Measuring IBU using arduino

[SmileWithBeer]

The general method for analysis hop bitterness is to extract the beer samples into isooctane and measure the peak height at 275 nm. Now I would like to build an arduino-based analyser. However I do not know what components I have to order. Can somebody help me?

 

[AlexKay]

I’ve toyed with this idea. 275 nm leds are available, and I’d use a photoresistor. 3D-print something that keeps these in darkness and allows you to insert a cuvette. The real trick is going to be calibrating the detector linearity.

325 nm leds do not seem to be as common, which is a pity, because a hop storage index measurement would also be fun for homebrewers.

 

[MuddyBrown]

This is on my list of projects as well. I'm tempted to skip the isooctane and centrifuge steps, and just see what happens with using a pulsed LED array and suitable detector setup. Simplify things. Worst that happens, it does not work. Or poorly.

 

[SmileWithBeer]

I’ve toyed with this idea. 275 nm leds are available, and I’d use a photoresistor. 3D-print something that keeps these in darkness and allows you to insert a cuvette. The real trick is going to be calibrating the detector linearity.

325 nm leds do not seem to be as common, which is a pity, because a hop storage index measurement would also be fun for homebrewers.

The problem ist which led (since 275nm isn´t visible) and photoresistor really work and give finally enough signal. I tried several ones but unfortunately without succes.

 

[AlexKay]

The problem ist which led (since 275nm isn´t visible) and photoresistor really work and give finally enough signal. I tried several ones but unfortunately without succes.

Can you post which LED you used and how you hooked it up and to what? What I’m finding has pretty demanding input requirements: Vf ~ 6 V, If ~ 500 mA. That means if you’re using a 12 V supply, you’re looking at a series resistor that’s ~10 ohms and rated for > 5 W. Once it’s hooked up check the voltage across the diode to see that it really is ~ 6 V. 275 nm light is invisible but will make anything fluoresce at visible (blue-purple, typically) wavelengths. A scrap of white paper should allow you to see the output if it’s there at all.

 

[Climb]

For the electrical design of the analog front end (photodetector circuitry), do some searches on “pulse oximeters”. You can get some hardware ideas for the analog back end (LED drive circuitry) from these products as well.

For the development process, be sure to over design hardware performance while you figure out accuracy and noise related requirements.

Good luck.