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55 lines
1.7 KiB
Markdown
55 lines
1.7 KiB
Markdown
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# AnalogPin
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Arduino library to add functionality on top of analogRead()
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## Description
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AnalogPin is an Arduino class that adds noise filtering and smoothing
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to analogRead().
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Furthermore it can speed up the analogRead() function by tuning the prescaler.
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This latter is AVR only.
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## Operation
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**readLast()** returns the last read value without reading a new one.
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**get/setPrescaler(prescale)** can be used to speed up analogRead().
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The effect is that both the accuracy and precission are affected.
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You should verify if this is acceptable for your project.
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***Works only for AVR based boards***
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**get/setNoiseThreshold(noise)** is used to set the noise threshold to be used by
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the **read()** function.
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**read(twice)** implements an **analogRead()** that supresses small noise fluctuations.
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The parameter twice is used to force analogRead() to be executed twice to reduce noise
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from the multiplexing.
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Example: if the previous read has the value 300 and you
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want to interpret all subsequent readings between 290
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and 310 as 300 (the same) your code should look like:
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```
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AP.setNoiseThreshold(10);
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AP.read();
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```
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**get/setSmoothWeight(alpha)** is used to set the weight factor for the **readSmoothed()** function.
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The weight of the previous read is **alpha/32**.
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A higher alpha will dampen the signal more, a lower alpha
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will follow the actual signal better.
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This can be used to suppress noise too.
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```
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AP.setSmoothWeight(4); // weight = 4/32 = 1/8 = 12.5%
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AP.readSmoothed();
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```
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**readSmoothed()** implements an analogRead with a running average build in.
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Two functions that expose information that might sometimes be useful.
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**readPrevious()** returns the previous value read.
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**readLast()** returns the last value read.
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