought I’d share.
I’m usually the hottest person in my house, so I tend to turn the heating off before bed. I’m often instructed, by the wife or kids, to go back down downstairs and turn it on, so I wanted a way to do this from upstairs.
My daughter’s bedroom is above the garage and I wanted to be able to check and control the temperature in the house based on her bedroom - the living room temperature varies loads because of the adjacent kitchen and front door.
- I found some projects where people were hacking in to their central heating programmers. I soldered onto the controller board so that I could use a raspberry pi zero to short out the ‘Advance’ button, which simulates it being pressed, so I can turn the heating or hot water on and off. I also used some GPIOs as inputs to detect if the LEDs were on.
Here’s the Pi zero with a voltage regulator:-
and here’s the finished controller.
- I’ve made up some temperature sensors using ESP-01, a voltage regulator and a USB lead (I’d go for ESP-12 if I needed more because they’ve got the regulator built in)
I flashed the ESPs with ESP Easy and they’re talking to Home Assistant over MQTT.
Here’s a screen shot of the Central Heating tab in Hass:-
Sensor Select lets me choose which of the sensors to use for controlling the heating. The Max and Min sets the threshold and there’s some automation behind that that checks if the heating is already on/off, so it doesn’t accidentally come on when it’s meant to go off.
I’ve also setup a Google Calendar, which I’m using to program a daily schedule. I haven’t fully integrated this yet since it’s too warm to have the heating come on at set times just yet. Best to get it sorted before the winter though!!
I can’t afford to buy loads of eTRV’s so I’m investigating a cheap way to make a plunger that I can fit on top of my existing TRVs. The end goal is to be able to control the radiators independently, so I can adjust things based on whether we’re upstairs, downstairs or if I want to be able to just warm my daughter’s room a bit and not have the rest of the house boiling hot!
If anyone has stumbled upon info to make your own eTRV I’d be interested to know. I’ve seen hacks to add WiFi to the basic one’s but their still pretty expensive.