Measure the mass of an eyelash with a DIY microbalance
Why Hacker News recommends it
Pointed to as proof that you can weigh micrograms cheaply at home, and as a clear breakdown of how such a scale works.
What it is
Ben Krasnow of Applied Science builds a DIY microbalance from an analog panel meter with an optical servo loop. It reaches about 5 micrograms of precision and is used to weigh a single eyelash at around 35 micrograms.
Recommended by 1 HN commenters across 1 different months, 2018 to 2026.
What Hacker News said
Recommends jcims · 2018-12 · on “Making Penicillin at Home”
Saw this DIY one a few years back on youtube, looks like the Erowid one, thought it was a neat build - [LINK] YouTube just dug up a a real nice breakdown that Ben Krasnow did - [this video]
Cites mikewarot · 2023-07 · on “An Invitation to a Secret Society”
Measuring things precisely is way cheaper than it's ever been. You can weigh micrograms without too much effort.[1] You can buy time/frequency standards for $200 or so that time to the national standards.[2] Float glass is a cheap and relatively flat surface plate that you can buy almost anywhere. Lasers, detectors, computing, everything is dirt cheap compared to the past. If you have something you want to make, or measure, this is likely the easiest time ever to do so. Don't worry about being at the leading edge, just do something, have fun, and you might be the first to notice some weird little quirk that turns out to be important. [1] [this video] [2] [LINK]
Cites s0rce · 2025-05 · on “Strain gauge made out of PCB”
My dad built one with an electromagnetic coil many years ago, can't find the design, capacity was limited but had 100? microgram resolution, maybe similar to this applied science video [this video] but I think simpler. maybe something like this: [LINK] [LINK] I found some old emails about the scale from 2005/6 but can't find the link and it would probably be gone anyways.
Cites pvillano · 2026-01 · on “A4 Paper Stories”
Paper's uniform mass per area makes it useful calibrating very tiny scales. 1mm² of 80 gsm paper will weigh about 80 micrograms. "Measure the mass of an eyelash with a DIY microbalance" by Applied Science [this video]