I have just pushed a preliminary release to GitHub with support for PWM actuators. I am not sure it is a good idea, because I will be going on a 2 week holiday! So this release will come with bugs and without support.
Anything that is broken will be fixed when I get back.
You can read the details on GitHub:
I have been testing the PWM actuators with sous vide cooking. I have not tested this in a mashing setup, or in a fridge.
I have tested in Fridge Constant mode: one sensor, one actuator.
This means the beer PID is not used. The heater and cooler are driven by a simple PI controller.
You will have to tweak the PI gains yourself, there is no autotuning.
It might be possible to use this release in a HERMS, with the beer sensor in the mash and the fridge sensor in the HLT. The HLT temperature setting will then be automatically adjusted based on the mash sensor, similar to how the BrewPi fridge algorithm works. I recommend setting a max temperature of 70C in that case, so you will limit the HLT temperature to the temperature at which the enzymes denature. I have not had the time to actually test this in my HERMS. It might not work at all. I have just finished the code and have no time to test before I fly to Vietnam/Cambodia.
Now for something that I have tested a bit:
Sous vide cooking with BrewPi
My setup is very simple:
- A BrewPi Spark
- A OneWire Temperature Sensor
- A 40A SSR
- A cheap rice cooker (700W)
In the video, you can see BrewPi give the rice cooker very short pulses to keep the temperature steady.
Today, I had marinated pork tenderloin for diner. When cooked at 58 °C for 3 hours, it is pink all the way through and very tender. After cooking in the sous vide, you just have to sear it at high temperature in a skillet.
And this is the result:
And the temperatures:
If you have a rice cooker, I really recommend trying this some day. Super easy, and super tasty. You don’t need a vacuum sealer, you can just use zip lock bags and the ‘water displacement method’.