#include <AH/Hardware/FilteredAnalog.hpp>
A class that reads and filters an analog input.
A map function can be applied to the analog value (e.g. to compensate for logarithmic taper potentiometers or to calibrate the range). The analog input value is filtered using an exponential moving average filter. The default settings for this filter can be changed in Settings.hpp.
After filtering, hysteresis is applied to prevent flipping back and forth between two values when the input is not changing.
Precision | The number of bits of precision the output should have. |
FilterShiftFactor | The number of bits used for the EMA filter. The pole location is \( 1 - \left(\frac{1}{2}\right)^{\text{FilterShiftFactor}} \). A lower shift factor means less filtering ( \(0\) is no filtering), and a higher shift factor means more filtering (and more latency). |
FilterType | The type to use for the intermediate types of the filter. Should be at least \( \text{ADC_BITS} + \text{IncRes} + \text{FilterShiftFactor} \) bits wide. |
AnalogType | The type to use for the analog values. Should be at least \( \text{ADC_BITS} + \text{IncRes} \) bits wide. |
IncRes | The number of bits to increase the resolution of the analog reading by. |
Definition at line 272 of file FilteredAnalog.hpp.
Public Types | |
using | MappingFunction = AnalogType (*)(AnalogType) |
A function pointer to a mapping function to map analog values. | |
Public Member Functions | |
FilteredAnalog (pin_t analogPin, AnalogType initial=0) | |
Construct a new FilteredAnalog object. | |
FilteredAnalog (ArduinoPin_t analogPin, AnalogType initial=0) | |
Construct a new FilteredAnalog object. | |
FilteredAnalog () | |
Construct a new FilteredAnalog object. | |
void | invert () |
Invert the analog value. | |
void | reset (AnalogType value=0) |
Reset the filter to the given value. | |
void | resetToCurrentValue () |
Reset the filtered value to the value that's currently being measured at the analog input. | |
void | map (MappingFunction fn) |
Specify a mapping function/functor that is applied to the analog value after filtering and before applying hysteresis. | |
MappingFunction & | getMappingFunction () |
Get a reference to the mapping function. | |
const MappingFunction & | getMappingFunction () const |
Get a reference to the mapping function. | |
bool | update () |
Read the analog input value, apply the mapping function, and update the average. | |
AnalogType | getValue () const |
Get the filtered value of the analog input (with the mapping function applied). | |
float | getFloatValue () const |
Get the filtered value of the analog input with the mapping function applied as a floating point number from 0.0 to 1.0. | |
AnalogType | getRawValue () const |
Read the raw value of the analog input without any filtering or mapping applied, but with its bit depth increased by IncRes . | |
Static Public Member Functions | |
static constexpr AnalogType | getMaxRawValue () |
Get the maximum value that can be returned from getRawValue. | |
static void | setupADC () |
Select the configured ADC resolution. | |
Private Types | |
using | EMA_t = EMA<FilterShiftFactor, AnalogType, FilterType> |
Private Member Functions | |
template<typename M = MappingFunction> | |
std::enable_if< std::is_constructible< bool, M >::value, AnalogType >::type | mapFnHelper (AnalogType input) |
Helper function that applies the mapping function if it's enabled. | |
template<typename M = MappingFunction> | |
std::enable_if<!std::is_constructible< bool, M >::value, AnalogType >::type | mapFnHelper (AnalogType input) |
Helper function that applies the mapping function without checking if it's enabled. | |
Private Attributes | |
pin_t | analogPin |
MappingFunction | mapFn |
EMA_t | filter |
Hysteresis< ADC_BITS+IncRes - Precision, AnalogType, AnalogType > | hysteresis |
using MappingFunction = AnalogType (*)(AnalogType) |
A function pointer to a mapping function to map analog values.
Definition at line 306 of file FilteredAnalog.hpp.
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privateinherited |
Definition at line 215 of file FilteredAnalog.hpp.
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inline |
Construct a new FilteredAnalog object.
analogPin | The analog pin to read from. |
initial | The initial value of the filter. |
Definition at line 285 of file FilteredAnalog.hpp.
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inline |
Construct a new FilteredAnalog object.
analogPin | The analog pin to read from. |
initial | The initial value of the filter. |
Definition at line 291 of file FilteredAnalog.hpp.
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inline |
Construct a new FilteredAnalog object.
This constructor should not be used.
It is just a way to easily create arrays of FilteredAnalog objects, and initializing them later. Trying to update a default-constructed or uninitialized FilteredAnalog object will result in a fatal runtime error.
Definition at line 302 of file FilteredAnalog.hpp.
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inline |
Invert the analog value.
For example, if the precision is 10 bits, when the analog input measures 1023, the output will be 0, and when the analog input measures 0, the output will be 1023.
map
method. Definition at line 315 of file FilteredAnalog.hpp.
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inlineinherited |
Reset the filter to the given value.
value | The value to reset the filter state to. |
Definition at line 70 of file FilteredAnalog.hpp.
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inlineinherited |
Reset the filtered value to the value that's currently being measured at the analog input.
This is useful to avoid transient effects upon initialization.
Definition at line 83 of file FilteredAnalog.hpp.
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inlineinherited |
Specify a mapping function/functor that is applied to the analog value after filtering and before applying hysteresis.
fn | This functor should have a call operator that takes the filtered value (of ADC_BITS + IncRes bits wide) as a parameter, and returns a value of ADC_BITS + IncRes bits wide. |
Definition at line 105 of file FilteredAnalog.hpp.
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inlineinherited |
Get a reference to the mapping function.
Definition at line 110 of file FilteredAnalog.hpp.
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inlineinherited |
Get a reference to the mapping function.
Definition at line 114 of file FilteredAnalog.hpp.
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inlineinherited |
Read the analog input value, apply the mapping function, and update the average.
true | The value changed since last time it was updated. |
false | The value is still the same. |
Definition at line 125 of file FilteredAnalog.hpp.
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inlineinherited |
Get the filtered value of the analog input (with the mapping function applied).
Precision
bits wide. Definition at line 143 of file FilteredAnalog.hpp.
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inlineinherited |
Get the filtered value of the analog input with the mapping function applied as a floating point number from 0.0 to 1.0.
Definition at line 152 of file FilteredAnalog.hpp.
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inlineinherited |
Read the raw value of the analog input without any filtering or mapping applied, but with its bit depth increased by IncRes
.
Definition at line 160 of file FilteredAnalog.hpp.
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inlinestaticconstexprinherited |
Get the maximum value that can be returned from getRawValue.
Definition at line 172 of file FilteredAnalog.hpp.
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inlinestaticinherited |
Select the configured ADC resolution.
By default, it is set to the maximum resolution supported by the hardware.
Definition at line 183 of file FilteredAnalog.hpp.
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inlineprivateinherited |
Helper function that applies the mapping function if it's enabled.
This function is only enabled if MappingFunction is explicitly convertible to bool.
Definition at line 196 of file FilteredAnalog.hpp.
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inlineprivateinherited |
Helper function that applies the mapping function without checking if it's enabled.
This function is only enabled if MappingFunction is not convertible to bool.
Definition at line 207 of file FilteredAnalog.hpp.
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privateinherited |
Definition at line 212 of file FilteredAnalog.hpp.
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privateinherited |
Definition at line 213 of file FilteredAnalog.hpp.
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privateinherited |
Definition at line 229 of file FilteredAnalog.hpp.
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privateinherited |
Definition at line 231 of file FilteredAnalog.hpp.