3 ms·
Two ways to make it: - know the total length of the tape, and when it's changed, and therefore predict the current radius of the roll - a small sprung variabl
by samwillis 1y ago
Two ways to make it:
- know the total length of the tape, and when it's changed, and therefore predict the current radius of the roll
- a small sprung variable resistor pressing against the under side of the role
But that could be over-engineering something that almost more perfect if it's a little imperfect.
- fecal_henge 1y agoId just weigh the roll.
- ekaryotic 1y agothought of a third way: cellophane tape does emit xrays when unrolled, so correlate the strength of the radiation with the angular velocity of the roll to more precisely calculate how much tape was removed. I suspect a second photodiode may respond to the radiation.