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80 lines
3.2 KiB
Markdown
80 lines
3.2 KiB
Markdown
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[](https://github.com/marketplace/actions/arduino_ci)
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[](https://github.com/RobTillaart/AnalogPin/actions/workflows/arduino-lint.yml)
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[](https://github.com/RobTillaart/AnalogPin/actions/workflows/jsoncheck.yml)
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[](https://github.com/RobTillaart/AnalogPin/blob/master/LICENSE)
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[](https://github.com/RobTillaart/AnalogPin/releases)
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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 to analogRead().
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Furthermore it can speed up the analogRead() function by tuning the pre-scaler.
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This latter is AVR only.
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## Interface
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- **AnalogPin(uint8_t pin)** constructor with analogue pin as parameter.
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- **void setPrescaler(uint8_t prescale = 7)** AVR only pre-scaler.
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- **uint8_t getPrescaler()** return pre-scaler set.
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- **void setNoiseThreshold(uint8_t noise = 0)** set noise level that should be ignored. Typical 0..2.
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- **uint8_t getNoiseThreshold()** return set value.
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- **void setSmoothWeight(uint8_t alpha = 0)** alpha = 0..31, parameter for low pass filter.
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- **uint8_t getSmoothWeight(void)** returns set alpha.
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- **int read(bool twice = false)** read function, optional read twice to stabilize.
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- **int readSmoothed()** read version that uses low pass filter.
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- **int readPrevious()** returns previous read value.
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- **int readLast()** returns last read value without reading a new one.
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## Operation
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**get/setPrescaler(uint8_t prescale)** can be used to speed up analogRead().
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The effect is that both the accuracy and precision 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(uint8_t noise)** is used to set the noise threshold to be used by the **read()** function.
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**read(bool twice)** implements an **analogRead()** that suppresses small noise fluctuations.
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The parameter twice is used to force analogRead() to be executed twice to reduce noise 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(uint8_t 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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## Future
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- update documentation
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- advantage of certain functions, when to use
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- more examples
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- **volts()** + get/setFactor(float f)
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- move code to .cpp
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