fermenter controller

[bluc]

Been toying with the idea of an arduino fermenter controller. Wondering if anyone knows of a pressure mat that will connect to an arduino for weight measurements so it could possible be convertered into a gravity reading? No idea how to do it wondering if its possible and if it would be accurate?

[ShiFu]

I don't know how to go about doing what you ask for... an eFermenter? 
Wash hydrometers are so cheap I just drop one in the fermenter bucket when I set it up.
That way I can take a quick read without needing to sanitize the hydrometer before and after every reading.

It would take quite a bit of experimenting...  BUT if the hydrometer could be "caged" in the wash and its top was pushing against a pressure sensor...?? 

[bluc]

Yes an e fermenter  I saw that mentioned before and I think that approach would also work. But my original idea was to work out the gravity by  the weight of the fermenter. It get lighter as the sugar is turned to alcohol but there are lots of variables, especially with fermenting on the grain. I think the caged hydrometer would be a better idea.
Would be cool to be able to get gravity readings without opening the fermenter, and have them automatically logged along with temps..

[moonman]

There is a expensive option which is prebuilt at www.beerbug.com. Never used one myself, but people on brewtalk say they work well.

[bluc]

Yea I saw that one, thats what got me thinking maybe there is a way to set one up using an arduino, especially after seeing the digital parrot..

[Eucyblues]

Beerbug is no more..

Given the density variables involved with different washes, I think I'll stick to the KISS principle

[moonman]

there still alive and for sale i just got the web address wrong www.thebeerbug.com

[ShiFu]

So cool! Only $200.
I want one 

[ShiFu]

But after reading through some posts on their community forum it seems the BeerBug is indeed buggy. 
Lots and lots of complaints about the units not working correctly, or working at all, and to access your data you need to pay them a monthly fee?! 

I'd say give them another year to get things sorted before revisiting the idea of buying a BeerBug. 
 

[Eucyblues]

Sounds like a cleverly packaged micro load cell strain gauge device - fishing line attached to known mass suspended in the wash - the line connected to the load cell - changes in the density of the wash cause the 'torpedo' to tend to rise or sink affecting the load on the strain gauge

All very tricky to get right I imagine

A 100g load cell can apparently measure to +/-50mg - for about $10. See attachment

Could make a good experiment for an e-Parrot alternative ...God smack me down for such a thought!!!

On second thoughts - I can't afford to take the P*** out of the Almighty
 

[Edwin Croissant]

I have one of those sensors and a HX711 interface module and tested it out on an Arduino. It works    The HX711 module can be bought for less then one euro on AliExpress. I think that the cheapest way to get a 100 gram weighing sensor is to buy one of those 100 gram pocket scales. These can be bought for less then 4 euro’s. Use a small rc servo or a solenoid to lift the torpedo for zeroing and Bob is your uncle At first thought calibration is simple, in air the readout is 0, in water the readout is 1.000. The get 50 gram buoyancy in water the torpedo must be 3 cm in diameter and about 7 cm long.   

[bluc]

Would the arduino be able to use the sensor from a pocket scale?

[Edwin Croissant]

I found a movie on YouTube that shows a similar sensor in one of those pocket scales. So connect the sensor to the HX711 board  and that board to the Arduino and you can measure weights. The bare sensor I bought a while ago arrived malfunctioning, I got my money back but was able to repair it as the problem was a bad solder joint. Maybe the bare sensors they sell on AliExpress are the rejected sensors from the scale manufacturer.

[Eucyblues]

At first thought calibration is simple, in air the readout is 0, in water the readout is 1.000. The get 50 gram buoyancy in water the torpedo must be 3 cm in diameter and about 7 cm long.   

Thinking about this I can't see a real need to do a two point calib for brewing as the SG values run from say 0.98 to 1.07, so even if the '0' end was 10 percent out, the error at the measurement end will only be 10% of .07 max = 0.007 sg

[bluc]

Awesome info Edward will have a play when my arduino's arrive 

[bluc]

Found this on the web may be worth looking into my stuff for the parrot has slowly started to arrive so will be getting that out of the way first.. Also see in wiifm aeroponics thread he found a ph sensor that may come in handy to

Re: Density/Specific Gravity sensing
#6
Jul 02, 2007, 03:49 pm
you could try using a capacitance sensor to measure the density of the wort.  i've used a qprox qt300 capacitance-to-digital sensor with arduino for a completely different purpose, but humidity and density sensing is apparently what they are designed for - they're used quite widely in manufacturing industry...  and it's pretty easy to get the qt300 to talk to arduino.  it returns arbitrary 16-bit readings, so you will have to calibrate it initially by using the usual hydrometer (sp?) method, but provided you feed it a nice smooth power supply (pref batteries) the readings stay pretty rock solid.

actually, even if you don't calibrate your SG readings against the sensor, you could just get arduino to log the sensor readings every few hours or so and let you know when they become stable at the end of fermentation.  if you really want to know your alcohol content you could just do the initial and final SG readings manually.

i live in melbourne, australia, and ordered a few qprox chips from farnell in sydney (only cost about A$9 or US$7 each i think). outside oz i think they are widely available - spark fun should have them.

here's a datasheet for the qt300:
http://www.qprox.com/downloads/datasheets/qt300_102.pdf

if you do decide to use a capacitance sensor, i'd be interested to hear how you go.

happy brewing!
jon.