hts221.js

var i2c = require('i2c-bus');

var HTS221_ADDRESS_W      = 0x5E;
var HTS221_ADDRESS_R      = 0x5F;
var HTS221_ID             = 0xBC;

var HTS221_WHO_AM_I       = 0x0F;
var HTS221_AV_CONF        = 0x10;
var HTS221_CTRL1          = 0x20;
var HTS221_CTRL2          = 0x21;
var HTS221_CTRL3          = 0x22;
var HTS221_STATUS         = 0x27;
var HTS221_HUMIDITY_OUT_L = 0x28;
var HTS221_HUMIDITY_OUT_H = 0x29;
var HTS221_TEMP_OUT_L     = 0x2A;
var HTS221_TEMP_OUT_H     = 0x2B;
var HTS221_H0_H_2         = 0x30;
var HTS221_H1_H_2         = 0x31;
var HTS221_T0_C_8         = 0x32;
var HTS221_T1_C_8         = 0x33;
var HTS221_T1_T0          = 0x35;
var HTS221_H0_T0_OUT      = 0x36;
var HTS221_H1_T0_OUT      = 0x3A;
var HTS221_T0_OUT         = 0x3C;
var HTS221_T1_OUT         = 0x3E;


var T1_T0 = 0, T0_C_8 = 0, T0 = 0, T1_C_8 = 0, T1 = 0, T0_OUT = 0, T1_OUT = 0;
var H0_H_2 = 0, H1_H_2 = 0, H0 = 0, H1 = 0, H0_T0_OUT = 0, H1_T0_OUT = 0;

var temperature_m = 0, temperature_c = 0, humidity_m = 0, humidity_c = 0;

var initialized = false;

function init() {

  initialized = false;

  var i2c1 = i2c.openSync(1);

  // Calibrate it.
  i2c1.writeByteSync(HTS221_ADDRESS_R, HTS221_CTRL1, 0x87);
  i2c1.writeByteSync(HTS221_ADDRESS_R, HTS221_AV_CONF, 0x1B);

  // Get Calibration Data
  T1_T0 = i2c1.readByteSync(HTS221_ADDRESS_R, HTS221_T1_T0);
  T0_C_8 = ((T1_T0 & 0x03) * 256) | i2c1.readByteSync(HTS221_ADDRESS_R, HTS221_T0_C_8);
  T0 = T0_C_8 / 8;

  T1_C_8 = ((T1_T0 & 0x0C) * 64) | i2c1.readByteSync(HTS221_ADDRESS_R, HTS221_T1_C_8);
  T1 = T1_C_8 / 8;

  T0_OUT = (i2c1.readByteSync(HTS221_ADDRESS_R, HTS221_T0_OUT + 1) * 256) | i2c1.readByteSync(HTS221_ADDRESS_R, HTS221_T0_OUT);
  T1_OUT = (i2c1.readByteSync(HTS221_ADDRESS_R, HTS221_T1_OUT + 1) * 256) | i2c1.readByteSync(HTS221_ADDRESS_R, HTS221_T1_OUT);
  
  H0_H_2 = i2c1.readByteSync(HTS221_ADDRESS_R, HTS221_H0_H_2);
  H0 = H0_H_2 / 2;
  H1_H_2 = i2c1.readByteSync(HTS221_ADDRESS_R, HTS221_H1_H_2);
  H1 = H1_H_2 / 2;

  H0_T0_OUT = (i2c1.readByteSync(HTS221_ADDRESS_R, HTS221_H0_T0_OUT + 1) * 256) | i2c1.readByteSync(HTS221_ADDRESS_R, HTS221_H0_T0_OUT);
  H1_T0_OUT = (i2c1.readByteSync(HTS221_ADDRESS_R, HTS221_H1_T0_OUT + 1) * 256) | i2c1.readByteSync(HTS221_ADDRESS_R, HTS221_H1_T0_OUT);

  temperature_m = (T1 - T0) / (T1_OUT - T0_OUT);
  temperature_c = T0 - (temperature_m * T0_OUT);
  humidity_m = (H1 - H0) / (H1_T0_OUT - H0_T0_OUT);
  humidity_c = H0 - (humidity_m * H0_T0_OUT);

  i2c1.closeSync();

  initialized = true;
}

var data = {
  humidityValid: false,
  temperatureValid: false,
  temperature: 0,
  humidity: 0
};

function humidityRead() {

  if (!initialized) init();

  data.humidityValid = false;
  data.temperatureValid = false;
  data.humidity = 0;
  data.temperature = 0;

  var i2c1 = i2c.openSync(1);

  var status = i2c1.readByteSync(HTS221_ADDRESS_R, HTS221_STATUS);

  if (status & 2) {
    data.humidity = (i2c1.readByteSync(HTS221_ADDRESS_R, HTS221_HUMIDITY_OUT_H) * 256) | i2c1.readByteSync(HTS221_ADDRESS_R, HTS221_HUMIDITY_OUT_L);
    data.humidity = (data.humidity * humidity_m) + humidity_c;
    data.humidityValid = true;
  }

  if (status & 1) {
    data.temperature = (i2c1.readByteSync(HTS221_ADDRESS_R, HTS221_TEMP_OUT_H) * 256) | i2c1.readByteSync(HTS221_ADDRESS_R, HTS221_TEMP_OUT_L);
    data.temperature = (data.temperature * temperature_m) + temperature_c;
    data.temperatureValid = true;
  }

  i2c1.closeSync();

  return data;
}

module.exports.get = humidityRead;

