BLE 扫描在发现少数设备后停止

Question

在运行之后第一次 以下代码来自我的 Raspberry Pi 4 上给出的 here 示例之一，它工作正常并找到许多设备。但是当我重新运行时扫描功能坏了，只找到几个设备:

noble.on('stateChange', function(state) {
  if (state === 'poweredOn') {
    noble.startScanning();
  } else {
    noble.stopScanning();
  }
});

noble.on('discover', function(peripheral) {
  console.log('peripheral discovered (' + peripheral.id +
              ' with address <' + peripheral.address +  ', ' + peripheral.addressType + '>,' +
              ' connectable ' + peripheral.connectable + ',' +
              ' RSSI ' + peripheral.rssi + ':');
  console.log('\thello my local name is:');
  console.log('\t\t' + peripheral.advertisement.localName);
  console.log('\tcan I interest you in any of the following advertised services:');
  console.log('\t\t' + JSON.stringify(peripheral.advertisement.serviceUuids));

  var serviceData = peripheral.advertisement.serviceData;
  if (serviceData && serviceData.length) {
    console.log('\there is my service data:');
    for (var i in serviceData) {
      console.log('\t\t' + JSON.stringify(serviceData[i].uuid) + ': ' + JSON.stringify(serviceData[i].data.toString('hex')));
    }
  }
  if (peripheral.advertisement.manufacturerData) {
    console.log('\there is my manufacturer data:');
    console.log('\t\t' + JSON.stringify(peripheral.advertisement.manufacturerData.toString('hex')));
  }
  if (peripheral.advertisement.txPowerLevel !== undefined) {
    console.log('\tmy TX power level is:');
    console.log('\t\t' + peripheral.advertisement.txPowerLevel);
  }

  console.log();
});

如果我重置设备，问题就会消失。如果我通过 bluetoothctl 然后 scan on 扫描，则完全没有问题。我可以根据需要扫描和关闭。所以我的猜测是这个问题与 noble.js

有关

这是 sudo btmon 扫描停止的输出。

这是 scan on 挂起的图像。

BlueZ 版本为 5.50。

Answer 1

问题是当 duplicates 设置为 false 时，我只是在没有停止扫描的情况下退出脚本。因此，当我重新运行时，只发现了一些新设备。

BLE 扫描在发现少数设备后停止

BLE Scan stops after discovering few devices

javascript

bluetooth

bluetooth-lowenergy

bluez

raspberry-pi4