[Tinyos-help] Problems detecting a RFID tag with m1-mini

Nivedita K niveditak at gmail.com
Fri Sep 9 14:39:15 PDT 2005


Hi All,
 I am trying to read RFID tags with the Skyetek M1-mini. It seems like the 
command to find tags is being sent correctly to the reader, but i see no 
response even when there are tags in the viscinity. What might be going 
wrong? Could you please help?
 Thanks,
Nivedita.
 -------------------------------
 
The findTags command and findTagsDone event are as below:

---------------------------------

/**

* Tries to read a numTags number of tags. It returns 

* FAIL if the numTags exceeds the maximum number of 

* readable tags, or the reader is busy handling a 

* a previous request. Otherwise, it returns SUCCESS.

* @return SUCCESS/FAIL 

*/

command result_t RFIDController.findTags(int8_t numTags) {

 if ((rfidState != IDLE && rfidState != WAITIDLE) || numTags > MAXNUMTAGS) {

return FAIL;

}

if (rfidState == IDLE) {

if (numTags == 1) {

rfidState = FINDTAGSSINGLE;

packet[1] = SEL_TAG;

}

else {

rfidState = FINDTAGS;

packet[1] = SEL_TAG_INV;

}

}

else {

if (numTags == 1) {

rfidState = WAITFINDTAGSSINGLE;

packet[1] = SEL_TAG;

}

else {

rfidState = WAITFINDTAGS;

packet[1] = SEL_TAG_INV;

}

}

packet[0] = 0x05;

packet[2] = SELECT_TAG;

packet[3] = AUTO_DETECT;

idIndex = 0;

writeIndex = 0;

crc_16(4);

if (rfidState == FINDTAGS || rfidState == FINDTAGSSINGLE) { 

call UART.put(STX);

}

return SUCCESS;

}

/**

* Triggered by RFID reader when the tag ids are reader to be

* read.

* @param uint8_t numTagsFound tells how many tags were read

* @param uint8_t** gives a table of the tag IDs read

*/

default event result_t RFIDController.findTagsDone(uint8_t numTagsFound) {

return SUCCESS;

}
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