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Author Topic: RFID(CR003t) Not working with uno  (Read 1274 times)
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I got this rfid reader today and it dosnt seem to work.. as i understand, if i connect it's tx to arduinos rx, it should give me an STX value of 02h. Or something like that..
So.. How is this supposed to work exactly..
My code is
Code:
int incomingByte = 0;

void setup() {
  Serial.begin(9600);
}

void loop() {


    incomingByte = Serial.read();


Serial.println(incomingByte,BYTE);
  }

As i understand.. i should get a value.


The rx light is also not blinking..

Help!
Have connected everything besides the pin 2 and pin 3..
As required in the datasheet.. have connected an led which is glowing very slightly. And an Antenna.. I do have RFID tags which are supposedly 125 khz but cnt confirm. BUT, It is supposed to return an value to the rx?
Right?
I get an output of ÿÿÿÿÿÿ

Data sheet :http://www.chinareader.cn/images/_200892414581722949.pdf
« Last Edit: July 19, 2011, 11:49:19 am by akshaykirt » Logged

Manchester (England England)
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You can't just read data if there is no data to read, you have to test if data has arrived from your reader:-
http://www.arduino.cc/en/Serial/Available

Have you connected the ground of your reader to the ground of the arduinio?

What is the exact model number, that data sheet has several different RFID readers.
« Last Edit: July 19, 2011, 04:28:22 pm by Grumpy_Mike » Logged

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Thanks a lot for replying Mike!!. smiley

This is the cr003t. The serial one.. Also, How exactly is this supposed to work then?.. i connected the antenna.. brought a tag closer.. nothing happened. i assume that even if nothing is happening, it is supposed to send some sort of data? to the serial rx of the arduino?

Here are the pictures of what i have exactly done.

https://picasaweb.google.com/akshaykirti/ArduinoRfid?authkey=Gv1sRgCKmGgPe2tJRf


Help!!!. Wht am i exactly supposed to do now.?
« Last Edit: July 20, 2011, 02:25:24 am by akshaykirt » Logged

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Quote
The rx light is also not blinking..
It won't even when it is all working because this LED is controlled by the PC not the arduino.

Quote
Wht am i exactly supposed to do now.?
You need to get it working.
forget the arduino for the moment, disconnect it. Connect an LED anode to the 5V, cathode to a 1K resistor and the other end of the resistor to the RFID output. The LED should not be on. As you bring a tag into the field the LED should flicker, if not your reader is not working, and you will have to find out why.

First of all check and double check the wiring, check that the reader has volts on it with a meter both pin 5 and 27. Also check the ground. Don't bother with the pin 28 LED for the moment.
Check that the coil is being energised, you need an oscilloscope for this, if you haven't got one then make one from the arduino and processing there are lots of examples. Connect a coil of a few turns to the input of the scope and bring it close to the coil, you should see a signal from the field. As you bring the tag into the field you should see the signal flicker. If there is no signal then check with direct connection to the coil, it should be about 60V or more peak to peak. If not then you will have to tune the coil by putting capacitors across it until you get it in resonance, try about 1nF at a time, get the value that gives you a peak output.
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Connect an LED anode to the 5V, cathode to a 1K resistor and the other end of the resistor to the RFID output. The LED should not be on.

Uhh.. Which pin is the rfid output?


Thanks smiley

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Ok. I connected the led anode to +5v. Then the cathode to 1k resistor.. put the end of the resistor to the rx output. connected the antenna.. nthng happend. led didnt flicker.

Did a multimeter test also.. Pins 1, 2, 3, 4, 27 seem to be giving me 4.9v when connected to the common arduino ground which may mean that the power is going through the rfid board.

ok, I made the oscilloscope and connected it to the antenna to the analog read 0 and then the other end to 3.3v for a power supply.. it gave a constant line.. raised due to the current.. so there is no break in the antenna.

secondly.. i think the problem maybe that the tags i have are NOT 125 khz. I grabbed two from the delhi metro and it is nowhere mentioned that they are 125.. nowhere on google also.. i'll be getting the tags tommorrow.. verified 125khz..i'll see then..

Thanks a ton sir.
Really appreciate your help smiley
« Last Edit: July 20, 2011, 02:11:30 pm by akshaykirt » Logged

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ok, I made the oscilloscope and connected it to the antenna to the analog read 0 and then the other end to 3.3v for a power supply.. it gave a constant line.. raised due to the current.. so there is no break in the antenna.

No you were looking for a 125KHz signal here when the coil was connected to the reader. So a constant line is bad if it is connected to the reader. Normally this should be a big signal on this coil.

The LED is to be connected on the TX data output of the reader, it will flicker when the reader outputs data.
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ohhhhhhkkkkkk.. so what exactly should be the oscilloscope output?

a 125 khz signal?.. hmmm..

this is the coil they gave me

https://picasaweb.google.com/akshaykirti/ArduinoRfid?authkey=Gv1sRgCKmGgPe2tJRf#5631524975785441250



http://accrochages.drone.ws/en/node/90

Again, i connected one end of the antenna to the +3.3v and other to the a0.

« Last Edit: July 20, 2011, 02:54:00 pm by akshaykirt » Logged

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That scope is not fast enough it says:-
Quote
gives us the absolute maximum bandwidth of the system, or 240Hz
You are looking for a 125KHz signal. Maybe these sort of scopes aren't fast enough for your needs here.

Quote
Again, i connected one end of the antenna to the +3.3v and other to the a0.
Why? You are trying to see if the reader excites your antenna (coil), so connect it to the reader and connect the oscilloscope to one end of the coil, then if you see nothing the other end of the coil. There must be a common ground connection between your oscilloscope and the reader when you do this.
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Hey, This is what i got.. connected the vcc's and grounds of the reader to the arduino(using it as power supply).. then connected one end of the antenna to reader antenna in(pin15).. othr end went inside the oscilloscope in. a0 of the arduino

result is a consistent waveform generated

http://picasaweb.google.com/akshaykirti/ArduinoRfid?authkey=Gv1sRgCKmGgPe2tJRf#5631529536125655794

Have a look smiley


Will get those tags tomorrow though..

ok intresting development.. i touch the coil and these waveforms increase(y axis). ans put it on plastic, they well are almost neglible.. so guess no signal.. this picture is when the antenna was kept on the bed
« Last Edit: July 20, 2011, 03:19:19 pm by akshaykirt » Logged

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Muahahhaahah.. It works smiley. Tags were wrong earlier.. :/
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Hey akshaykirti

Did you get your reader to read tokens or smartcards from the Delhi metro?

If so, which one are you using, or what frequency do the tags use?  125kHz, 13MHz or something else?

Many thanks!
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Hi,

I had the 125khz reader and had to get separate tags. The delhi metro ones are 13mhz i believe.
I got some module from a hobby shop in delhi. I suggest you to get the ID series, much better support.

https://www.sparkfun.com/products/11827
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For hobby projects, 125hz is cool. Mostly because of the easy availability
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Thanks but I want to read the Metro smartcards and tokens.

Have you tried using a 13MHz reader with them?

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