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/*
* Author: Jon Trulson <jtrulson@ics.com>
* Copyright (c) 2015 Intel Corporation.
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
* LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
* OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
* WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
#pragma once
#include <string>
#include <mraa/aio.h>
namespace upm {
/**
* @brief OTP538U IR Temperature Sensor library
* @defgroup otp538u libupm-otp538u
* @ingroup seeed analog light hak
*/
/**
* @library otp538u
* @sensor otp538u
* @comname OTP538U IR Temperature Sensor
* @altname Grove IR Temperature Sensor
* @type light
* @man generic
* @con analog
* @kit hak
*
* @brief API for the OTP538U IR Temperature Sensor
*
* UPM module for the OTP538U IR temperature sensor
*
* This module was tested with the Grove IR non-contact temperature
* sensor.
*
* The sensor provides 2 analog outputs: one for the thermistor
* that measures the ambient temperature, and the other for the thermopile
* that measures the object temperature.
*
* Much of the code depends on analyzing Seeed Studio* examples
* and the circuit design. As a result, there are several 'magic'
* numbers derived from their circuit design. These values are used
* by default.
*
* The tables used came from the "538U VT
* Table__20_200(v1.3).pdf" and "538RT_table.pdf" datasheets.
*
* These tables assume the object to be measured is 9 cm (3.54
* inches) from the sensor.
*
* @image html otp538u.jpg
* @snippet otp538u.cxx Interesting
*/
class OTP538U {
public:
/**
* OTP538U constructor
*
* @param pinA Analog pin to use for the ambient temperature
* @param pinO Analog pin to use for the object temperature
* @param aref Analog reference voltage; default is 5.0 V
*/
OTP538U(int pinA, int pinO, float aref = 5.0);
/**
* OTP538U destructor
*/
~OTP538U();
/**
* Gets the ambient temperature in Celsius
*
* @return Ambient temperature
*/
float ambientTemperature();
/**
* Gets the object temperature in Celsius
*
* @return Object temperature
*/
float objectTemperature();
/**
* Sets the offset voltage
*
* The Seeed Studio wiki gives an example of calibrating the sensor
* and calculating the offset voltage to apply. Currently, the
* default value is set, but you can use the function to set one
* of your own.
*
* @param vOffset Desired offset voltage
*/
void setVoltageOffset(float vOffset) { m_offsetVoltage = vOffset; };
/**
* Sets the output resistance value
*
* The Seeed Studio wiki example uses a value of 2,000,000 in one of
* the equations used to calculate voltage. The value is the
* resistance of a resistor they use in the output stage of their
* SIG2 output. This was 'decoded' by looking at the EAGLE* files
* containing their schematics for this device.
*
* @param outResistance Value of the output resistor; default is 2M Ohm
*/
void setOutputResistence(int outResistance) {
m_vResistance = outResistance; };
/**
* Sets the reference voltage of the internal Seeed Studio voltage
* regulator on the sensor board.
*
* The Seeed Studio wiki example uses a value of 2.5 in one of the
* equations used to calculate the resistance of the ambient
* thermistor. The value is the voltage of an internal voltage
* regulator used on the sensor board. This was 'decoded' by
* looking at the EAGLE files containing their schematics for this
* device.
*
* @param vref Reference voltage of the internal sensor; default is 2.5 V
*/
void setVRef(float vref) { m_vref = vref; };
private:
float m_vref;
float m_aref;
int m_vResistance;
float m_offsetVoltage;
int m_adcResolution;
mraa_aio_context m_aioA;
mraa_aio_context m_aioO;
};
}
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