Made a hi-res pressure sensor matrix foil from cheap materials

[baltersice]

Cheap being a relative term ... Paid ~ 300 EUR for all the copper tape, but commercial units with lower resolution cost thousands.
Generally an interesting project, that I though was worth a video

[mikeselectricstuff]

Maybe capacitive sensing across a non-conducting soft material could be a better option.
Someone at the Hackaday Unconference last weekend showed this for pressure sensing in shoes to assist people with balance problems

[baltersice]

Thought about that too! With a good uniform 'rubber' mat that compresses proportionally to weight I could just measure capacitance between both sides. But that's about as far as that idea went. Because I have no idea how that could be done economically. 

Probably with vertical and horizontal stripes too? And then something ACish to one of 180 cols to measure miniscule ACish voltages on all rows?

[mikeselectricstuff]

There are plenty of capsensing solutions out there - may even be cheapest to have one chip per zone based on how many sensing lines it can deal with, and tile these as necessary. maybe just have sensing on one side to a common groundplane.
 
The nice thing about capacitance is it can be completely sealed from the compression medium so not rely on electrical contact, and the compression medium is probably going to be cheaper, and you have a much wider choice of materials.

[kosine]

Could have been a nice application for quantum tunneling composite, but it never seems to have been made widely available. (https://en.wikipedia.org/wiki/Quantum_tunnelling_composite) Used to be about 50p per 4x4x1mm "pill" in the UK, but no longer seems available.

Really cool stuff, just basically nickel filaments in a rubber binder. Resistance goes from near infinity to near zero with fingertip pressure. I think the original patents must have expired by now, so maybe it'll get a renaissance.

You can make a poor man's version with iron filing and latex, but you need to align the filings vertically with a magnet whilst the latex cures. (I've had reasonable success with a few seconds in a microwave.) Not as good as the QTC, and it rusts over time.