如何从 android 中的 BLE 设备获取实际值？

Question

在获得血压服务的所有特征后，我无法获得值（来自血压测量机的收缩压、舒张压和脉搏） (uuid: 00002a35-0000-1000-8000-00805f9b34fb) 而且我没有理解所有这些特征和描述符的要点。所以请任何人帮助我解决 BLE 设备中的这个问题。

Answer 1

你问的太笼统了。可能您需要从这个 link.

了解 Android BLE 流程

See this tutorial on BLE

一个GATT数据库实现一个或多个profiles(Heart Rate, Audio etc)，每个配置文件由一个或多个services组成，每个服务由一个或多个characteristics.

只是为了让您一瞥，characteristics 是属性，您可以在其中定义要用于读取或写入的属性。

descriptors 是您将数据写入 enable/send 数据的对象。

UUID您用于发送和接收数据的内容在客户端和服务器之间应该相同。

Answer 2

尝试解析扫描记录，你可能会在那里找到一些信息

Kotlin 代码

    enum class EBLE {

    EBLE_ZERO, // Zero element
    EBLE_FLAGS, //«Flags»   Bluetooth Core Specification:
    EBLE_16BitUUIDInc, //«Incomplete List of 16-bit Service Class UUIDs»    Bluetooth Core Specification:
    EBLE_16BitUUIDCom, //«Complete List of 16-bit Service Class UUIDs»  Bluetooth Core Specification:
    EBLE_32BitUUIDInc,//«Incomplete List of 32-bit Service Class UUIDs» Bluetooth Core Specification:
    EBLE_32BitUUIDCom,//«Complete List of 32-bit Service Class UUIDs»   Bluetooth Core Specification:
    EBLE_128BitUUIDInc,//«Incomplete List of 128-bit Service Class UUIDs»   Bluetooth Core Specification:
    EBLE_128BitUUIDCom,//«Complete List of 128-bit Service Class UUIDs» Bluetooth Core Specification:
    EBLE_SHORTNAME,//«Shortened Local Name» Bluetooth Core Specification:
    EBLE_LOCALNAME,//«Complete Local Name»  Bluetooth Core Specification:
    EBLE_TXPOWERLEVEL,//«Tx Power Level»    Bluetooth Core Specification:
    EBLE_DEVICECLASS,//«Class of Device»    Bluetooth Core Specification:
    EBLE_SIMPLEPAIRHASH,//«Simple Pairing Hash C»   Bluetooth Core Specification:«Simple Pairing Hash C-192»   Core Specification Supplement, Part A, section 1.6
    EBLE_SIMPLEPAIRRAND,//«Simple Pairing Randomizer R» Bluetooth Core Specification:«Simple Pairing Randomizer R-192» Core Specification Supplement, Part A, section 1.6
    EBLE_DEVICEID,//«Device ID» Device ID Profile v1.3 or later,«Security Manager TK Value» Bluetooth Core Specification:
    EBLE_SECURITYMANAGER,//«Security Manager Out of Band Flags» Bluetooth Core Specification:
    EBLE_SLAVEINTERVALRA,//«Slave Connection Interval Range»    Bluetooth Core Specification:
    EBLE_16BitSSUUID,//«List of 16-bit Service Solicitation UUIDs»  Bluetooth Core Specification:
    EBLE_128BitSSUUID, //«List of 128-bit Service Solicitation UUIDs»   Bluetooth Core Specification:
    EBLE_SERVICEDATA,//«Service Data»   Bluetooth Core Specification:«Service Data - 16-bit UUID»  Core Specification Supplement, Part A, section 1.11
    EBLE_PTADDRESS,//«Public Target Address»    Bluetooth Core Specification:
    EBLE_RTADDRESS,//«Random Target Address»    Bluetooth Core Specification:
    EBLE_APPEARANCE,//«Appearance»  Bluetooth Core Specification:
    EBLE_DEVADDRESS,//«LE Bluetooth Device Address»    Core Specification Supplement, Part A, section 1.16
    EBLE_LEROLE,//«LE Role»    Core Specification Supplement, Part A, section 1.17
    EBLE_PAIRINGHASH,//«Simple Pairing Hash C-256» Core Specification Supplement, Part A, section 1.6
    EBLE_PAIRINGRAND,//«Simple Pairing Randomizer R-256»   Core Specification Supplement, Part A, section 1.6
    EBLE_32BitSSUUID,//«List of 32-bit Service Solicitation UUIDs» Core Specification Supplement, Part A, section 1.10
    EBLE_32BitSERDATA,//«Service Data - 32-bit UUID»   Core Specification Supplement, Part A, section 1.11
    EBLE_128BitSERDATA,//«Service Data - 128-bit UUID» Core Specification Supplement, Part A, section 1.11
    EBLE_SECCONCONF,//«LE Secure Connections Confirmation Value»  Core Specification Supplement Part A, Section 1.6
    EBLE_SECCONRAND,//«LE Secure Connections Random Value»   Core Specification Supplement Part A, Section 1.6
    EBLE_3DINFDATA, //«3D Information Data»   3D Synchronization Profile, v1.0 or later
    EBLE_MANDATA; //«Manufacturer Specific Data»    Bluetooth Core Specification:

    companion object {
        private val map = EBLE.values()
        fun fromInt(type: Int) = if (type > 0) map[type] else EBLE_MANDATA

        fun getDistance(rssi: Int, txPower: Int) = {
            /*
             * RSSI = TxPower - 10 * n * lg(d)
             * n = 2 (in free space)
             *
             * d = 10 ^ ((TxPower - RSSI) / (10 * n))
            */

             Math.pow(10.0, (txPower.toDouble() - rssi) / (10 * 2))
        }
        /*
     BLE Scan record parsing
    */
    fun ParseRecord(scanRecord: ByteArray): Map<EBLE, ByteArray> {
        val ret = HashMap<EBLE, ByteArray>()
        var index = 0
        while (index < scanRecord.size) {
            val length = scanRecord[index++].toInt()
            //Zero value indicates that we are done with the record now
            if (length == 0) break

            val type = scanRecord[index].toInt()
            //if the type is zero, then we are pass the significant section of the data,
            // and we are thud done
            if (type == 0) break

            Arrays.copyOfRange(scanRecord, index + 1, index + length)?.let {
                ret[EBLE.fromInt(type)] = it //HexUtil.formatHexString(it)
            }

            index += length
        }

        return ret
    }
    }
}

如何从 android 中的 BLE 设备获取实际值？

How to get actual values from BLE device in android?

android

bluetooth-lowenergy

gatt

bluetooth-gatt