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Added 3rd order polynomial linear compensation
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Added optinal 3rd order polynomial linear compensation to PS_Voltage
class to help improve ADC linear response.
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@ogiewon
ogiewon committed Sep 1, 2017
1 parent 50b879e commit 6965c28
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Showing 3 changed files with 115 additions and 6 deletions.
87 changes: 82 additions & 5 deletions Arduino/libraries/ST_Anything/PS_Voltage.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -11,7 +11,7 @@
// defaults for this sensor are based on the device used during testing.
//
// Create an instance of this class in your sketch's global variable section
// For Example: st::PS_Voltage sensor1("voltage1", 120, 0, PIN_VOLTAGE, 0, 1023, 0, 5);
// For Example: st::PS_Voltage sensor1("voltage1", 120, 0, PIN_VOLTAGE, 0, 1023, 0.0, 5.0);
//
// st::PS_Voltage() constructor requires the following arguments
// - String &name - REQUIRED - the name of the object - must match the Groovy ST_Anything DeviceType tile name
Expand All @@ -31,6 +31,32 @@
//
// filteredValue = (filterConstant/100 * currentValue) + ((1 - filterConstant/100) * filteredValue)
//
//----------------------------------------------------------------------------------------------------------------------------------------------
// st::PS_Voltage() has a second constructor which includes a 3rd order polynomial compensation algorithm.
//
// Create an instance of this class in your sketch's global variable section
// For Example: static st::PS_Voltage sensor5(F("voltage1"), 5, 1, PIN_VOLTAGE_1, -40, 140, 0, 4095, 20, 75, -0.000000025934, 0.0001049656215, 0.9032840665333, 204.642825355678);
//
// The following arguments all all REQUIRED in order to use the Compensation Algorithm.
// - String &name - REQUIRED - the name of the object - must match the Groovy ST_Anything DeviceType tile name
// - long interval - REQUIRED - the polling interval in seconds
// - long offset - REQUIRED - the polling interval offset in seconds - used to prevent all polling sensors from executing at the same time
// - byte pin - REQUIRED - the Arduino Pin to be used as an analog input
// - double s_l - REQUIRED - first argument of Arduino map(s_l,s_h,m_l,m_h) function to scale the output
// - double s_h - REQUIRED - second argument of Arduino map(s_l,s_h,m_l,m_h) function to scale the output
// - double m_l - REQUIRED - third argument of Arduino map(s_l,s_h,m_l,m_h) function to scale the output
// - double m_h - REQUIRED - fourth argument of Arduino map(s_l,s_h,m_l,m_h) function to scale the output
// - byte numSamples - REQUIRED - number of analog readings to average per scheduled reading of the analog input
// - byte filterConstant - REQUIRED - Value from 5% to 100% to determine how much filtering/averaging is performed 100 = none, 5 = maximum
// - double Coeff1 - REQUIRED - 3rd order polynomial coefficient #1
// - double Coeff2 - REQUIRED - 3rd order polynomial coefficient #2
// - double Coeff3 - REQUIRED - 3rd order polynomial coefficient #3
// - double Coeff4 - REQUIRED - 3rd order polynomial coefficient #4
//
// 3rd order Plynomial Compensation Algorithm (useful for correcting non-linear analog to digital converters)
//
// CompensatedValue = Coeff1 * rawAnalogInput^3 + Coeff2 * rawAnalogInput^2 + Coeff3 * rawAnalogInput + Coeff4
//
// This class supports receiving configuration data from the SmartThings cloud via the ST App. A user preference
// can be configured in your phone's ST App, and then the "Configure" tile will send the data for all sensors to
// the ST Shield. For PollingSensors, this data is handled in the beSMart() function.
Expand All @@ -45,13 +71,15 @@
// 2017-08-18 Dan Ogorchock Modified to return floating point values instead of integer
// 2017-08-31 Dan Ogorchock Added oversampling optional argument to help reduce noisy signals
// 2017-08-31 Dan Ogorchock Added filtering optional argument to help reduce noisy signals
// 2017-09-01 Dan Ogorchock Added 3rd order polynomial nonlinear correction compensation
//
//
//******************************************************************************************
#include "PS_Voltage.h"

