RFID Tag Problems
karlprescott
Posts: 15
in Propeller 1
I have been testing a basic program where I present a RFID tag and it displays the ID number. For most RFID tags it works as expected. But I have one set of tags that works a few times but then causes it to crash when presenting the tag. I have tested the set on a windows based reader and it works fine every time.
Comments
Is this a Parallax reader and are you using Parallax tags?
Are the working and failing tags that same part number?
Also, post your code.
con _clkmode = xtal1 + pll16x _xinfreq = 5_000_000 CLK_FREQ = ((_clkmode - xtal1) >> 6) * _xinfreq MS_001 = CLK_FREQ / 1_000 con TX_PIN = 0 'Display Port BAUD = 19_200 RFID_RX = 17 ' RFID on PAB RFID_EN = 16 servoPin = 10 ' Servo signal to this I/O pin-change if needed con #1, HOME, GOTOXY, #8, BKSP, TAB, LF, CLREOL, CLRDN, CR, #14, GOTOX, GOTOY, #16, CLS ' PST formmatting control LAST_TAG = 3 ' tag #s are 0..LAST_TAG obj term : "FullDuplexSerial.spin" rfid : "FullDuplexSerialPlus.spin" var byte teststr[32] ' string buffer byte tagbuf[10] ' tag buffer pub main | idx, b setup ' start program objects 'term.start(TX_PIN, TX_PIN, %1000, BAUD) ' start LCD terminal 'rfid.start(RFID_RX, RFID_RX, %1100, 2400) ' open-drain serial for RFID repeat term.str(string(12," Wait Ball:", CR)) accept_tag(@tagbuf) ' wait for tag term.str(string(12," ID ")) term.str(@tagbuf) term.tx(CR) pause(3000) PUB CenterServo(n) | tInc, tc, tHa, t, c ctra[30..26] := %00100 ' Configure Counter A to NCO ctra[8..0] := servoPin frqa := n dira[servoPin]~~ ' Set up cycle and high times tInc := clkfreq/1_000_000 tC := tInc * 21_500 tHa := tInc * 1500 t := cnt ' Mark counter time repeat c from 1 to 100 ' Repeat PWM signal phsa := -tHa ' Set up the pulse t += tC ' Calculate next cycle repeat waitcnt(t) ' Wait for next cycle pub setup '' Setup IO and objects for application term.start(TX_PIN, TX_PIN, %1000, BAUD) ' start LCD terminal term.tx(17) 'Turn Display Light on rfid.start(RFID_RX, RFID_RX, %1100, 2400) ' open-drain serial for RFID pub accept_tag(p_buf) | c, idx '' Enables RFID reader for ms milliseconds '' -- reads tag bytes (if available) into p_buf bytefill(p_buf, 0, 10) ' clear old data rfid.rxflush ' clear rx buffer low(RFID_EN) ' enable reader repeat c := rfid.rx until (c == $0A) ' wait for $0A (LF) repeat 10 ' rx 10 tag bytes byte[p_buf++] := rfid.rx input(RFID_EN) ' disable reader pub get_tag_id(p_buf) | tidx, p_check, bidx '' Compares tag data in ram (at p_buf) with known tags '' -- returns tag index (0..LAST_TAG) if found '' -- returns -1 if tag not found repeat tidx from 0 to LAST_TAG ' loop through known tags p_check := @@Tags[tidx] ' get hub address of tag being tested repeat bidx from 0 to 9 ' loop through bytes in tag if (byte[p_buf][bidx] <> byte[p_check][bidx]) ' if byte mismatch quit ' abort this tag if (bidx == 10) ' if all bytes matched return tidx ' return this tag id return -1 ' return not found pub pause(ms) | t t := cnt - 1088 ' sync with system counter repeat (ms #> 0) waitcnt(t += MS_001) ' delay 1ms (syncronized) pub high(pin) '' Makes pin output and high outa[pin] := 1 dira[pin] := 1 pub low(pin) '' Makes pin output and low outa[pin] := 0 dira[pin] := 1 pub toggle(pin) '' Toggles pin state !outa[pin] dira[pin] := 1 pub input(pin) '' Makes pin input and returns current state dira[pin] := 0 return ina[pin] dat { tags data } Tag0 byte "7A00219388" Tag1 byte "7A00216BC1" Tag2 byte "7A00216CAE" Tag3 byte "7A0021A6E3" Tags word @Tag0, @Tag1, @Tag2, @Tag3 Name0 byte "PINK", 0 Name1 byte "ORANGE", 0 Name2 byte "BLUE", 0 Name3 byte "YELLOW", 0 Names word @Name0, @Name1, @Name2, @Name3ModEdit: Code tags added.
Post your code between code tags see "C" in posting header... B I U C etc.
Jim
Parallax makes high quality products that are rarely faulty but you never know what you will get from ebay.
Did the seller claim all the tags were from Parallax?
Aren’t tags just tags? Can you not use any rfid tag with a parallax reader?
https://en.wikipedia.org/wiki/Radio-frequency_identification#Frequencies
My employer rents a loft in an upscale apartment complex for us to work off-site. It uses RFID keys -- and we only have one. We looked them up and they are listed as 125kHz -- the same as the Parallax reader. Still, we couldn't read the key because there is a secondary protection scheme embedded in it. We had to take the social engineering route to get spares without incurring the $150 per-key charge.