Controller sketches for the frankenpedals
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Controller sketches for the frankenpedals

The goal is to get a valid reading from the pedals every time, so I'm focusing on fixing readPin() to return the most accurate reading I can.

It used to use this algorithm:

    read pin N times, storing into array dP
    sort dP in ascending order
    generate average of the lower 60% of dP
    generate stddev of lower 60% of dP
while loop count < 5 and stddev is too high

The acceptable stddev is based on what the read value is, since there's a built-in error tolerance on the resistors.

This was not especially fast, as the sort was a bit long.

Now, it uses a set of slots matching the number of input states (14, for 13 pedals + a no-input state).

What it does now, in pseudocode, is:

   add one to dataPoint for pin read

return index of dataPoint with highest count

Since the pins tend to return a bell curve around the actual pin closed (esp with the lower resistances, with the greater error tolerances) we will generally get the right pin.

It uses a FASTADC switch currently; this allows 60 reads in 3 ms, with a pretty high accuracy when the stddev algorithm is used. Not sure if I'm overengineering the reads; maybe I'd do better with better hardware (resistors with lower error tolerances might fluctuate far less).