"Voltmitten": an amateur overdesigns a DC voltage monitor

Tom Stepleton stepleton at gmail.com
Sun Dec 26 11:41:22 CST 2021

Hi cctalk,

Ever since CuriousMarc put out his YouTube horror film last April
about a killer
HP 9825T power supply
I've been worrying about how my own comparably-aged systems might avoid a
similar fate, at least until I have the wherewithal to do a Jerry Walker
high-quality PSU refurbishment.

In the end, borrowing a tactic from Commodore fans, I made a circuit that
sits between a DC power supply and a load and cuts off the power if it
senses an overvoltage or an undervoltage condition. I'm happy to share it
with you now, with the usual anxiety amateurs feel when an audience
includes some professionals. I hope at least some elements of the design
can be useful! Here it is: https://github.com/stepleton/voltmitten/

(There are two reasons for the name "Voltmitten". One is that the gizmo is
shaped a bit like a hand. The other is to remind you that it wasn't really
designed by the most serious practitioner.)

You can see my cute mock video advert for Voltmitten here:
I hope it's an adequate homage to Marc's inspiring videos. Most of the
effort here went into a brief gag view of a carefully rotoscoped
<https://twitter.com/tstepleton/status/1475093211983097860> Bob Stern aka
"Mr. Fancy Pants", which may not have been the best use of time but is at
least a result I can feel proud of :-)

With best wishes for a bright 2022,

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