Inline ethanol % meter

[manu de hanoi]

10 Mass spectrometry: a pocket sized mass spectrometer could be connected to the parrot, a particle accelerator would work as well.
Enough brainstorming,
Anyone tried anything in real life ?

[seravitae]

mass spec is great, but in our labs we've found that using mass spec isnt ideal way to quantify something, only to identify it. too much variability in the sensitivity of charged species - using GC with thermal detectors or spectrometers are pretty accurate.

[snuffy]

And one more: measure the pressure in the column with a micromanometer. Vapor density varies with %abv. It also varies with temperature (which covaries with %abv), so the conversion from pressure to %abv would be nonlinear. But that's not much of a difficulty - all of the methods require temperature correction.

After much thought about the difficulties constructing various sensors, I like (in order of complexity):

1) Hot wire mass/specific heat sensors. Model airplane glowplugs are nicely standardized platinum filaments and a Wheatstone or Rayleigh bridge is simple and straightforward. One drawback is glowplugs are low resistance/high amperage and operate at 1.5V or less. This makes the resistance of connections a potential problem.

2) An optically sensed micromanometer. This might be too fussy and would require frequent recalibration. On the other hand, it is probably the easiest to build for proof of concept. The Amateur Scientist has two nice designs that suggest other possibilities.

3) A float held down by an electromagnet and kept in a constant position by sensor (either phototransistor or sensing coils). The current in the electromagnet is proportional to the force needed to balance the buoyancy.

[guerrila distilla]

check this out:-

http://books.google.co.uk/books?id=7gsQ ... #PPA191,M1" onclick="window.open(this.href);return false;" rel="nofollow

it goes fairly complex on the subject, way too complex for me anyway

here's another one on using piezoresistive microcantilevers to measure ethanol:-

http://www.fresnel.fr/perso/lereu/RSI77.pdf" onclick="window.open(this.href);return false;" rel="nofollow

and another:-

http://www.seacoastscience.com/Download ... 0press.pdf" onclick="window.open(this.href);return false;" rel="nofollow

also, has anybody thought about monitoring the alcohol level at the top of the column in vapour form instead of in liquid form. that's allready being done by police officers all over the world - the breathalyser.

[schnell]

My money is on Ion Mobility spectroscopy...

[brewmaker1]

K.I.S.S. method.
Mount rheostat on side of parrot and attach an arm to alcoholmeter. Measure rheostat resistance as alcoholmeter raises and lowers. It should be pretty simple to write a program to convert the numbers

[trial&error]

what about an octane sensor out of a BMW? all the 135 & 335 (N54 motors) have them for adjusting the timing. (high octane = more timing, lower octanes = less timing; so motors dont blow up)