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Reading a 125khz RFID Tag (RDM6300), Help Please

Posted: Tue Mar 05, 2019 8:44 pm
by beneee
Hi All,

Can I ask the wider flowcode community for a bit of assistance please as I can’t get my code to work reliably or consistently and I am probably going about it completely incorrectly.

My end goal is to have a small circuit that will read a 125khz RFID tag (using a RDM6300) and depending on which group the tag is in the circuit will output a signal in binary on 4 pins, each group is could have up to 30 tags in and there will be 4-7 groups. – lots of tags!

The RDM6300 outputs serial at 9600 baud and the signal is high when there is no tag to read.

It only really needs to check once a second but no matter what settings I use on the RS232 component it seems to read nothing and then continue, I thought it was supposed to wait so a valid string and then continue.
On reading up about this I think I will need to use a lookup table for the chip to work out what group it is in (Colours) but again I am not sure how to implement this.

Currently my development circuit is setup so I can see if I can read the IDs reliably and the results are very sketchy.

Each tag has a 9 digit number stamped on it:
e.g. 001378550 (Blue)
Using a serial analyser I have read the output of the RDM6300 using the above tag and it was a 14 Byte string:
2 2 9 0 0 A D 9 F 9 4 8 F 3

After reading a few tags and using process of elimination I have worked out the centre 8 Bytes are the Tag number and all the packet of 10 tags I have read start with a 2 then two bytes then the 8 byte tag id, two more bytes and ending on a 3.

I am using a 16F1937 because I have a lot of them but if you can recommend a smaller cheaper chip that will do the job please let me know.

Here is the Flowcode 8 file as well as a scope trace of one of the tags.

Thanks for any help

Some other Tags I have read for reference
Green: 0011159803 – 22C00AA48FB353
Grey: 0015837585 – 22900F1A991E03
Red: 0011342820 – 22900AD13E4733

rfid read 1.fcfx
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Re: Reading a 125khz RFID Tag (RDM6300), Help Please

Posted: Wed Mar 06, 2019 5:20 pm
by Benj

Your code to wait for a string is nearly correct. Here is how I might do it.

ReadString.jpg (19.33 KiB) Viewed 1566 times

Re: Reading a 125khz RFID Tag (RDM6300), Help Please

Posted: Thu Mar 07, 2019 9:57 pm
by beneee
Thanks for that, it now works reliably, i have got the code to extract the ID from the whole code, rather messily so please feel free to correct.
rfidread2.JPG (41.11 KiB) Viewed 1542 times

The next thing i need to do is find a way of getting the chip to match the 8 byte id which it has just read to one of about 100 in a table/array to get the tag colour, i have read about the Lookup table but can't see how it would work with an 8 byte ID

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rfid read 2.fcfx
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Re: Reading a 125khz RFID Tag (RDM6300), Help Please

Posted: Fri Mar 08, 2019 11:49 am
by beneee
Here is a copy of the tagdata with the group number, how can i put this into a table that the code search through and match with the tag that it has just read.
Can't see how to do it without having pages of If tag=?????? then which will be a really messy way of doing it.

Please help.


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