Smart Bluetooth Forum Discussions
Hello,
we are interested in using BCM20702 based dongle from http://plugable.com/products/usb-bt4le and Broadcom SDK http://www.broadcom.com/support/bluetooth/sdk.php for development.
Because, in the SDK I do not see the API for some profiles such HFP, MAP, PBAP, I would like to ask you(I see that many people are using your dongle for the development, so I think you have already some experience with the questions of the following types):
Is there any way how to use Broadcom's HFP profile programmatically please?
For example how to "send a call to the remote device" using the HFP profile programmatically, any API provided by Broadcomm SDK or WICED-Smart-SDK? Or should this be executed on the audio driver level, but how? Any hint is truely appeciated!
Thank you a lot.
Show LessI have downloaded the 'WICED Sense Android Source(v1.06)' and tried to load this as a project in Eclipse so that I can modify and build my own version. But while performing build operation, I got the following error.
Errors occurred during the build.
Errors running builder 'Java Builder' on project 'WSense'.
java.lang.NullPointerException
Can anyone guide me in rectifying the error.
Show LessIch hab das Wiced smart am PC und bin über das Laptop-bluetooth zu dem Modul verbunden.
Leider zeigt er mir keine Dienste an. Ich wollte eigentlich über eine vituelle serielle Schittstelle mit nem Terminal komunizieren.
Ich hab das Modul erst seit heute und werd nicht wirklich schlau daraus, da es wie mir scheint nicht wie die standard BTteile ist, die meistens über AT Commands eingestellt werden. Oder lieg ich da falsch? Oder gibt es ein Äquivalent zu AT commands beim BCM?
Wie schaffe ich es, dass mir am Laptop beim erkennen des Moduls der Treiber für die virtuelle serielle Schnittstelle installiert wird?
Bei den Panasonicmodulen sowie bei Blueradio schickt man dem PC- Modul einfach das AT-commad "register local service" und am Laptop installiert sich der Treiber und der com port dienst ist verfügbar.
Ich habe versucht verschiedene Profile übers sdk in das Wiced Smart zu laden, jedoch wurde der Treiber am Läppi nicht aktiviert
Wie geht das beim Wiced Smart? Oder stimmt was bei mir nicht? Oder ist mein ganzer Ansatz falsch? Oder hab ich Lebkuchen im USB Slot. Vielen Dank für die Hilfe.
Show LessThe trace output comes out of the HCI UART right? It always comes out of the HCI UART irrespective of what's attached to those pins? Is there a way to turn off all trace output or disable the HCI UART so the pins tri-state? (after boot up when the 20737 checks to see if it's meant to go into programming mode.)
Show LessHi all,
Can someone point me to the right direction on how to write an peripheral app for proximity triggered event using same device (phone, laptop).
I know there is Proximity Profile, but I don't know how to setup the dev kit so peripheral and central devices automatically paired.
Show LessThinking about if RSSI (on smartphone App) can be used in order to estimate the distance between WICEDSense and smartphone results in these thoughts:
Distance and RSSI
There is a formula to convert RSSI (a -dBm value) into a "rough" distance:
RSSI = - ( 10 * n * log10(d) + RSSIdo )
d = d0 * 10EXP ( ( RSSIdo - RSSI ) / ( 10 * n ) )
- Even without to know the Tx power (no need to get Tx level via ADV messages from BLE device) - you can calibrate the system:
If you can measure (with your App, e.g. in Android Java code as readRemoteRssi() ) the RSSIdo - which is the RSSI value in 1 m distance - you can try to estimate the distance. - d = distance
do = calibration distance, e.g. 1 m away
RSSIdo = the RSSI level on do, RSSI with 1 m distance
RSSI = any RSSI value measured
n = "Pass Loss Index", "Signal Propagation Constant"
10EXP means here: the power to base 10 with this exponent
The problem is the "Propagation Model", the value of n.
Assuming a perfect line of sight, no echos, a Gaussian RF channel, n can be 2 ...3 (will never be the case).
But under real conditions: n is not constant and depends on situations (indoor, multi-path-reception, interference ...). I think n should be at least 3.5 and can go up to 6.
So, measuring distance with RSSI will not be very accurate. Especially the more far away the device is (and RSSI is very low), the noise, fading effects, echos and reflections become more effective. Therefore there are ideas for adaptive approaches. For instance:
You could increase n if you realize the RSSI level is small (weak). Or: you could measure and calibrate for the current situation, e.g. for using just in the same indoor location all the time. Or changing between outdoor and indoor and user has to "inform" on smartphone where we are so that we use different values for n.
And: RSSI has a huge variation (spatial effects), assuming to see +/-10 ... 20 dBm difference between two measurements can be common. So, a simple average might not be good enough, a bit more math seems to be needed ("find the best matching graph", build the median ...)
Attached some nice papers found dealing with this topic.
Show LessDoes anybody know how to get the RSSI (and the RF Tx power as reference) on Android App?
Instead to see just on connection and device selection - I want to display RSSI all the time.
And I would need also the info what the current RF Tx power is (as reference for "link loss").
Do I need a new service on FW to send this RF Tx power? (not from source code, really send from device to App)
As I understand, the RSSI itself should be possible without a FW change. But what is the Android code to get it?
Thank you for any guidance or hints.
Show LessHi,
Is there timeout check after call of blecm_CreateConnection to one device which is not reachable?
If yes, any callback will be invoked? And what't the timeout value? 10 s?
Show LessWICED-Smart SDK: 2.1.1
Use the IDE to download the image, failed, the following content in download.log, what error can bring this content?
BluetoolDownloadMinidriver failed!
Show LessAbove pictures in oscilloscope screenshort of BCM20737TAG SPI, spi_pressure_sensor application.
D3 is CS
D2 is CLK.
D1 is MOSI
D0 is MISO
I have a question that why CLK juse have five rising edge? I think it should be 8-bit transfer.
Show Less