DIY turbidity meters

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Revision as of 12:17, 18 September 2013 by Dusjagr (talk | contribs) (Turbi-2-Audio-SmartPhone interface)
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coming soon, first experiments by Andy and dusjagr looked great... see more details on DIY spectroscopy

BabyTurbiduino aka Daphna-2-MIDI Converter


OD uino breadboarding.jpg

Overview OD uino stackes.JPG

OD uino prototype.JPG


Kafi-Schnapps Detektor

Daphnia 2 midi.jpg

See more info and file on Thingyverse

Files for Ardunio and pd File:Turby

Kafi schnapps detektor calibrations sm.jpg

Daphnia-2-MIDI device

Baby2 turbidity.jpg

Some bugs in the cuvette:

Daphnia 2 midi pd.png

Testing different yeast culture densities:

OD meter yeast density.png

Turbi-2-Audio-SmartPhone interface

Tests with Bengt et al

It woooorks!

we finally soldered a mini-jack plug to go directly into the line-in.... muuuuuch better quality than through the air :-) who would expect that!

Baby talks modemStaayle.jpg

We made various tests the other night, trying to have the Baby communicating like a modem, bliip bliip bluup, first using a small piezo-speaker or the hi-fi in the living room. it's looking good:

FSK baby analysis.png

the free software Sigmira is kinda useful to test

Bengt had to modify the SoftModem library to work with the attiny85, some different names of the PORTs and TMSKs and experiment with different frequencies for the carrier and baudrates.

you can easily check the signals also with audacity. display as spectrogramm and do spectral analysis.

FSK baby check sounds.png

FSK baby peaks.png


We had to do some changes to the SoftModem library... more soon.

With the following speed setting it works fine, but slow:

#define SOFT_MODEM_BAUD_RATE   (50)
#define SOFT_MODEM_LOW_FREQ    (600)
#define SOFT_MODEM_HIGH_FREQ   (850)


some inspiring links:,19648.0.html

Interesting article by tom keene about the iPhone boundary, also talking about the SoftModem approach, but finally just going into the phone with an oscillation.

SoftModem Library

some japanese via android

for iPhone


FSK java script for browsers:

more about FSK, Frequency Shift Keying

abnother one

Turbidity sensor

simple light absorbtion at a specific wavelength of a cheap laser, easy detection of turbidity.

Turbi siech.jpg

turbidity to pd tools:

Turbiditiy logging pd.jpg

New kresse shields.jpg

Commercial Turbidity Sensors

see this for dishwashers...

UV-vis absorbtion spectrophotometer

UV-vis spectrometer, would be even nicer, added white LED instead of laser, changing colors with simple light filters. but they have almost no UV, so added a UV led. turns out the CdS photoresistors are really slow and not very sensitive at UV also...

NS spectrophotometer filtering.jpg

also we are working on a hacked line-scanner to look at the spectra after passing a prism or grating.