I ran through 3-4 tanks of CO2 in 2021 because of a slow leak in my keezer. While that is resolved, it occured to me that the CO2 doesn't need to be on all the time. Not only does it waste money if there is a leak, it is inconvenient and there is some environmental impact. So for the past 6 months I've defaulted to shutting off when not in use. Since we have friends over every Wednesday (for FreeWill Wednesday) I have an alarm on my phone each Wed. reminding me to shut off the CO2.
But hey, I live in a smart home and I can solve this problem.
I started thinking about this a month ago and went looking for parts. First I found this zigbeen module that controls a relay. Then I found this water valve that is controlled by a 24v solenoid. Since the valve has John Guest push-in fittings, I knew it would fit right into my system.
The idea is pretty simple. The zigbee module is attached to power and the relay switches the 24v on to open the normally closed valve. The valve is inserted in the CO2 path after main the regulator but before the kegs (which in my keezer have their own individual regulators. Fortunately, this zigbee module can convert 24v down to 5v to run the zigbee part, so I only needed on power source.
Once put together, I can join the zigbee module to my Home Assistant install (or Smartthing, Alexa, etc.) and build some automations that control the valve and CO2