3 Replies Latest reply on Mar 30, 2015 11:38 PM by BoonT_56

    How to get the TxPower in android

      Hi, all, I have already known how to get the rssi in android,

      But I don't know how to get the current TX Power in android.

      In iBeacon, TxPower locates in the device scanning data,

      But when I checked it, it doesn't match the ibeacom data format. I used Wiced Sence (BCM20737s).

       

      So,  !How can I get the TxPower data in android. Who can tell me, thanks a lot.

        • 1. Re: How to get the TxPower in android
          BoonT_56

          Are you saying you cannot extract the Tx-power information broadcasted by your ibeacon?

           

          Subject to the availability of a valid MFi license, did you have a chance to walk through the ibeacon apps within the SDK?

          • 2. Re: How to get the TxPower in android

            Thank you for the reply.

            I checked the code in SDK.

            There is a function wiced_sense_create in wiced_sense.c, It seems like the firmware sample code.

            the code said:

               BLE_ADV_FIELD adv[3];

                // flags

                adv[0].len  = 1 + 1;
                adv[0].val  = ADV_FLAGS;

                adv[0].data[0]  = LE_LIMITED_DISCOVERABLE | BR_EDR_NOT_SUPPORTED;

            ......

                // Set TX power when connected/advertising to 0 dBm.

            blecm_setTxPowerInADV(0);
            blecm_setTxPowerInConnection(0);

             

            The comments said it set the txpower to 0dBm, But it seems too large, I got the rssi from android sdk just -50 ~ -70.

            Is it the real TxPower value in broadcast packets? if not, what it is?

            • 3. Re: How to get the TxPower in android
              BoonT_56

              The upper limit of the tx power of class 2 device is 4dBm. After taking into account of product variation and safety margins to pass bqb, the tx power is often set to between 0 and 2.5dBm. If this is a beacon, then 0dBm could be chosen, to enhance battery life. This value is a MAX value and the actual tx power output is subject to the relative distance between the transmitter and receiver. For example, for the chip to blast out 0dBm, the Tx and Rx could be 10m apart, or furthur. For the very same reason, we have the concept of RSSI to determine just so enough of tx power to maintain a BER of 0.1%.

               

              I believe my Korea colleague will be getting in touch with you shortly.