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Interfacing RedBee Reader

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jonsmith0 View Drop Down
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    Posted: 03 February 2011 at 1:10pm

Hi,


Im trying to work something out for my university project and I wanted to know wether it is possible to pulse the 'OUT' pins individually on the RedBee RFID reader.


e.g. when one RFID card is swiped the 'OUT1' pin is pulsed and when a different RFID card is swiped then the 'OUT2' pin is pulsed.


Or if that can't be done then do you know the source code (preferably in C as thats what the coding is wrote in) or the way to read the asynchronous data packet that is sent from the RedBee reader when the card is scanned to a Microchip PIC18f45k20 Microcontroller and how that would give an output to allow me to use it to activate a scanning off my Digitran KL0045 4x3 matrix keyboard for the 10 digit passcode I will assign to the card.


I need it to be able to tell which card is which as each card needs a different access code.


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amal View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote amal Quote  Post ReplyReply Direct Link To This Post Posted: 03 February 2011 at 1:48pm
Hi Jon, welcome to the forum.

Unfortunately the RedBee cannot do this. However you can accomplish this using a TTL reader like this one, coupled with a microproc like the one you have listed. The serial data is very simple; when a tag is read the reader kicks out the tag ID and a CR (ascii char 13). Very easy to read.

As for programming cards, there is no way to do that with EM4102 tags. Each card comes from the factory with a unique tag ID already, so you just read the card and assign the pin you want it to activate on your microproc.

If you need to associate passcodes or other data with a tag, then really the only way to do that with read-only tags like the EM4102 is to create a cross reference database that stores the tag ID along with the associated data you want to tie to that tag. For example, if the tag ID is 1234567890 and you want to tie ABCDEFG with it, upon tag read you would search the table to find 1234567890 and read the associated data ABCDEFG, then do something with that data. For most projects though, the unique tag ID itself is all that is needed since each tag ID is unique and cannot be changed.

Hope that helps.

Amal ;)

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Post Options Post Options   Thanks (0) Thanks(0)   Quote jonsmith0 Quote  Post ReplyReply Direct Link To This Post Posted: 03 February 2011 at 2:24pm
Hi Amal,

Thanks for the reply ill have a look into that, but reading my post again now i don't think i have explained how the design works properly.

The design is a three-tier access system, the first tier has a keyswitch to initialise the opening sequence, the second tier is the RFID reader that I was planning on using the OUT pins but as you mentioned this won't work, thats why i need to know how to read the data sent out buy the RFID reader on a PIC18f45k20, the microcontroller is supposed to read the ID of the RFID card and using that number be able to find what 10 digit access code is needed for the third tier, which is the keypad, where the code found in the second tier is entered into the keypad, then the microcontroller activates the unlocking systems (relays, solenoids, LED's etc)

the part i am having trouble with is how to read the ID from the RFID card in the program, after that i think i can get it to scan for the codes I want.

eg swipe 1 card it gives the RFID cards ID as 1234567890, the microcontrollers program reads that number then i link it to look for the keypad code 0987654321, which is entered on the keypad and the doors unlock.

I was hoping i could do it with the redbee (i have the RedBee Experimenters kit with the Xbee Modules) as i only have about 8 weeks to build and program the project and don't really have the time to look into redesigning the system.

If the above can help in solving my problem in anyway that would be great and thanks for the help.


Edited by jonsmith0 - 03 February 2011 at 2:26pm

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Post Options Post Options   Thanks (0) Thanks(0)   Quote amal Quote  Post ReplyReply Direct Link To This Post Posted: 03 February 2011 at 2:37pm
Ok, I get it now.

You will want to use the microproc's I/O pins to actuate the various sets of locking mechanisms and indicators based on which card ID is presented, so you will need to get the Parallax TTL reader connected to it. Its simple data output makes for easy parsing in your microproc code. The RedBee can't do this on it's own, and the TTL interface is more complex so getting tag ID data out of it is more difficult.

I assume the microproc will be programmed with tag IDs and keypad passcodes and all that so it does not have to interface with an external database?
Amal ;)

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Post Options Post Options   Thanks (0) Thanks(0)   Quote jonsmith0 Quote  Post ReplyReply Direct Link To This Post Posted: 04 February 2011 at 6:39am
Ye the program on the chip will contain all the necessary codes and combinations it needs.

What pins would i connect the reader to on the microcontroller

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Post Options Post Options   Thanks (0) Thanks(0)   Quote amal Quote  Post ReplyReply Direct Link To This Post Posted: 04 February 2011 at 10:08am
The pins on the PIC are programmable, meaning you can set their function in code. That's why each pin has so/many/options/separated/by/slashes... each acronym between each slash is a programmable option for that pin.

You have 36 I/O lines to choose from, so pick one that can be programmed as an I/O line and/or be put into INPUT mode, and that's your pin.
Amal ;)

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Post Options Post Options   Thanks (0) Thanks(0)   Quote jonsmith0 Quote  Post ReplyReply Direct Link To This Post Posted: 17 February 2011 at 1:55am
hi amal,

Got the parallax reader now, do you know what the C18 code would be for activating the reader to search for cards then receiving and processing the ASCII number from the reader so i can link it to the rest of the program

As i said before i'm using the PIC18f45k20, as well as the reader i have a 3x4 keypad, 3 bi-colour leds (Red/Green), a key switch, a microswitch and a servo connected to the chip.

Any help you could give on the programming would be great as i am not familiar with programming.

Jon

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Post Options Post Options   Thanks (0) Thanks(0)   Quote amal Quote  Post ReplyReply Direct Link To This Post Posted: 17 February 2011 at 8:54am
For the parallax reader, there is no command to activate it. All you have to do is tie the ENABLE pin to ground. Once tied to ground, the reader will be active and any tag IDs read will be output through the SOUT pin at TTL 5v levels and 2400 baud.

As for programming the PIC, I can't help you. Unfortunately I'm not the versed in PIC programming, but it is on my list of things to learn.
Amal ;)

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