Brewery controller & stir plate

[Stu H]

Over the summer I took advantage of my workplace's extensive tool collection and put together couple of gadgets for the brewery, a brewery controller, and a magnetic stir plate.

The brewery controller is basically just a Sestos PID controller and a solid state relay for the HLT, and a switch for my pump. I put it all in a big box so when I want to add something extra there's space.

I got the panel mount sockets from Jaycar, and the IEC socket was lying around work. i decided to go for a 2.5mm audio socket for the sensor input. I only have two of the power sockets wired up currently, with one spare.

The guts inside. Note the grounding post - very important!

For the stir plate I basically glued some rare earth magnets to a 12V computer fan, and experimented with different ways to vary the speed of the fan. I tried a few different circuits to vary the amount of energy being delivered to the fan: Potentiometer, PWM generator, and a voltage regulator. The voltage regulator method totally works the best, and is relatively simple to implement.

I would put up a picture of it stirring water, but both my stir bars were tipped into my fermentors, along with the yeast staters!

One thing I noticed was that it was much easier to get the small stir-bars to catch and spin rather than the larger ones, so I set the magnets really close together.

I put the circuit together with stripboard. It's based on an LM317 voltage regular IC, and I found it here: http://seanterrill.com/2010/04/26/build-a-better-stirplate/

To raise the fan I found some random bits of scrap prototyping plastic and tapped threads in them. I then screwed the fan onto the improvised posts and epoxied them down to the box.

[mattd2]

Looks good Stu, those covered outlets look way easier and better than the standard ones I got a couple of years ago from Jaycar!

Have you tried the controller out yet? I have had one issue with my Sestos PID that it will not adjust the control time to less that 8 seconds (and if you try set it to 0, 1 or 2 it will change the timing to 70s!). Any problems with yours?

[Stu H]

Hey Matt,

I haven't gotten around to buying a new (weldless) sensor for my new HLT yet, so I've just been crudely taping an old sensor to the side of my old HLT and have just using the controller in on/off mode... Will let ya know once I pull my finger out!

[mattd2]

Sweet as, what are you looking at for the new sensor. I picked up a 1/2" BSP thermocouple with a 50mm probe off of ebay for not too much (I thiink <$20 landed). But if I were to by another one I probably would go for a PT100 so that I culd unplug it easily.

[Stu H]

Yeah bro, I'll totally be going for an Auber Pt100