//module.exports.get = function(cb) {
//  console.log(humidityRead());
//  getTemperatureFromHumidity();
//};

var HTS221_ADDR = 0x5F;

var CMD_HUMID_HIGH = 0x29;
var CMD_HUMID_LOW = 0x28;

var CMD_T_OUT_L = 0x2A;
var CMD_T_OUT_H = 0x2B;

var CMD_T0_DEGC_X8 = 0x32;
var CMD_T1_DEGC_X8 = 0x33;

var CMD_T0_T1_DEGC_H2 = 0x35;

var CMD_T0_OUT_L = 0x3C;
var CMD_T0_OUT_H = 0x3D;
var CMD_T1_OUT_L = 0x3E;
var CMD_T1_OUT_H = 0x3F;

function getTemperatureFromHumidity() {

  var T0_out, T1_out, T_out, T0_degC_x8_u16, T1_degC_x8_u16, T0_degC, T1_degC;
  var H_out;

  var i2c1 = i2c.openSync(1);

  i2c1.writeByteSync(HTS221_ADDR, 0x20, 0x87);
  i2c1.writeByteSync(HTS221_ADDR, 0x10, 0x1B);

  var T0_degC_x8 = i2c1.readByteSync(HTS221_ADDR, CMD_T0_DEGC_X8);
  var T1_degC_x8 = i2c1.readByteSync(HTS221_ADDR, CMD_T1_DEGC_X8);
  var T0_T1_DEGC_H2 = i2c1.readByteSync(HTS221_ADDR, CMD_T0_T1_DEGC_H2);

  T0_degC_x8_u16 = ((T0_T1_DEGC_H2 & 0x03) * 256) | T0_degC_x8;
  T1_degC_x8_u16 = ((T0_T1_DEGC_H2 & 0x0C) * 64) | T1_degC_x8;

  T0_degC = T0_degC_x8_u16 / 8;
  T1_degC = T1_degC_x8_u16 / 8;

  T0_out = (i2c1.readByteSync(HTS221_ADDR, CMD_T0_OUT_H) * 256) | i2c1.readByteSync(HTS221_ADDR, CMD_T0_OUT_L);
  T1_out = (i2c1.readByteSync(HTS221_ADDR, CMD_T1_OUT_H) * 256) | i2c1.readByteSync(HTS221_ADDR, CMD_T1_OUT_L); 

  H_out = (i2c1.readByteSync(HTS221_ADDR, CMD_HUMID_HIGH) * 256) | i2c1.readByteSync(HTS221_ADDR, CMD_HUMID_LOW);
  T_out = (i2c1.readByteSync(HTS221_ADDR, CMD_T_OUT_H) * 256) | i2c1.readByteSync(HTS221_ADDR, CMD_T_OUT_L);

  i2c1.closeSync();

  console.log('old', T0_T1_DEGC_H2, T0_degC_x8_u16, T0_degC, T1_degC_x8_u16, T1_degC, T0_out, T1_out);
  
  var T0 = T0_degC;
  var T1 = T1_degC;
  var temperature_m = (T1 - T0) / (T1_out - T0_out);
  var temperature_c = T0 - (temperature_m * T0_out);

  var temperature = (T_out * temperature_m) + temperature_c;

  console.log(temperature);

  var part1 = T_out - T0_out;
  var part2 = T1_degC - T0_degC;
  if (part1 < 0) part1 = 65536 + part1;
  if (part2 < 0) part2 = 65536 + part2;

  var result = ((part1 * part2 * 10) / (T1_out - T0_out)) + (T0_degC * 10);

  console.log(result);

  return result;

}



//module.exports.get = function(cb) {
//  getTemperatureFromHumidity();
//};

module.exports.temp = function(cb) {
  console.log(__dirname + '/sense-hat.py');
  require('python-shell').run(__dirname + '/sense-hat.py', function(err, results) {
    if (err) throw err; //return cb(err, null);
    return cb(err, JSON.parse(results[0]));
  });

/*
  var i2c1 = i2c.openSync(1);
  var high = i2c1.readByteSync(HTS221_ADDR, CMD_TEMP_HIGH);
  var low = i2c1.readByteSync(HTS221_ADDR, CMD_TEMP_LOW);
  var rawTemp = i2c1.readByteSync(HTS221_ADDR, CMD_TEMP_HIGH) * 256 | i2c1.readByteSync(HTS221_ADDR, CMD_TEMP_LOW);
  console.log(rawTemp, high, low);
  i2c1.closeSync();
*/
};



// var PythonShell = require('python-shell');
//module.exports = {
//  get: function(cb) {
//    //console.log('Hello', require('path').dirname('sense-hat.py'));
//    //console.log('Help', require('path').relative('.', 'require
//    require('fs').stat('./sense-hat.py', function(err, stat) { console.log('exists', err, stat); });
////    PythonShell.run('sense-hat.py', function(err, results) {
////      if (err) return cb(err, null);
////      return cb(err, JSON.parse(results[0]));
////    });
//  }
//};