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  • Author Author: lawsonkeith
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Raspberry Pi Homebrew controller with Node Red UI

lawsonkeith

Introduction

For this project I'm going to upgrade my trusty home-brew temperature controller.

 

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I'm using a fish tank temperature controller at the moment to control a heater belt with a relay which is kind of ok apart from I need to go into the garage to check what it's doing and the temperature sensor which is just a cheap thermistor just gets bungee'd to the outside of the mash tub so I'm not sure how accurate it is, especially since the temperature sensor ends up being close to the heater.

 

Also the buttons seem to be getting harder to use on my mega cheap control unit so it's quite hard to change the set temperature at the moment when I'm going between standard and 'fancy' beers.

 

Upgrade

So I'm going to use my raspberry Pi to upgrade this to use Node Red so I can check what my beer is doing without leaving my arm chair.  I'm also going to use an industrial PT100 probe so I get a better temperature reading.  The first thing to do is a quick drawing of how this is going to be wired up, I'll use an Analog Hat (PiIO_ADIO) for the Pi to do all the interfacing so I just need to add a power supply and mains relay to my enclosure, since the interface PCB has a step down supply for the Pi I can just use a single 0.63A 24V PSU to power everything.  I'll mount everything on DIN rail then just use gands to seal the box (ignore irrigation references that's another project).

 

 

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So the next task is get the tools out and get this up and running.  First off with an enclosure it's worth checking everything is going to fit, here I've mounted the DIN rail and can now check the box is big enough.  You can see my relay,power supply, PT100 sensor and Pi with IO board.

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Glands can be marked with marker then cut out using a hole cutter, remember to bake sure there's enough room round the back for the securing nut.  The PT100 sensor was mounted in the fermentor lid using the same approach.

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So that get us to a point where we can now wire up the box to our schematic, this just involves mounting things on DIN rail and connecting the wires.

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  Here you see the control box and orange brew belt used for heating the beer,I usually put a jacket around this to improve efficiency when I'm brewing.  You can see also the PT100 sensor probe is much better located for sensing the beer temperature.

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Software

So now we can do the software, I plan to use node red to do the user interface but do the control from a python program.  I'll us a MQTT server called mosquitto to enable the 2 to talk via MQTT messages.  SO the user interface will be visible on any browser, the architecture looks like this:

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So I the flows for this in Node red end up just wiring MQTT message nodes to user interface components.

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And in the python program we use the low level drivers that come with our IO board and then talk to the UI using MQTT. For the temperature control we just average the PT100 sensor reading then apply a deadband to stop the heater continually turning on / off..

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So this gives us the following mobile phone view:

 

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And another view to control the process, which is just an enable and a setpoint.  The UI is visible on a mobile or and PC with a browser.  The cool thing is you don't need to pre install any software.

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You can see we can accurately control the beer temperature and use node reds charts to see what the controller is doing over time.  Perfect for bewing that specialty Lager!

 

Source code can be viewed here.

https://github.com/lawsonkeith/PiIO/blob/master/examples/hydro_ADIO.py

  • Very nice implementation of MQTT and Node-RED.  

     

    I was a bit curious if the "Rode Red" in the title was intentional or not though.

     

    Well done!

  • in reply to dubbie

    If you just want to use the kits it's pretty easy I think you just get 2 cans of malt extract and mix them with hot water and throw some dry yeast on the top.  I'd say you can get beer as as good as mid range cans?  It doesn't work too well for some styles like lager or highly hopped beers though.  You can buy a kit online for about 70 quid.  If the fermenter is going somewhere where the temperature is constant (say your living room in summer) you don't need the heater,

     

    If you want to progress to doing your own mashing (all grain brewing) then it's possible to mimic draft beers fairly easily.  Again some styles like lager are much harder but if you're just after an ale it's not too difficult.  You do need a lot more equipment for all grain brewing though. - but you are free to do your own recipes.

  • This looks fun. My wife and I tried wine making when we were younger (much younger) and frankly all you could say about it was that you could drink it if you tried hard. A friend also made some cider once and it was the most filthy disgusting liquid on the face of the earth. Strangely, after 'aging' for a year as he didn't have the heart to throw it away, it turned out really nice.

     

    Dubbie

  • in reply to DAB

    Hi

     

    I've put a code snippet up now, I've put it at +/- 0.5.  I'll see haw it goes when I brew my first beer maybe I can get this down a bit.  The cool thin is I can now see how the heater is used over time which before I had no idea about.

     

    Keith

  • Nice update.

     

    How closely are you monitoring the temperature. + or - one degree?

     

    DAB