Looking for some help that I hope some smart people out there can help me think through this or help with a simple app. I have the majority of my house on Hubitat but for my next project, I am working on creating an indoor electric brewery! Once I get this project finalized I plan to post a better writeup with pics and such but for now, without going into too much detail, I need a way to control the boil kettle. Because a vigorous boil and a slow simmer are the same temperatures I need a way to control how vigorous the boil is.
I am using @ogiewon 's Hubduino project (AMAZING Project!!). The boil kettle in Hubitat is just a standard switch, but "behind the scenes" the hardware is a D1 Mini Wemos board programmed so one of the pins is connected to an SSR that is wired to a 240V electric element inside my brew kettle. When the switch turns on, the D1 Mini sends a signal to the SSR to turn on the electric element, when the switch is off, it cuts off the signal and turns off the electrical element.
Here is what I am looking to accomplish with this:
- Have the SSR turn on/off every couple of seconds to control the vigor of the boil
- Turn the boil kettle element on and off from a dashboard
- Adjust the frequency of how often it turns on and off from a dashboard (thinking of this as a 1%-100% and then somehow adjust equate this to 1-10 seconds, 10 being Max and 1 being min)
- Have a safeguard in the system so the element doesn't turn on when there isn't liquid surrounding it. I have a virtual switch that we can use as a "predicate" switch unless anyone has another idea.
I hope that this makes sense if anything isn't clear just shout. Thanks for helping and if you are in Central PA, I am happy to share a beer with you!! 
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Hot sure what your kettle looks like, but perhaps the kettle outside surface near the top is a lower temperature that might change between vigor and simmer. Just a thought.
- Noise is probably not accurate enough.
- Might a beam of some sort reflect when simmering and not when boiling?
- A Piezo disk bonded to he outside of the kettle near the heat source might pickup the boiling bubble "noise"
IIRC, there is a HubDuino/ST_Anything device that supports Pulse Width Modulation, which may be a decent way of controlling the SSR. Take a look at the EX_Switch_Dim device in the ST_Anything library folder. Basically, it implements a dimmable light bulb, and allows for two outputs, one a simple on/off switch, and the other a PWM output.
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Awesome! Let me give that a try and I'll let you know how it works out. Again the Hubduino is a tremendous project, thanks for the hard work put into it and for sharing it out there! Be in touch soon.
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@ogiewon, I implemented the changes to the Arduino board and Hubitat last night. I ended up using the Ex_PWM_Dim device and used the PWM example sketch to help me put in the right values in my board sketch. So this afternoon I filled up my boil kettle with about 5 gallons and it works absolutely perfect!!!! I am beyond excited, happy, and this was super easy to implement. THANK YOU for pointing me in this direction. Thank you also for the massive amount of effort you put into this project and also staying active in this community, very much appreciated!!
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That is awesome to hear! So glad the PWM signal did the trick!
I can tell you that after having a brewing setup for years under ST and now HE the reliablility factor is most important.
I had thermocouples controlling heater outlets for fermenters/wash with WebCore pistons and the number of failures, one is too many, got to me. Lots of thermal runaways with devices not reporting properly or timely.
I just bought a dedicated InkBird Heat/Cool controller for the 2 fermenters and built this controller for the boiler.
Solid products and about 150.00 CDN in parts.
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Nice setup! I did also run across that type of setup when I was thinking about my build but decided I wanted to go the Hubitat route rather than stand-alone PID devices. So far I brewed once on this and I was really happy so far with exception of the boil control, so needless to say after implementing this PWM solution above I am excited to brew again to try it all out! The way Dan developed the Hubduino platform that I like is most of the logic is handled locally on the Arduino rather than relying on your wifi and the hub to control the logic, it makes a huge difference. We'll see how a couple more batches go (just means I need to drink more beer!!).
As far as fermentation I can understand that side and I built a similar setup to help control fermentation temp. Always fun projects to tackle for HomeBrewing!!
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