New battery test, day 650: 2.86 volts. Number go down! But even when number go down, watch can still function just fine, down to 1.62 volts (which realistically we won’t get to until the battery has but minutes left). If I had to guess, I’d guess I have 30% of my CR2016’s capacity remaining, which means we should easily make it to the two year mark, and I should be able to wear it all semester and well into the summer. If I’m being bold? I think it‘ll tick from February 2022 to September 2024. 🤞🏽
New battery test, day 625: 2.89 volts. Technically day 626, and probably closer to 2.885, but I intended on logging every 25 days, so there you have it. Ben reports from Paris that his watch (yellow line) died just a few days ago, which I think means I can estimate battery life between 1.7 and 2+ years, depending on how my watch does.
New battery test, day 873: it's over! Feels poetic that the battery died at #HOPE. (Also I was demo'ing it all afternoon at the @crowdsupply table.) I actually logged the battery yesterday at 2.19 volts — low enough that the LAP indicator was on, which meant the battery was on its last legs. Point is, the February 2022 firmware lasted 2.4 YEARS on a single 100 mAh coin cell, which is not bad! I'm now ready to claim 1.7 to 2.4 years of battery life — and that's backed by real-world testing :)
New battery test, en route to @crowdsupply#teardown at day 850: 2.52 volts. I missed the check-in at day 800 (2.72 V) but the trend line is clear: it’s going down. Probably 8% of charge left. I’m guessing I’ve got another 74 days on this coin cell, which puts it dying in early September. With some luck — and a lot more hard work — I might just have Sensor Watch Pro ready by then. 🤞🏽
New battery test, day 700: 2.84 volts, as I extend the X-axis another hundred days.
I now have enough data to posit that 2.85 volts is the 70% mark for battery exhaustion: old firmware hit it on day 300 and died on day 425; Ben's watch hit it at day 440 and died at day 622. By that math, I predict 292 days remain, for a death date around November 8th. Which means this little watch that could might just make it to its THIRD @hackaday Supercon on a single CR2016 coin cell.
Okay, so, #Supercon. Inclusion. First I want to say this thread is NOT meant to detract from the respect I have for the folks presenting. But pixels have been lit about the general white/maleness of the speaker lineup, and it's worth unpacking. In over two dozen talks, there are only three women, and no Black presenters. It's frustrating because it doesn't reflect the diversity I see in my community. And yet I also recognize where I've failed on this account myself. We have work to do; a THREAD:
Folks: we’re getting closer! This print was 0.6 mm off — forgot to set the PCB thickness parameter to 1mm - but I’m starting a new print now that I can play with a week from Monday. (Why that long? I’m going off-grid next week for a much needed vacation.) Anyway, OpenSCAD script is now decent enough to share. Sorry it’s kind of mayhem; I’ve been hacking on it piecemeal for ages… https://gist.github.com/joeycastillo/1835151d5760fa730ffa566defb53698