Flow sensor for electric brewery
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Flow sensor for electric brewery

by CapnBry on Sun Mar 10, 2013 8:50 am

I have a problem. When I look at my brewery I think that if it is working, then it doesn't have enough features. Certain parts of the brewing process suggest specific liquid flow rates, but without instantaneous feedback, how can anyone ever really judge if they're doing it right? It seemed that commercial flow meters are complete garbage or are insanely expensive. Luckily, Adafruit had my back with an inexpensive flow sensor.

I slapped a couple quick disconnects on it, and replaced the screws that held it together with 3/4" #4 brass wood screws to allow it to be mounted to a nice enclosure.
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The rest of the parts were maybe $15-20, but I had them sitting around from my other projects. I need to get a 9V battery clip. Soldering wires onto a 9V battery because you're more excited about getting it working than driving to Radio Shack is surprisingly difficult.
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The PCB is custom made from OSH Park and drives the LCD, PWM backlight and contrast, and of course counts the sensor pulses. I went a slightly different way than the example sketch does it, because I found that the resolution at low flow rates was too coarse. I use Timer1 set to 62.5Khz and use the input capture interrupt to store the elapsed ticks between pulses.

The sensor works great, but is quite a bit off spec (450 pulses per liter) at flow rates less than 4 lpm. I calibrated by running hundreds of liters of water through it and creating some calibration points that I can LERP between. Flow rate accuracy now pretty tight, off by a couple percent. Careful calibration can take this sensor down below its minimum spec'ed flow rate, down to about 0.7 lpm, but the pulses-per-liter count at that rate changes dramatically.

Here's some pictures of the device in action on the brewery, where it just snaps on to the existing pump infrastructure. Using sleep modes between pulses means the current draw is relatively low and the 9V battery should last roughly 30 hours in use.
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I still need to come up with some way of covering the front panel to keep errant beer out. I was thinking of a sheet of transparency cut to size and glued on with some spray adhesive but it sounds messy. Anyone have any ideas?
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Re: Flow sensor for electric brewery

by adafruit_support_bill on Sun Mar 10, 2013 12:47 pm

Wow! Very nice work! :D
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Re: Flow sensor for electric brewery

by beercannon on Mon Mar 11, 2013 10:17 pm

What phase of the process is this, a secondary fermentation?
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Re: Flow sensor for electric brewery

by jpbot on Tue Mar 12, 2013 1:57 am

For keeping beer out of the electronics, why not a case with a clear cover? Vetco sells some, though big enough for a 4x20 LCD would get spendy. Maybe instead, clear acrylic sealed inside case and mount the lcd behind, recessed a bit which might make it harder to see, but should keep it mostly dry, and anything that runs in should stay mostly off the delicate parts.
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Re: Flow sensor for electric brewery

by adafruit_support_bill on Tue Mar 12, 2013 6:02 am

Here is another waterproofing option. Although you have done such a nice job of packaging already...
https://www.adafruit.com/products/905
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Re: Flow sensor for electric brewery

by CapnBry on Tue Mar 12, 2013 8:13 am

This is the brewing process. The kettle in the middle is the mash which is recirculated through a heat exchanger on the left to control mast temperature. Then that's pumped to the right kettle for boiling. The original plan was to use the flow meter to measure the amount of liquid going into the boil but it also works for preventing the re-circulation from sticking due to creating too much pressure on the false bottom.

I've see people put their projects in watertight or resistant boxes with clear lids, but I find those to not be very attractive. I was hoping someone had an idea on how to create a spill-resistant membrane in this age of having access to all sorts of high tech printers and materials.

On the topic of the flow sensor itself, I will say that it is important to orient the sensor in the position it will be used in before calibration. I calibrated my sensor horizontally and flat but found it was easier to read if rotated around the axis of fluid flow by about 40 degrees. This created roughly 9.3% error across the board that required a complete recalibration.
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Re: Flow sensor for electric brewery

by beercannon on Tue Mar 12, 2013 9:53 am

Nice setup. I've made a few beers here and there with malt extracts and pelletized hops, but never got into the more serious processes like sparging, etc. Great to see homebrewed technology used to make beer!
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Re: Flow sensor for electric brewery

by scottinnh on Wed Mar 13, 2013 3:16 pm

Yes, very nice setup.

I'm probably not the first homebrewer to say this, but homebrewing literally WAS what caused my introduction to DIY and electronics. Crafting a base for your the grain mill, and making a power switch to control temperatures in a fermentation chamber. Things I could have bought, but which many bloggers have documented and I could easily follow.

At it's simplest homebrewing is like making a 3 hour batch of tea - not complicated.

But if you want a reason or a goal to learn DIY, I can think of no better reason than brewing, as the process constantly presents opportunity for you to refine your steps and equipment.
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Re: Flow sensor for electric brewery

by scottinnh on Wed Mar 13, 2013 3:18 pm

Is your setup based on Kal Wallner's panel (of theelectricbrewery.com fame)?

I'm looking to eventually go 240v as I have an outlet just inside my garage (conveniently near the exterior garage door, so I can go mobile like you have and not need the oven hood).

BTW Yours is the first mobile one I've seen. I did a double-take looking for the gas burners.


PS - for the readers... if you think electric brewing is out of reach because you're stuck on 120v, see jkarp's awesome countertop setup: http://byo.com/component/k2/item/1933-c ... ing-system
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Re: Flow sensor for electric brewery

by 3d0g on Fri Mar 15, 2013 11:49 am

scottinnh wrote:if you think electric brewing is out of reach because you're stuck on 120v, see jkarp's awesome countertop setup: http://byo.com/component/k2/item/1933-c ... ing-system


Aww, shucks. Thanks scottinnh.

I recently did a video of a brewday using my countertop brewing system - http://www.youtube.com/watch?v=lc5EEy3PCtQ. I still brew with it a couple times a month.

Cheers!

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Re: Flow sensor for electric brewery

by stainlessbrewer on Sun Mar 31, 2013 3:58 pm

I have been wanting one of these for my little home brewery but I'm a total idiot when it comes to this stuff. If you want to build another I'd be happy to pay :D
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Re: Flow sensor for electric brewery

by northseaMN on Wed Sep 25, 2013 8:48 pm

I really like this flow meter and want to build one similar for my brew station. Can anyone help me identify which board and LCD I should buy to go with the flow meter? I don't know much about electronics so specific part numbers would be nice!
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