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Topic: 2.4GHz active rfid reader long range with Arduino Mega 2560 (Read 7477 times) previous topic - next topic

kamalanathen89

hi.....
My project is RFID guided automatic delivery robot

i am use 2.4GHz active rfid reader (http://www.aliexpress.com/snapshot/6035553745.html ).

So, i have problem to interact arduino mega to this 2.4GHz active rfid reader,  i have been trying to interact arduino mega to 2.4GHz active rfid reader by using this RS 485 ic ( http://my.element14.com/exar/sp485eep-l/transceiver-rs-485-dip8-5v-485/dp/9387188?ref=lookahead), but no luck it is still not working  !!!!

Can someone help ??

Grumpy_Mike

#1
May 13, 2014, 05:30 pm Last Edit: May 13, 2014, 05:39 pm by Grumpy_Mike Reason: 1
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Can someone help ??

Only if you post your code and the schematic of the interface you have wired up.

It also helps if you have a data sheet, all those you posted do not give enough information about the data format expected.
There is no mention of what baud rate it is using or how to switch between RS485and Wiegand.

For example is the device sending tag information only or does it have to have something sent to it to enable certain modes.

Also have you shorted the green and grey wires together?

I notice it says:-
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Reliability   Thunder protected, water proof and striking resistant,

Thunder resistant is easy, few electronic devices are frighted of loud noises.

kamalanathen89

#2
May 13, 2014, 06:26 pm Last Edit: May 13, 2014, 06:36 pm by kamalanathen89 Reason: 1
i already attach picture of connection of rfid to arduino.

im just started this project. i take this circuit from another project but it is not working and i dont know how to troubleshoot.
i used RS 485 ic ( http://my.element14.com/exar/sp485eep-l/transceiver-rs-485-dip8-5v-485/dp/9387188?ref=lookahead )

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Also have you shorted the green and grey wires together?


yes, i already shorted.

Grumpy_Mike

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i already attach picture of connection of rfid to arduino.

No you didn't.
But thanks for doing so now. It looks like that is wired up correctly?

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i dont know how to troubleshoot.

So you look with an oscilloscope at the yellow or blue line and see if you can detect any activity.
If you can measure the signal and try and determine the baud rate. Then set the same baud rate in your sketch.
Then look at the R out signal into the Arduino, is this the right way up for TTL serial data. That is when there is no activity the line sits high? If not then swap over the yellow and blue wires.

You still need a proper data sheet, those you have posted already are not good enough.

kamalanathen89

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But thanks for doing so now. It looks like that is wired up correctly?


i'm not sure,because take the circuit from another RS 485 interface project. Then, i tried to apply it in my project, but not working.

i also found another manual datasheet from the manufacturer. I have attach below related document.  I think it might be helpful....

Grumpy_Mike

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i also found another manual datasheet from the manufacturer. I have attach below related document.  I think it might be helpful..

No not really they just document some, so far unknown, software.

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Then, i tried to apply it in my project, but not working.

So have you done the things I said in my last reply?

You need an oscilloscope. If you have not got one then you can not do this project with the amount of very poor documentation you have shown so far.

kamalanathen89

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So you look with an oscilloscope at the yellow or blue line and see if you can detect any activity.
If you can measure the signal and try and determine the baud rate. Then set the same baud rate in your sketch.
Then look at the R out signal into the Arduino, is this the right way up for TTL serial data. That is when there is no activity the line sits high? If not then swap over the yellow and blue wires.


hi.....

i already tried test  using the connect i mention below and i got reading on an oscilloscope. i used MAX 483 ic ( http://my.element14.com/maxim-integrated-products/max483cpa/ic-cmos-bus-transceiver-dip8-483/dp/9725229 ).

Then, i dont know how to interface to arduino mega.. do u have any tutorial for interfacing to arduino?

TQ

Grumpy_Mike

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and i got reading on an oscilloscope

So is it the right way up and what is the baud rate?

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Then, i dont know how to interface to arduino mega.

Just wire it up like you showed. You might want to use one of the Mega's other serial ports like 1, 2 or 3.

kamalanathen89

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So is it the right way up and what is the baud rate?

Baud rate is 38400..

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Just wire it up like you showed. You might want to use one of the Mega's other serial ports like 1, 2 or 3.

i just connected the wire to serial port 0 (TX 0 & RX 0). But i don't know how to read, is it normal serial print?
i tried normal serial print,but no data.

Grumpy_Mike

The serial port 0 is already connected to the USB to serial converter so you can't use that.
You read with a serial read command not a print.
Look up serial read in the referance, if you still have trouble then post your code. Use code tags.

kamalanathen89

i already tried serial read in Arduino, but i could not get any reading from arduino serial print.
Then i used HyperTerminal software , i managed to get the reading. I attach the reading from HyperTerminal software below.
Do you have any sample arduino coding for serial read or any related to this RFID reader?

Tq...:)

Grumpy_Mike

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Do you have any sample arduino coding for serial read or any related to this RFID reader?

Sorry no.

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Then i used HyperTerminal software

So what hardware did you use to get a connection between your reader and your PC?


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i already tried serial read in Arduino, but i could not get any reading from arduino serial print.

So it sounds like your code was poor. You need to post it for more help.

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