3 more days until beta test is officially closed!
Hey everyone, we’re still accepting new signups for the beta test, but we’re going to close applications pretty soon as we begin purchasing parts. So if you’ve been waffling now’s the time to make a move!
Dave and Robert’s work on the detector (show pictures)
Dave Kramer and Robert Zegarac have been working on improving the signal quality on the MultispeQ (the handheld measurement device used in the PhotosynQ platform). Previously, we achieved a peak to peak noise of about 300 ppm which enabled us to easily and effectively measure things like plant fluorescence, but when it came to measuring smaller signals like absorbance at 940nm or 520nm the signals were acceptable but not great. See below for some examples of leaf absorbance at 940 and 520.
Dave and Robert came up with some new ideas for filtering the electronic signal and increasing the number of averages in the ADC to effectively increase the resolution from 13ish bits to 16 bits or higher. Using the same photodiode (ie the part that absorbs the light), we can now get 30ppm (10X better!!!!!) in their
Plus here. The Kramer Lab website is here if you want to learn more about his past and current work.
Updates from Chlorophyll Content (SPAD) measurements
In the last post I talked about the chlorophyll content measurement (aka SPAD aka Soil Plant Analysis Development coined by Minolta who developed the first handheld device) and why it’s useful. Well, we’ve managed to make the MultispeQ measure absorbance at 650 and 940nm necessary for measure chlorophyll content and the initial results are promising. We have not yet correlated actual chlorophyll content measured using extraction with our handheld device (that’s the next step), we have used some Rosco gel filters which have known transmittance values at 650nm (basically plastic sheets of varying colors of green) to see if we are getting values we’d expect. Well – looks pretty good –>
Initial chlorophyll content results using SPAD measurements scale
As one would expect, the light green (high transmission) has higher values while dark green (lower transmission) have lower values, with a y-intercept very near zero. I also measured a couple of leaves of varying greenness (just measured by eye) and the values came out to about what one would expect, which is promising.
If anyone is interested in running a calibration of our device to a Minolta or other SPAD meter, we’d love to see it! If we have time, we’ll do a correlation to actual chlorophyll content sometime before the beta.
Pick and place machine ordered!
No outsourcing for us! We’re doing small batches which will change frequently, and we have other projects in the lab which could use it, so a small-scale pick and place makes sense. We’re getting the slightly larger (28 reel) version of this one, which was demoed by the guys at Dangerous Prototoypes . We’re hoping that it won’t take too long to set up, though we all have a sinking feeling it may be a bit finicky to get started – we will see soon enough!