Nespresso coffee machine BLE experiments (get AUTH_KEY with Android BT HCI log and Wireshark)

nespresso.js

const noble = require('noble');
const SERVICE_UUID = '06aa1910f22a11e39daa0002a5d5c51b';
const TEMPERATURE = {low: '01', medium: '00', high: '02'};
const VOLUME = {ristretto: '00', espresso: '01', lungo: '02', americano: '04', hotwater: '05', recipe: '07'};
let brew_cmd = (vol, t)=>`0305070400000000${TEMPERATURE[t]}${VOLUME[vol]}`;

let process_char = char=>{
  if (char.uuid=='06aa3a41f22a11e39daa0002a5d5c51b')
  {
    char.write(Buffer.from(AUTH_KEY, 'hex'));
    console.log('Auth done');
  }
  else if (char.uuid=='06aa3a42f22a11e39daa0002a5d5c51b')
  {
    char.write(Buffer.from(brew_cmd('lungo', 'high'), 'hex'));
    console.log('Brew done');
  }
};

console.log('Waiting for device');

let discovered = 0;
noble.on('discover', machine=>{
  if (discovered++)
    return;
  console.log(`Coffee machine found: ${machine.advertisement.localName} (${machine.address}), id=${machine.id}`);
  noble.stopScanning();
  machine.connect(err=>{
    console.log('Connected')
    // service/char discovery not needed, just write to appropriate characteristics
    machine.discoverServices([], (err, services)=>
      services.forEach(srv=>srv.discoverCharacteristics([], (err, chars)=>chars.forEach(char=>process_char(char)))))
  });
});

noble.on('stateChange', state=>{
  if (state=='poweredOn')
    return void noble.startScanning([SERVICE_UUID], true);
  noble.stopScanning();
});