Hello all:

I am working on a simple system of Telos B Motes to do some distance ranging experiments. I realize that this subject has been beat dead on this board, but I am stuck and would appreciate any insight.

I have several motes programmed with CntToRfm. No problems there. I can install TOSBase on a Base mote and see that those are in fact transmitting a counter over the radio.

I am working on a modification to the Base Mote that extracts the RSSI information and replaces the payload (ie the counter data) with the RSSI for that packet. I know that the command to get this information is 

Msg->strength;

However, replacing the payload is where I am stuck. I am having difficulties understanding NesC enough to make this happen. I tried to use the TOSBase app in $TOSHOME/apps/TOSBase/  without any luck. I searched the archives of this board and came across a guy who modified the TOSBase located in $TOSHOME/apps/TransparentBase/ as such

1> event TOS_MsgPtr RadioReceive.receive(TOS_MsgPtr Msg) {
2>     TOS_MsgPtr pBuf;
3>      dbg(DBG_USR1, "TOSBase received radio packet.\n");
4>     if (Msg->crc) {
5>      /* Filter out messages by group id */
6>      if (Msg->group != TOS_AM_GROUP)
7>        return Msg;
8>      atomic {
9>  pBuf = gRxBufPoolTbl[gRxHeadIndex];
10>  if (pBuf->length == 0) {
11>     gRxBufPoolTbl[gRxHeadIndex] = Msg;
12>     gRxBufPoolTbl[gRxHeadIndex]->data[20] = Msg->strength; //ADDED IN
13>     gRxHeadIndex++; gRxHeadIndex %= QUEUE_SIZE;
14>  }
15>  else {
16>    pBuf = NULL;
17>  }
18>      }

19>      

20>      if (pBuf) {
21>  post RadioRcvdTask();
22>      }
23>      else {
24>  pBuf = Msg;
25>      }
26>    }
27>    else {
28>      pBuf = Msg;
29>    }
30>    return pBuf;
31>   }

It is clear that in line #12 we are getting the rssi and it looks to me like we are storing that in gRxBufPoolTbl[gRxHeadIndex]->data[20] However, when I load this program and view the serial output with serial forwarder I still only get the counter coming through. Is there some way I could modify the above code so that the counter is replaced with just the rssi data?

Thanks.

Paul

*****************************************
Paul David Kavan
329 Walter Scott Engineering Center
University of Nebraska
402-472-2764
*****************************************


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