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[on:]

Hi again guys,
this time, not a problem yet, just a proof of concept or guidance is all that is required.

I like to make my own alcohol, but the process is often time consuming and tedious. I want to automate it and im sure the arduino is more than capable. its the parts that ill need guidance on. and later on, probably the coding. but for now just the parts.

first off, the one thing i dont even know if it exists - a digital alcometer. i need is to be able to read from 20 - 100%ABV.
if not, can i make one? here is the analog version (i have) - http://www.smugglers.net.au/index.php?p=1_42
the other things ill need are -

• 2x digital thermometers - no problem, i have these =analogRead
• 240VAC on off switch controlled by arduino - i expect this is ok too. =digitalWrite
• something to measure volume in mL =analogRead
• a tap - variable by the arduino. able to hook up to either gravity or mains fed water and control flow rate from off to 500mL per minute =analogWrite
• a tap - switching between 2 or 3 outputs from one input, low to no pressure on this one. =analogWrite?

what do you recon, doable?

[Reply #1 on:]

I would suggest doing some research on PID algorithms (http://en.wikipedia.org/wiki/PID_controller), since you will likely need something like that to control the temperature/feedback.

Of course, I'm not sure how much automation you will be able to achieve, given that the still will require, yeast and a food source to be added, beyond water.

[Reply #2 on:]

I think the water is for cooling, not for the product...

[Reply #3 on:]

I think the water is for cooling, not for the product...

If for cooling, you really don't need an automated valve...

[Reply #4 on:]

I would suggest doing some research on PID algorithms (http://en.wikipedia.org/wiki/PID_controller), since you will likely need something like that to control the temperature/feedback.

Of course, I'm not sure how much automation you will be able to achieve, given that the still will require, yeast and a food source to be added, beyond water.

will do some reading up like you suggest.
Im not interested in automating the brewing process, thats easy and takes care of itself mostly. Its the distillation process that i want to automate. So that is after the brewing has been done. its basically pouring "beer" into a 25L kettle and boiling it, trapping the steam and cooling the steam down.

I think the water is for cooling, not for the product...

Correct. the water is for cooling.

If for cooling, you really don't need an automated valve...

Well i think that its not entirely necessary, it would make things much much better. As it takes 2-3 hours to get up to temperature that doesnt need to be cooled and from 50-80 degrees jumps really fast, having it automatically come on would save me having to check it every 5 mins for 2 hours. Then, once it gets going the water needs to be adjusted as it get closer the the end of the run the temperature increases closer to 90 and more water is required.

The other tap is to switch the output of the alcohol. The first 500 or so mL contains nasties and needs to be cut off into a separate container. Also if it switches 3 ways, i could catch the tail end of the run in a separated jug too. Improving the quality furthermore. As for counting 500mL, i was thinking last night that i may not need a flow meter, just a simple switch that is operated when the liquid bridges two contacts set at the 500mL mark in a jar.

will need the alcometer to test the alcohol coming out and switch to the tails jug at about 70-80%ABV the 80-95%ABV will be the main "good stuff" used for drinking.

[Reply #5 on:]

There do exist digital hydrometers; so perhaps you can get one of those and hack it in some fashion (probably easier said than done?). There also exist gaseous alcohol sensors:

http://www.sparkfun.com/products/8880

I also found this thread:

http://www.homebrewtalk.com/f51/digitial-hydrometer-sensor-267405/

You might want to explore that forum, if you haven't already; there may be someone on there who -has- hacked an existing digital hydrometer...

Here's an actual sensor - and a description of how it works (maybe you could make something - perhaps hack up an analog sensor in some manner?):

http://www.gardco.com/pages/density/electric_hydrometer.cfm

[Reply #6 on:]

thanks cr0sh,

There also exist gaseous alcohol sensors:
http://www.sparkfun.com/products/8880

I Have one of these. Its ok for making LED light up by blowing on it while getting drunk, but its not really that sensitive or reliable and you cant really calibrate it that easily.
Its not gonna work for what i want. i want to be able to tell it to switch output containers when a % threshold is reached and turn off everything when a lower threshold is reached.

also found this thread:
http://www.homebrewtalk.com/f51/digitial-hydrometer-sensor-267405/

this has got me thinking. if i cant get a digital alcometer, is there a way to read and analog one digitally? i have a 2 types of range sensors already -
http://www.toysdownunder.com/infrared-proximity-sensor-1.html and http://www.toysdownunder.com/unltrasonic-sensor-lz2.html
maybe its possible to measure how close the glass tube is and make have a scale of distances to percentages?
i also was thinking maybe marking the float and reading it like you do with light and spinning wheels. But i cant alter the weight of it and texta will just dissolve into the high alcohol (Bad).
http://www.gardco.com/pages/density/electric_hydrometer.cfm
this would be great, but bloody hell its pricey!!

wanderson:
ive been reading up on PID, the page you given me and others. But im not sure why i need it? A thermister will just out a change in resistance that i could measure with analogRead, i can map that to a temp range and use in my program. would that not be correct?

[Reply #7 on:]

ive been reading up on PID, the page you given me and others. But im not sure why i need it? A thermister will just out a change in resistance that i could measure with analogRead, i can map that to a temp range and use in my program. would that not be correct?

You can use a PID, but it's more useful when you can vary the controlling object proportionally. Since I assume all you're doing is turning the heater for the distillate on or off, you can, if desired, substitute the simpler approach you propose just as well.

[Reply #8 on:]

ok, But ill be measuring the temp of the steam and varying the water flow.

The boiler will just an off switch once the alcohol % drops below a certain ABV. if i can get a alcometer that is....

should i still use PID?

[Reply #9 on:]

Since the flow from your tap varies, yes PID is eminently suitable. It can be tricky to tune the two PID parameters though. Your system may be simple/stable enough that you don't need anything more powerful than a simple feedback loop with a little hysteresis. Personally, I'd leave the PID out until your own control code starts getting too complex. OTOH, it might be a fun/useful learning experience.