#include "Constants.h"
#include "Everything.h"
#include <math.h>

namespace st
{
Expand All @@ -70,7 +98,8 @@ namespace st
SENSOR_HIGH(s_h),
MAPPED_LOW(m_l),
MAPPED_HIGH(m_h),
m_nNumSamples(NumSamples)
m_nNumSamples(NumSamples),
m_bUseCompensation(false)
{
setPin(analogInputPin);

Expand All @@ -90,6 +119,40 @@ namespace st

}

//constructor - called in your sketch's global variable declaration section
PS_Voltage::PS_Voltage(const __FlashStringHelper *name, unsigned int interval, int offset, byte analogInputPin, double s_l, double s_h, double m_l, double m_h, int NumSamples, byte filterConstant, double Coeff1, double Coeff2, double Coeff3, double Coeff4) :
PollingSensor(name, interval, offset),
m_fSensorValue(-1.0),
SENSOR_LOW(s_l),
SENSOR_HIGH(s_h),
MAPPED_LOW(m_l),
MAPPED_HIGH(m_h),
m_nNumSamples(NumSamples),
m_dCoeff1(Coeff1),
m_dCoeff2(Coeff2),
m_dCoeff3(Coeff3),
m_dCoeff4(Coeff4),
m_bUseCompensation(true)
{
setPin(analogInputPin);

//check for upper and lower limit and adjust accordingly
if ((filterConstant <= 0) || (filterConstant >= 100))
{
m_fFilterConstant = 1.0;
}
else if (filterConstant <= 5)
{
m_fFilterConstant = 0.05;
}
else
{
m_fFilterConstant = float(filterConstant) / 100;
}

}


//destructor
PS_Voltage::~PS_Voltage()
{
Expand Down Expand Up @@ -123,11 +186,27 @@ namespace st
{
int i;
double tempValue = 0;
long tempAnalogInput = 0;

//implement oversampling / averaging
for (i = 0; i < m_nNumSamples; i++) {

tempValue += map_double(analogRead(m_nAnalogInputPin), SENSOR_LOW, SENSOR_HIGH, MAPPED_LOW, MAPPED_HIGH);
tempAnalogInput = analogRead(m_nAnalogInputPin);

if (m_bUseCompensation) {

//Serial.print(F("PS_Voltage::tempAnalogInput = "));
//Serial.print(tempAnalogInput);

tempAnalogInput = (m_dCoeff1 * pow(tempAnalogInput, 3)) + (m_dCoeff2 * pow(tempAnalogInput, 2)) + (m_dCoeff3 * tempAnalogInput) + m_dCoeff4;

//Serial.print(F(", PS_Voltage::tempAnalogInput (Compensated) = "));
//Serial.print(tempAnalogInput);
//Serial.println();

}

tempValue += map_double(tempAnalogInput, SENSOR_LOW, SENSOR_HIGH, MAPPED_LOW, MAPPED_HIGH);

//if (st::PollingSensor::debug)
//{
Expand All @@ -149,8 +228,6 @@ namespace st
{
m_fSensorValue = (m_fFilterConstant * tempValue) + (1 - m_fFilterConstant) * m_fSensorValue;
}

//m_fSensorValue = map_double(analogRead(m_nAnalogInputPin), SENSOR_LOW, SENSOR_HIGH, MAPPED_LOW, MAPPED_HIGH);

