utils_temp.h

Go to the documentation of this file.

 
#ifndef UTILS_TEMP_H
#define UTILS_TEMP_H
 
#include <Arduino.h>
 
#include "constants.h"
 
#ifdef TEMP_ENABLED
inline constexpr bool TEMP_SENSOR_PRESENT{ true }; 
#include <OneWire.h>                               // for temperature sensing
#else
inline constexpr bool TEMP_SENSOR_PRESENT{ false }; 
#endif
 
struct DeviceAddress
{
  uint8_t addr[8]; 
};
 
template< uint8_t N >
class TemperatureSensing
{
  using ScratchPad = uint8_t[9];
 
public:
  constexpr TemperatureSensing() = delete;
 
  constexpr TemperatureSensing(uint8_t pin, const DeviceAddress (&ref)[N])
    : sensorPin{ pin }, sensorAddrs(ref)
  {
  }
 
  void requestTemperatures()
  {
#ifdef TEMP_ENABLED
    oneWire.reset();
    oneWire.skip();
    oneWire.write(CONVERT_TEMPERATURE);
#endif
  }
 
  void initTemperatureSensors()
  {
#ifdef TEMP_ENABLED
    oneWire.begin(sensorPin);
    requestTemperatures();
#endif
  }
 
  constexpr auto get_size() const
  {
    return N;
  }
 
  constexpr auto get_pin() const
  {
    return sensorPin;
  }
 
  int16_t readTemperature(const uint8_t idx)
  {
    static ScratchPad buf;
 
#ifdef TEMP_ENABLED
    if (!oneWire.reset())
    {
      return DEVICE_DISCONNECTED_RAW;
    }
    oneWire.select(sensorAddrs[idx].addr);
    oneWire.write(READ_SCRATCHPAD);
 
    for (auto &buf_elem : buf)
    {
      buf_elem = oneWire.read();
    }
 
    if (!oneWire.reset())
    {
      return DEVICE_DISCONNECTED_RAW;
    }
    if (oneWire.crc8(buf, 8) != buf[8])
    {
      return DEVICE_DISCONNECTED_RAW;
    }
#endif
 
    // result is temperature x16, multiply by 6.25 to convert to temperature x100
    int16_t result = (buf[1] << 8) | buf[0];
    result = (result * 6) + (result >> 2);
    if (result <= TEMP_RANGE_LOW || result >= TEMP_RANGE_HIGH)
    {
      return OUTOFRANGE_TEMPERATURE;  // return value ('Out of range')
    }
 
    return result;
  }
 
private:
  const uint8_t sensorPin; 
  const DeviceAddress sensorAddrs[N]; 
#ifdef TEMP_ENABLED
  static inline OneWire oneWire; 
#endif
};
 
#endif  // UTILS_TEMP_H