I do not have any problem but I found a solution to a problem I have had - hopefully someone else will find it useful. I have bought some 4x4 16 key matrix membrane keypads - see image. They are very cheap and very useful – but interface to them require normally 4+4=8 ports. I can use normal charl…

Extended Charlieplexing

system August 15, 2013, 3:25pm 2

Thought this was worth bringing to the top. Excellent schematic, description and code.

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