Re: [Bluez-users] reading RSSI value with D-Bus Api

[Marcel Holtmann <marcel@holtmann.org>]

Hi Emanuele,

> reading another post here, I saw Marcel hinted to use the inquiry from
> D-Bus API to sort the devices by their RSSI so I tried a simple test
> 
> this is the part of code I'm using
> ...
> 
>  if (dbus_message_is_signal(msg, " org.bluez.Adapter",
> "RemoteDeviceFound")) {
>           printf ("Remote Device Found Signal Received\n");
>          
>              while (dbus_message_iter_get_arg_type(&iter)  !=
> DBUS_TYPE_INVALID)  { 
>                  switch (dbus_message_iter_get_arg_type(&item)) {
>                      case DBUS_TYPE_STRING:  /* first pameter
> bdaddress */
>                       .....
>        
>                      break;
>                      case DBUS_TYPE_UINT32: /* second parameter class
> of device */
>                      ........ 
>                     break;  
>                      
>                      case DBUS_TYPE_INT16: /* rssi */ 
>                          dbus_message_iter_get_basic(&args, &rssi);
>                          printf("rssi: %d\n", rssi);
>                          break;
>                      
> ......
> 
> 
> 
> Now the problem is: I can read the bdaddress and the device class
> good, but the RSSI values I get from variuous devices are negatives
> (the are in range -40 -90 usually). I read somewhere RSSI should range
> from 0 to 255 so maybe I'm doing something wrong ? api says the type
> RSSI is int16 not uint16 so I used a signed variable. 

the RSSI value is a signed int8 actually (except that D-Bus doesn't
support this type). You might confuse this with the link quality value,
but the RSSI is always signed.

Regards

Marcel



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