rssi

Short version: In my tests with Android 5.0 Lollipop I have noticed android.bluetooth.le.BluetoothLeScanner detects BLE devices less frequently than Android 4.4 KitKat. Why is this and is there an alternative? Long version: I am developing an Android application, specifically for the Nexus 7 tablet, that focuses on detecting Bluetooth Low Energy (BLE) devices. The app is mainly interested in the RSSI value of the beacons, to determine their proximity to the tablet. This means I won't need to connect to the BLE device, since the RSSI value is passed to the scan callback when the device is

I'm writing an android application that collects cell signal strengths. I am having trouble getting the "current" cell signal strength, but I don't have any problem getting the "neighboring" cell signal strengths. To get the current cell signal strength, I created a PhoneStateListener and implemented the onSignalStrengthChanged callback. It works, but not very well. It seems like the signal strength hardly ever changes, and resolution jumps to only a few numbers. I would accept the answer that the resolution of the signal strength hardware is coarse, but when I use the TelephonyManager's

My application needs to constantly get RSSI value of a bluetooth device to make some distance-rssi approximation, without connecting . However, callback method of the BluetoothAdapter gets the RSSI only once when the device scanned. // Device scan callback private BluetoothAdapter.LeScanCallback leScanCallback = new BluetoothAdapter.LeScanCallback() { @Override public void onLeScan(final BluetoothDevice device, final int rssi, byte[] scanRecord) { runOnUiThread(new Runnable() { public void run() { ... } }); } }; As a solution, I created two Runnable objects. One is for starting, other is for

蓝牙BLE最大的特点就是成本和功耗的降低，且适用于实时性要求比较高的领域。除了在传输速率上要慢一些之外，还支持1对多广播，通过Mesh技术，还能做到多对多; 蓝牙历史上的四大创新应用 :音频传输、低功耗数据传输、定位、设备网络. 蓝牙4.2：有一定得定位功能 蓝牙5.0：定位精度小于1米，精度高于V4.2；速率*2；距离达300米；功耗更低 蓝牙5.1： 对通用属性配置文件（GATT）缓存的改进，实现更快，更节能的连接 通过 多天线和接收RSSI强度测方向 ，精度达到 厘米 级别，但是在2.4G同频干扰情况下是否能达到还未知；同时增加了 蓝牙基站的复杂度和硬件成本。应用场景： 寻向(direction finding)功能」，配合蓝牙近接(proximity)技术可得到 靠近感知 技术（发声指向） ，即可让设备更容易被侦测发现（丢失找回）/监控被监控物得移动/触发限制进入区域报警/图书馆感兴趣书得指向/停车场车辆得引导等。 蓝牙定位原理： 　　基于RSSI原理，分为终端定位（相对）：（如智能手机通过识别不同蓝牙终端发来得信号RSSI（至少3点））；网络侧定位（终端在进入蓝牙网关（参考定位点）范围内时广播信息，蓝牙网关收到（n,RSSI)并将自己得坐标然后传送给服务器后台，服务器后台根据各RSSI和定位算法得到定位）。应用：火灾被困人员定位系统