Minimalist low-pass filter library

So, the other day I needed to compute some low-pass filters on the fly on an Arduino Mega. By “on the fly” I mean that the filters’ parameters would eventually be recomputed mid-operation, so setting some equation with static const parameters would not cut it. Using a static filter, is, however, the most common application scenario. If that’s your case – and I insist – tweak the sh*t out of your filter with a decent tool then just add it to your code. If, on the other hand, you need to update your filter dynamically (or if you’re just plain lazy to compute poles and zeros), then this is for you.

I ended up putting together a minimalist library for that, libFilter (github!). Works with the Arduino IDE and as a regular C++ library (just uncommenting one #define does the trick).

Using two filter instances on a signal from a load cell getting punched.

Using two filter instances on a signal from a load cell getting punched.

For now it only implements low-pass filters based on  normalized butterworth polynomials, but who knows what necessity might add to it next. Let’s take a look at some ADC filtering:

’til next time!

P.S.: I just can’t avoid letting this page eventually fall into temporary ostracism. Geez.

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