Comments

Author Comment Last activity Moderation
donblair "I need a little help understanding this background. When you modulate the LED at 1 kHz, that means it's flashing on and off 1000 times a second? E..." | Read more » over 4 years ago
donblair "This is so great. Quick question: I could imagine extending the battery on a Mobius by controlling a USB power source with a switch: i.e., one c..." | Read more » over 4 years ago
donblair "@pdhixenbaugh -- These are great ideas / questions / suggestions! I just posted a quick follow-up here: https://publiclab.org/notes/donblair/03-2..." | Read more » over 4 years ago
donblair "-- a CR1220 coin cell. " | Read more » over 4 years ago
donblair "Oh, exciting ... it'd be fun to demonstrate anything powered by moving water. Maybe this thingy should be ordered immediately. A visit ASAP sound..." | Read more » over 4 years ago
donblair "Exactly. Was confusing for me, too, as I'd been nursing a rather fixed mental picture of a parallel plate capacitor with a dielectric slab sandwic..." | Read more » over 4 years ago
donblair "This sounds like it might prompt a PVOS research trip up to Bernie Country ... I need to write up a research note, but here's the basic idea (cour..." | Read more » over 4 years ago
donblair "Hi @gretchengehrke :) I'd never really testing it very thoroughly, and I haven't done sufficient background research to know if the 555 approach I..." | Read more » over 4 years ago
donblair "Wow, amazing note. Thanks so much for putting all this so nicely together, @mathew!!! Still digging in, but quick thoughts: The 6-32 screws wit..." | Read more » over 4 years ago
donblair "@pdhixenbaugh -- Good point! I do think the self-discharge rate on these various battery chemistries does differ, but I don't know by how much. Le..." | Read more » over 4 years ago
donblair "Hey All! Okay, after a bunch of discussion last night, it seems that the above P-Mos circuit will work, but the battery leakage is significant. A..." | Read more » over 4 years ago
donblair "Further elaboration on this circuit solution: The idea (nicely described in the blog post) is to use a P-channel Mosfet arranged so that when USB ..." | Read more » over 4 years ago
donblair "(Also note: I've added an extra capacitor to the circuit, so that I'll have a 10uF close to the lithium charger, and on both sides of the LDO) " | Read more » over 4 years ago
donblair "Okay, here's my interpretation of the more advanced circuit: Full schematic: Close-up on the relevant power circuitry: Load balancing is ac..." | Read more » over 4 years ago
donblair "For further reference (both of the below pics are from the above-referenced blog post, the minimal schematic for the charger chip (which I'd been u..." | Read more » over 4 years ago
donblair "Update: What I'd observed was that the previous version of the riffle -- 0.96 -- seemed to allow for USB programming even when a battery wasn't pl..." | Read more » over 4 years ago
donblair "Update: I've attempted to incorporate both the fix to the switch, and the new diode-based power management strategy, in the Riffle 0.1.4 schematic..." | Read more » over 4 years ago
donblair "Update -- based on some tinkering, and some great feedback from folks on the plots-waterquality google group: The power issues no longer seem myst..." | Read more » over 4 years ago
donblair "Also need to add CERN open hardware license info to board artwork " | Read more » almost 5 years ago
donblair "Ah, yes -- just now seeing Mathew's email -- we should also put a grid of pinout artwork on the back, corresponding to the arrangement of the pins ..." | Read more » almost 5 years ago
donblair "Great to see the photos -- thanks for taking them so quickly! Quick items: Looks from the photo that the USB part did in fact stay within the ~ ..." | Read more » almost 5 years ago
donblair "Hey Liz! Wow -- this looks great! Since this research note was originally posted, there are a few insights that have emerged: Silicone doesn't ..." | Read more » almost 5 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 » almost 5 years ago
donblair "@pdhixenbaugh -- the latest version of the Riffle (Beta 0.1.1) will have two battery ports -- one for rechargeable Lipos, and one that can take in ..." | Read more » almost 5 years ago