Comments

Author Comment Last activity Moderation
donblair "Hallo! I haven't had great luck with Digikey shopping carts sticking around, so it might be better to put direct links to parts in e.g. a wiki ......" | Read more » almost 8 years ago
donblair "Hi Rebeccah! Fantastic stuff here. Lots to digest, and I have several thoughts -- but first, quickly: the frequency output of the Coqui requires..." | Read more » almost 8 years ago
donblair "Ben, Fantastic job on this! Excellent descriptions of the entire system -- the electronics, the probe design, and the calibration procedure. Ver..." | Read more » about 8 years ago
donblair "Hah, just saw that @mathew posted a link I was reading this morning, but forgot to include: http://www.electroschematics.com/6923/555-low-voltage-..." | Read more » over 8 years ago
donblair "Oh gosh -- Chris, thanks for tagging me in this thread -- I had no idea that this existed! Wow, Ed -- what amazing work you've been doing!! It's ..." | Read more » over 8 years ago
donblair "Oh, toilet tank analogy is great! @cversek was talking at LEAFFEST about how, in the water <--> electricity analogy, the only sticking point..." | Read more » almost 10 years ago
donblair "Aw, shucks :) But yes, it's so cool that we might find some part of design solution space that satisfies all of these! Before Ben pointing me to t..." | Read more » almost 10 years ago
donblair "Here's an example of a cheap, through-hole 'trimmer capacitor': http://www.amazon.com/Through-Trimmer-Variable-Capacitors-Brown/dp/B00G9BJTJW/ref=..." | Read more » almost 10 years ago
donblair "Ah darnit, I deleted my comment above by accident, instead of editing it ... Okay, the punchline is: The only ways to compensate for the effect t..." | Read more » almost 10 years ago
donblair "My endocrine system can't handle all of these ups and downs. But tonight ends on an up. " | Read more » almost 10 years ago
donblair "UPDATE: We can dial in the capacitance! Ben pointed me to the fact that 'trimmers' exist: http://www.mouser.com/ProductDetail/Murata/TZB4R500EA1..." | Read more » almost 10 years ago
donblair "Yes! And before, when we had a different relationship between freq and conductivity, the only way to do that tuning was to tweak the probe -- and J..." | Read more » almost 10 years ago
donblair "(maybe that should prompt me to reconsider my life direction?) " | Read more » almost 10 years ago
donblair "YES! :) I was dancing around with glee last night when I saw the equation for freq vs. resistance and capacitance for the 50% duty cycle! " | Read more » almost 10 years ago
donblair "Ah, this is all so great! This brings up a bunch of interesting issue for me that I'd love to get feedback on. Naming conventions. Maybe it'd be..." | Read more » almost 10 years ago
donblair "Yay! @mathew: Great! And we already have a pretty nice relevant smt board design -- coin cell powered, with an RGB led and a piezo buzzer: http..." | Read more » about 10 years ago
donblair "Also: how hard would it be to rig up some sort of 'pen' that connects to a 555 and writes out a 'record' of the conductivity on some physical mediu..." | Read more » about 10 years ago
donblair "ZOMG that's brilliant. I'm going to try to bring the materials required to do a rough prototype of this to Plymouth -- but anyway shouldn't be hard..." | Read more » about 10 years ago
donblair "E.g. I just found this: http://wiki.openmusiclabs.com/wiki/PWMDAC And, oh gosh, this is fun: http://sensorium.github.io/Mozzi/ And: http://www.ucho..." | Read more » about 10 years ago
donblair "Good call on the power control chip -- for the riffle-ito design, I'm just using an LDO, which should provide a relatively clean signal? But yeah,..." | Read more » about 10 years ago
donblair "Egads! Mat, thanks for pointing this out! I totally flubbed that one: in the 555 approach, the signal that is passing through the water is indee..." | Read more » about 10 years ago
donblair "Ah -- great thoughts! And your comment points to an important issue, which is that I myself was unclear (and still am, a bit) as to the utility of..." | Read more » about 10 years ago
donblair "Cversek -- wow, thank you!!! What a useful collection of info. Your note convinced Ben to add a dual op-amp to buffer the conductivity output, and..." | Read more » over 10 years ago
donblair "Just noticed -- in that last plot, it looks like the 'falling times' (top curve) start 'slumping', whilie the 'rising times' (bottom curve) seem re..." | Read more » over 10 years ago