Tuned For Maximum Smoke

So we used to say, back in the day, before starting up a new piece of electronic/electrical gear. If we actually did get smoke, we’d say, ‘Aww, you went and let the smoke out!’ which was an extension of the tongue-in-cheek theory that all electronics are powered by the smoke inside the components.

Today, we’re wiring up the panel, uploading the code, and giving ‘er the old smoke test, so it’s probably as good a time as any to talk about how the various parts work together.

At the heart of it all, we’re using peristaltic pumps driven by stepper motors to evenly dose treatment into the brewing liquor over the duration of mashing in and sparging. Peristaltic pumps are in the class of pump known as positive displacement, meaning they move a fixed amount of fluid for every revolution. The stepper motors that turn them are also designed such that the exact number of revolutions can be controlled down to a tiny fraction. (That’s actually a lot more precision than we need.) Taken together, they make a perfect way to deliver controlled amounts of liquid into the liquor stream. Each salt will be mixed into a stock solution, 0.1g/ml, that the pumps will draw from small reservoirs. The acid can be pumped as-is, with appropriate tubing fitted. The only other piece of the dosing puzzle will be the section of brewhouse pipe where the treatments are injected, which is a problem for another day.

So here’s how we use these- we program the amount in grams or ml of each salt or acid called for in the brew log, plus the amount of liquor specified. Audrey will break up those total amounts into 9 equal doses, and add them as each tenth of the total liquor volume is reached. The brewhouse flowmeter provides an output of pulses that track with the flow, which Audrey will use to keep track of progress. One other handy function is the “warning track” alarm, which sounds when 90% liquor volume is reached. (This shouldn’t be necessary in a perfect world, but in our world the breweries are full of shiny things and squirrels, and the brewers are all 12 year old boys.)(Even the girls.)

Another handy thing for me is that there are stepper motor controllers that handle all of the fancy power switching on each motor’s multiple windings, according to pulses I send them from the Arduino controller on one wire. (That’s the four things across the bottom of the panel.) They can usually be had for less than 10 bucks apiece, well worth it. For test purposes, I just cheated in a line cord and an inexpensive flow meter. (The flowmeter could have been literally anything that generates a pulse, but it was handy and made me feel like this was a. real. test.)

The blue button steps through the items, yellow increments the values, and green starts the dosing sequence. (Told you it was just like a VCR!) Hit the green start button, turn on the water, and Audrey (hopefully,) takes it from there. So, how’d we do? I’ll save that for the next post….