ianfixes / sht31

Arduino library for the SHT31 temperature and humidity sensor

SHT31

Arduino library for the SHT31 temperature and humidity sensor

Description

The SHT3x family of sensors should work up to 1 MHz I2C

This library should also work for SHT30 and SHT35 but these are not tested yet.

SENSOR	Temperature accuracy	Humidity accuracy
SHT30	~0.3	2
SHT31	~0.3	1.5
SHT35	~0.2	1.5

An elaborated library for the SHT31 sensor can be found here https://github.com/hawesg/SHT31D_Particle_Photon_ClosedCube

Interface

TODO elaborate

basic interface

• SHT31()
• bool begin(address, dataPin, clockPin)
• bool begin(address)
• bool begin(address, TwoWire *wire)
• bool read(bool fast = true) blocks 15 milliseconds + actual read + math
• bool isConnected() check senosr is reachable over I2C
• uint16_t readStatus() details see datasheet; summary below
• uint32_t lastRead() in milliSeconds since start
• void reset(bool hard = false)
• getHumidity() returns relative humidity in %
• getTemperature() returns temperature in °C

Heater interface

Do not use heater for long periods, use it for max 3 minutes to heat up and let it cool down an equal period.

• setHeatTimeout(uint8_t seconds)
• heatOn()
• heatOff()
• bool heatUp() is the sensor still heating up? // TODO isHeating() better.

Async interface

• requestData()
• bool dataReady()
• bool readData(bool fast = true)

Status fields

TODO elaborate - table

  // bit - description
  // ==================
  // 15 Alert pending status
  //    '0': no pending alerts
  //    '1': at least one pending alert - default
  // 14 Reserved ‘0’
  // 13 Heater status
  //    '0’ : Heater OFF - default
  //    '1’ : Heater ON
  // 12 Reserved '0’
  // 11 Humidity tracking alert
  //    '0’ : no alert - default
  //    '1’ : alert
  // 10 Temp tracking alert
  //    '0’ : no alert - default
  //    '1’ : alert
  // 9:5 Reserved '00000’
  // 4 System reset detected
  //    '0': no reset since last ‘clear status register’ command
  //    '1': reset detected (hard or soft reset command or supply fail) - default
  // 3:2 Reserved ‘00’
  // 1 Command status
  //    '0': last cmd executed successfully
  //    '1': last cmd not processed. Invalid or failed checksum
  // 0 Write data checksum status
  //    '0': checksum of last write correct
  //    '1': checksum of last write transfer failed

Operation

See examples