[aprssig] APRS RFID apps? (Hot Spots design!)
winston at winston1.net
Wed Feb 10 13:40:50 CST 2010
How do you define the location of the reader? I'd sorta envisioned a
counter value so that instead of just incrementing .01 latitude, you
could do a spiral effect around the reader using a +.01 lat, +.01 lon,
-.02 lat, -.02 lon, +.03 lat sort of stepping. which would be reset by
the config every time the reader either hit a step value (ie 20 tags
read) or a time value (every 30 minutes)
Quoting Bob Bruninga <bruninga at usna.edu>:
> OK, here is a draft concept for APRS RFID:
> APRS RFID CONCEPT
> The following is a possible design of an innexpensive ham radio APRS
> RFID system for application in large venues such as the Dayton
> Hamvention to keep track of walking operators. Ten Inch round RFID
> yellow/red hot spots are placed in each doorway or special location.
> APRS participants wear a $2 RFID card in their shoe. When they
> cross an APRS hot spot, the hot-spot reader sends the RFID to a
> centralized on-site PC that associates that RFID to a callsign and
> then generates an APRS packet on the APRS network showing that
> person at that location.
> APRS RFID READER: A $25 RFID reader is the only new hardware required.
> The 9600 baud serial output from this device is connected to a PC
> for one-door applicaitons or, for large multi-door locations to a
> typical APRS "tracker" which has special parsing code to convert the
> RFID number into a speical AX.25 short-range packet (preferably on a
> separate frequency from he national APRS channel). The RFID packet
> format is:
> Where the SSID of the hotspot reader (I) can contains 4 bits of
> additional info such as direction, speed, etc. The initial "RF" will
> make this an ALTNET (non-APRS) packet, and the DDDDD-D:DDDD is the
> 10 byte HEX ASCII RFID code.
> CENTRAL PROCESSOR:
> The central processor receives the above RIFID from a given SPOTID
> and then matches the RFID to a callsign and generates the following
> standard APRS position packet for the local network (and/or APRS-IS):
> CALL-7>APRFID,WIDE2-2:!DDMM.mmN/DDDMM.mmW$DDDDDDDDDD free text
> Where the SSID is always -7 from any card operated under that
> callsign. Where a special unique RFID SYMBOL is used, and the RFID
> number is included in the first 10 bytes of the packet. The Free
> text is associated with that hotspot. Such as "Entering HARA",
> Leaving HARA, or ARRL Booth, or KENWOOD Booth etc.
> The position is built by incrementing .01 Latitude from an origin on
> the map associated with that RFID hot spot. This way, everyone that
> crosses that hot spot will appear in a neat table on the map.
> This CALL-7 is used for ALL RFID tags that might be owned by that
> ham CALL so that no mater what shoes he is wearing or how he is
> reporting his position, they will all overwrite each other so that
> only the most recent one ever exists in APRS.
> CALLSIGN ASSOCIATION: The initial RFID number to callsign
> association is made at the central processor or point-of-sale of the
> RFID card -OR- anywhere else that a keyboard or keypad is attached.
> It doesnt matter, since EVERY such association will generate the
> above APRS packet and from that , ALL systems locally or globally
> can collect these associations from the APRS-IS. Also clubs with
> large numbers of card holders can submit RFID files to pre-load the
> APRS-IS system. Or anyone with any APRS system can manually prepare
> the above packet and send it once from their HT or Mobile. From
> then on, the association is made.
> RFID READER SERIAL DATA: The RAW output from the RFID reader is at
> 9600 baud and can be read o any serial port. The format is as
> Where S is STX (02h)
> DDDDDDDDDD are 5 bytes in 10 ASCII HEX characters
> KK is a HEX checksum
> C is CR and L is LF and E is ETX.
> Special code in a "tracker" type pic processor reads this and
> generates the local RFID Reader packet which is sent on a separate
> frequency to the central processor. Or for one-door applications,
> direct into a local PC connected to the APRS system (RF or Internet).
> RFID Tag (125 KHz): The Credit card sized RFID's are from $2 down to
> $1.50 depending on quantity. They are available from:
> Anything I missed?
> Bob, WB4APR
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> aprssig at tapr.org
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