On my HTC Trinity BthReadRSSI (http://msdn2.microsoft.com/en-us/library/aa916821.aspx) is supported and returns a value in range 0-255. How can i map this value correctly to the Bluetooth specification which defines the signal strength in -127 - 128 range ! If the RSSI is within the Golden Receiver Range, HCI_Read_RSSI returns the zero. If the RSSI is below the Golden Receiver Range lower limit, HCI_Read_RSSI returns a negative value. If the RSSI is above the Golden Receiver Range upper limit, HCI_Read_RSSI returns a positive value. Is it right to convert the byte in sbyte ???

Yup looks like from the MSDN documentation that the value returned is actually a signed char.  However the text is a bit confused, e.g. mentioning "USHORT" at one place.  For complete certainty it would be better to double check, can you do some testing locally.  I don't have any device that supports that method, and I think Peter doesn't either.  Move a remote device to various distances away and see what values the method reports.  Otherwise give Microsoft developer support a call -- hopefully they will refund any charge as its a sensible question...

Hi Alan, BluetoothDeviceInfo.Rssi returns a System.Byte So the value is always positive in range 0-255. After testing with my device, i realised that to get a bluetooth specification conform value within the range -127 and 128,i had to convert the byte to sbyte. System.Convert will throw overflow exception, so i suggest to use unchecked((sbyte)bdi.Rssi) In my tests,i was getting values in range of -16 (240) to +24(24). This behaviour looks now to be OK since the hardware manufacturers are free in implementing the negative and positive scaling of the RSSI values out of the Golden Receiver Range. I have added the post in MSDN forums as well..

Thanks for your feedback. I'll look into changing the property to return a signed type. I'm still looking for a device to actually test the values for myself :-)

Peter

hi everyone,ı want to develop a project for a digital museum system.This system will send to visitor some  information for example mp3 which will describe city information.the visitor who has pocket pc shuold understand which bluetooth transmitter.because pocket pc  should take nearest bluetooth device information.In this way this is my first application on over blueetoth so Can you suggest me any information,documancation etc.

 

I didn't see your message as it was not in a new thread but at the end of an old one...

Documentation, see the user's guide (to be included in the next release) at http://www.codeplex.com/32feet/SourceControl/DirectoryView.aspx?SourcePath=%24%2f32feet%2fInTheHand.Net.Personal%2fReadme&changeSetId=28542  See the samples included in the download.

You'll want to do discovery in a loop retrying every so often, and do an OBEX push to the devices that you haven't seen before.  There could be ways to be informed when a different set of devices are discoverable -- but that's mucho advanced so do the loop for now.

I'm developping an app for Symbol MC35, and it seems to support the rssi property too!