I've been getting into hydroponics lately and want to start getting quantitative measurements of the specific mineral consumption in each plant. what I have noticed is that the leaf tips eventually get salted due to excess minerals. the options I see so far are this1- open source hacked quantum usb spectrometer (expensive)2- used spectrometer from ebay (expensive and risky)3- pocket diffraction grating spectroscope with a reference light and a camerathe plan is to get a sample cuvette and fill it with known concentrations to calibrate the sensor. the problem I have is whether or not the 0-255 range color channels in the image will even give a decent measurement range for the 0-3000 ppm total dissolved solids for the high end of the sensing range.is this something reasonably achievable with a crude setup just to prove it out, or is there some fundamental physics thing which means I would need a huge machine to get quantitative measurements from a spectroscope/spectrometer? I've only ever seen them used as a go/no-go measuring tool, not so much a quantitative measurement. I'm aware of projects like PySpectrometer...I really don't want to do titrations on 50 buckets of hydroponic solution once a week.
>>17065646to be clear-I have a TDS/EC meter, but my concern is that the mineral consumption is not uniform across the minerals in solution, nor across plants. TDS/EC is good for short term stuff, but I need to know which specific mineral to add back to prevent salting the plant by adding broad spectrum hydroponic feed.
>>17065646make a raspberry pi onehttps://youtu.be/T_goVwwxKE4https://youtu.be/Tw3HJEhE2dIhttps://youtu.be/SCp9T8NKfnM
>>17065686>raspberry pithat project came up in my searches... looks cool and all, but it seems like it will be a money pit in the end with bad results. there were a few which used a high accuracy photocell and a mirror to measure each wavelength, which means some sort of stepper motor thing. it all gets out of control and is too much to see if it would even be measurable at all.from what I can tell, spectrophotometry and other wavelength measurement techniques can do this, its just that I cannot find any ready reference manuals or people who know.I might just end up buying a batch of titration reagents and just do that with a color chart.