Everything::sendSmartString(getName() + " " + String(m_fSensorValue));
}
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34 changes: 33 additions & 1 deletion Arduino/libraries/ST_Anything/PS_Voltage.h
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Original file line number Diff line number Diff line change
Expand Up @@ -11,7 +11,7 @@
// defaults for this sensor are based on the device used during testing.
//
// Create an instance of this class in your sketch's global variable section
// For Example: st::PS_Voltage sensor1("voltage1", 120, 0, PIN_VOLTAGE, 0, 1023, 0, 5);
// For Example: st::PS_Voltage sensor1("voltage1", 120, 0, PIN_VOLTAGE, 0, 1023, 0.0, 5.0);
//
// st::PS_Voltage() constructor requires the following arguments
// - String &name - REQUIRED - the name of the object - must match the Groovy ST_Anything DeviceType tile name
Expand All @@ -31,6 +31,32 @@
//
// filteredValue = (filterConstant/100 * currentValue) + ((1 - filterConstant/100) * filteredValue)
//
//----------------------------------------------------------------------------------------------------------------------------------------------
// st::PS_Voltage() has a second constructor which includes a 3rd order polynomial compensation algorithm.
//
// Create an instance of this class in your sketch's global variable section
// For Example: static st::PS_Voltage sensor5(F("voltage1"), 5, 1, PIN_VOLTAGE_1, -40, 140, 0, 4095, 20, 75, -0.000000025934, 0.0001049656215, 0.9032840665333, 204.642825355678);
//
// The following arguments all all REQUIRED in order to use the Compensation Algorithm.
// - String &name - REQUIRED - the name of the object - must match the Groovy ST_Anything DeviceType tile name
// - long interval - REQUIRED - the polling interval in seconds
// - long offset - REQUIRED - the polling interval offset in seconds - used to prevent all polling sensors from executing at the same time
// - byte pin - REQUIRED - the Arduino Pin to be used as an analog input
// - double s_l - REQUIRED - first argument of Arduino map(s_l,s_h,m_l,m_h) function to scale the output
// - double s_h - REQUIRED - second argument of Arduino map(s_l,s_h,m_l,m_h) function to scale the output
// - double m_l - REQUIRED - third argument of Arduino map(s_l,s_h,m_l,m_h) function to scale the output
// - double m_h - REQUIRED - fourth argument of Arduino map(s_l,s_h,m_l,m_h) function to scale the output
// - byte numSamples - REQUIRED - number of analog readings to average per scheduled reading of the analog input
// - byte filterConstant - REQUIRED - Value from 5% to 100% to determine how much filtering/averaging is performed 100 = none, 5 = maximum
// - double Coeff1 - REQUIRED - 3rd order polynomial coefficient #1
// - double Coeff2 - REQUIRED - 3rd order polynomial coefficient #2
// - double Coeff3 - REQUIRED - 3rd order polynomial coefficient #3
// - double Coeff4 - REQUIRED - 3rd order polynomial coefficient #4
//
// 3rd order Plynomial Compensation Algorithm (useful for correcting non-linear analog to digital converters)
//
// CompensatedValue = Coeff1 * rawAnalogInput^3 + Coeff2 * rawAnalogInput^2 + Coeff3 * rawAnalogInput + Coeff4
//
// This class supports receiving configuration data from the SmartThings cloud via the ST App. A user preference
// can be configured in your phone's ST App, and then the "Configure" tile will send the data for all sensors to
// the ST Shield. For PollingSensors, this data is handled in the beSMart() function.
Expand All @@ -45,6 +71,7 @@
// 2017-08-18 Dan Ogorchock Modified to return floating point values instead of integer
// 2017-08-31 Dan Ogorchock Added oversampling optional argument to help reduce noisy signals
// 2017-08-31 Dan Ogorchock Added filtering optional argument to help reduce noisy signals
// 2017-09-01 Dan Ogorchock Added 3rd order polynomial nonlinear correction compensation
//
//
//******************************************************************************************
Expand All @@ -63,11 +90,16 @@ namespace st
double SENSOR_LOW, SENSOR_HIGH, MAPPED_LOW, MAPPED_HIGH;
int m_nNumSamples;
float m_fFilterConstant; //Filter constant % as floating point from 0.00 to 1.00
double m_dCoeff1, m_dCoeff2, m_dCoeff3, m_dCoeff4; //3rd order polynomial nonlinear correction compensation coefficients
bool m_bUseCompensation;

public:
//constructor - called in your sketch's global variable declaration section
PS_Voltage(const __FlashStringHelper *name, unsigned int interval, int offset, byte analogInputPin, double s_l=0, double s_h=1023, double m_l=0, double m_h=5000, int NumSamples=1, byte filterConstant = 100);

//constructor with 3rd order polynomial nonlinear correction compensation coefficients - called in your sketch's global variable declaration section
PS_Voltage(const __FlashStringHelper *name, unsigned int interval, int offset, byte analogInputPin, double s_l, double s_h, double m_l, double m_h, int NumSamples, byte filterConstant, double Coeff1, double Coeff2, double Coeff3, double Coeff4);

//destructor
virtual ~PS_Voltage();

Expand Down
Binary file added ESP32-Voltage-vs-ADC-Reading.xlsx
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