obniz/parts/TemperatureSensor/i2c/SHT31/index.js

obniz sdk for javascript

class SHT31 {
  constructor() {
    this.requiredKeys = ['adr', 'addressmode'];
    this.keys = [
      'vcc',
      'sda',
      'scl',
      'gnd',
      'adr',
      'addressmode',
      'i2c',
      'pull',
    ];

    this.ioKeys = ['vcc', 'sda', 'scl', 'gnd', 'adr'];
    this.commands = {};
    this.commands.softReset = [0x30, 0xa2];
    this.commands.highRepeatStreach = [0x2c, 0x06];
    this.commands.middleRepeatStreach = [0x2c, 0x0d];
    this.commands.lowRepeatStreach = [0x2c, 0x10];
    this.commands.highRepeat = [0x24, 0x00];
    this.commands.mediumRepeat = [0x24, 0x0b];
    this.commands.lowRepeat = [0x24, 0x16];

    this.waitTime = {};
    this.waitTime.wakeup = 1;
    this.waitTime.softReset = 1;
    this.waitTime.lowRepeat = 4;
    this.waitTime.mediumRepeat = 6;
    this.waitTime.highRepeat = 15;

    //not tested
    this.commands.readStatus = [0xf3, 0x2d];
  }

  static info() {
    return {
      name: 'SHT31',
    };
  }

  wired(obniz) {
    this.obniz = obniz;
    this.obniz.setVccGnd(this.params.vcc, this.params.gnd, '5v');
    this.io_adr = obniz.getIO(this.params.adr);

    if (this.params.addressmode === 4) {
      this.io_adr.output(false);
      this.address = 0x44;
    } else if (this.params.addressmode === 5) {
      this.io_adr.pull(null);
      this.address = 0x45;
    }

    this.params.clock = this.params.clock || 100 * 1000; //for i2c
    this.params.mode = this.params.mode || 'master'; //for i2c
    this.params.pull = this.params.pull || '5v'; //for i2c
    this.i2c = obniz.getI2CWithConfig(this.params);
    obniz.i2c0.write(this.address, this.commands.softReset);
  }

  async getData() {
    this.i2c.write(this.address, this.commands.highRepeat);
    await this.obniz.wait(this.waitTime.highRepeat);
    return await this.i2c.readWait(this.address, 6);
  }

  async getTempWait() {
    return (await this.getAllWait()).temperature;
  }

  async getHumdWait() {
    return (await this.getAllWait()).humidity;
  }

  async getAllWait() {
    let ret = await this.getData();

    let tempBin = ret[0] * 256 + ret[1];
    let temperature = -45 + 175 * (tempBin / (65536 - 1));

    let humdBin = ret[3] * 256 + ret[4];
    let humidity = 100 * (humdBin / (65536 - 1));
    return { temperature, humidity };
  }
}

if (typeof module === 'object') {
  module.exports = SHT31;
}