12 – square-inch version ordered ✔

A project log for Universal undervoltage lockout up to 34V input

Feature-packed over-discharge protection. Set the cell-count, minimum cell voltage and dip-time below threshold. Fully hackable!

JanJan 08/15/2019 at 10:330 Comments

Update – 20190826

You always seem to find errors when it's too late for changes :)

The right way would've been: using the internal pull-up and switching to GND...

Update – 20190816

Today I finished my square inch design and ordered it at Aisler:

online shop rendering

This time I added a stainless stencil for top and bottom because I hate adding solder paste with a toothpick or syringe :)

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For a few of my planned projects I need the board to be quite small. So I made a very basic version. It misses all the nice "usability" features, the bigger board has.


The cut-off parameters are set once while programming (and can of course be re-programmed) and there are not LEDs to show the state of the board.

Off-current should be well below 10µA, working-current will be around 1mA when measuring, which is around 10% of the time (while not measuring the Attiny shuts down), so let's assume the working current is around 15% of 1mA, so 0.15mA averaged over time...

The board is 25x25mm in size, it will fit into many many tight spots!