DIY turbidity meters
- 1 Spectroscope
- 2 BabyTurbiduino aka Daphna-2-MIDI Converter
- 3 Turbidity sensor
- 4 UV-vis absorbtion spectrophotometer
BabyTurbiduino aka Daphna-2-MIDI Converter
See more info and file on Thingyverse
Files for Ardunio and pd File:Turby files.zip
Some bugs in the cuvette:
Testing different yeast culture densities:
Tests with Bengt et al
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!
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:
the free software Sigmira is kinda useful to test http://www.saharlow.com/technology/sigmira/
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.
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) #define SOFT_MODEM_MAX_RX_BUFF (32)
some inspiring links:
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. http://www.theanthillsocial.co.uk/sites/theanthillsocial.co.uk/files/TheAppleBarrierTomKeene.pdf
more about FSK, Frequency Shift Keying
simple light absorbtion at a specific wavelength of a cheap laser, easy detection of turbidity.
turbidity to pd tools:
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...
also we are working on a hacked line-scanner to look at the spectra after passing a prism or grating.