ojousima.ruuvi_endpoints.ts/src/ruuvi_endpoint_3.ts

Experiments with RuuviTags and TS

import { RuuviTagBroadcast } from './ruuvitagbroadcast';

const humidityStart = 1;
const humidityEnd = humidityStart + 1;
const temperatureStart = humidityEnd;
const temperatureEnd = temperatureStart + 2;
const pressureStart = temperatureEnd;
const pressureEnd = pressureStart + 2;
const accelerationXStart = pressureEnd;
const accelerationXEnd = accelerationXStart + 2;
const accelerationYStart = accelerationXEnd;
const accelerationYEnd = accelerationYStart + 2;
const accelerationZStart = accelerationYEnd;
const accelerationZEnd = accelerationZStart + 2;
const batteryStart = accelerationZEnd;
const batteryEnd = batteryStart + 2;

export const df3parser = (data: Uint8Array): RuuviTagBroadcast => {
  const robject: RuuviTagBroadcast = new RuuviTagBroadcast();
  if (3 !== data[0]) {
    throw new Error('Not DF3 data');
  }

  let humidity = data[humidityStart];
  humidity /= 2; // scale
  robject.humidityRh = humidity;

  const temperatureBytes = data.slice(temperatureStart, temperatureEnd);
  let temperature = temperatureBytes[0]; // Full degrees
  temperature += temperatureBytes[1] / 100.0; // Decimals
  if (temperature > 128) {
    // Ruuvi format, sign bit + value
    temperature = temperature - 128;
    temperature = 0 - temperature;
  }
  robject.temperatureC = temperature;

  const pressureBytes = data.slice(pressureStart, pressureEnd); // uint16_t pascals
  let pressure = pressureBytes[0] * 256 + pressureBytes[1];
  pressure += 50000; // Ruuvi format
  robject.pressurePa = pressure;

  let accelerationBytes = data.slice(accelerationXStart, accelerationXEnd); // milli-g
  let accelerationX = accelerationBytes[0] * 256 + accelerationBytes[1];
  if (accelerationX > 32767) {
    accelerationX -= 65536;
  } // two's complement

  accelerationBytes = data.slice(accelerationYStart, accelerationYEnd); // milli-g
  let accelerationY = accelerationBytes[0] * 256 + accelerationBytes[1];
  if (accelerationY > 32767) {
    accelerationY -= 65536;
  } // two's complement

  accelerationBytes = data.slice(accelerationZStart, accelerationZEnd); // milli-g
  let accelerationZ = accelerationBytes[0] * 256 + accelerationBytes[1];
  if (accelerationZ > 32767) {
    accelerationZ -= 65536;
  } // two's complement

  robject.accelerationXG = accelerationX / 1000.0;
  robject.accelerationYG = accelerationY / 1000.0;
  robject.accelerationZG = accelerationZ / 1000.0;

  const batteryBytes = data.slice(batteryStart, batteryEnd); // milli volts
  const battery = batteryBytes[0] * 256 + batteryBytes[1];
  robject.batteryVoltageV = battery / 1000.0;
  robject.dataFormat = 3;

  return robject;
};