SHT31 Library using i2c-bus for Node.js

Read temperature and humidity from the SHT31 sensor on the Raspberry Pi using i2c through the i2c-bus package.

Credit where due

• Inspired by a python library https://github.com/jaques/sht21_python
• Initially a fork of Alwin Arrasyid’s well written sht31-node package.
  I wanted to use i2c-bus instead of i2c. This code is very similar as a result, and is almost a drop in replacement.
• The data sheet made this possible

Requirements

• A raspberry Pi
• Node v6 or newer (tested on 6.11.4 and 9.1.0)
• I²C must be enabled.
• SHT31 or SHT35 sensor Adafruit

Dependancies

• i2c-bus

Usage Example

const SHT31 = require('raspi-node-sht31');
const sht31 = new SHT31();
// Read the temp, after it resolves turn on the sensor heater and get the status, then turn off the heater after 10 seconds and show the status.
sht31.readSensorData().then(console.log, console.log).finally( () => {
  setTimeout(function(){
    sht31.getStatus().then(console.log, console.log);
  }, 3000)
  sht31.enableHeater(10000).then( () => sht31.getStatus() ).then(console.log, console.log);
});

A More Typical Usage

// Include the library
const SHT31 = require('raspi-node-sht31');
// Instantiate the class
const sht31 = new SHT31(); // Paramteres unecessary when using a B+, A+, Zero, Zero W, Pi 2, or Pi 3 (basically an orignal Pi uses 0 and must be set: new SHT31(0x44, 0))
// Read temperature and display in console in F with Relative humidity
sht31.readSensorData().then((data) => {
  // I love arrow notation functions inside of promises.
  // Temp in Fahrenheit -- If you get floating point rouding errors, multiply by ten before rouding, divide by 10 after.
  const temp = Math.round(data.temperature * 1.8 + 32);
  const humidity = Math.round(data.humidity);
  console.log(`The temperature is: ${temp} degress F\nThe Humidity is: ${humidity}%`); // Template strings are great.
}).catch(console.log);

Notes

Issuing multiple commands before while one is unresolved will result in an error.