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Author Topic: Parallax RFID Read/Write Module 28440  (Read 4942 times)
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Brooklyn, NY
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yes, but then it strips out the colors. I think that they are more beneficial than the scrolling box....
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But your code is mangled, and the post is a pain to scroll through and the colours are not too important once you know how to program and we are doing the answering anyway
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Thank you all for doing all of this work. I'm working on a Mega 2560 and cannot get this to work at all. I tried many examples, including the ones on this page. If it makes any difference, I'm using the "Blue Eye Key Fob Tag" from Parallax that uses the EM-4100 tech.

According to Arduino's SofwareSerial example, (http://arduino.cc/en/Tutorial/SoftwareSerialExample) "Not all pins on the Mega and Mega 2560 support change interrupts, so only the following can be used for RX:  10, 11, 12, 13, 50, 51, 52, 53, 62, 63, 64, 65, 66, 67, 68, 69"

So I naturally just changed the RX pin to any one of the above. I only want to read tags, not write them, so I suppose TX doesn't really matter, but I hook it up anyway. Still nothing.


Can anyone give me any pointers for a Mega 2560?
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I'm trying to get this to work with an Arduino Mega 2560. I'm also working with the Blue Fob tags sold by Parallax (https://www.parallax.com/StoreSearchResults/tabid/768/List/0/SortField/4/ProductID/503/Default.aspx?txtSearch=blue+fob) which work on the EM-4100 tech, which I suppose we are referring to as 'legacy'.

I cannot for the life of me get a read. In addition, the LED on the RFID reader is always GREEN, not red as I believe it should be, correct? According to Arduino's SoftwareSerial example, though: "Not all pins on the Mega and Mega 2560 support change interrupts, so only the following can be used for RX: 10, 11, 12, 13, 50, 51, 52, 53, 62, 63, 64, 65, 66, 67, 68, 69" (http://arduino.cc/en/Tutorial/SoftwareSerialExample so I use 10 typically for RX and anything else for TX, but that really shouldn't matter since I only want to read.

Can anyone give me any pointers?
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The blue tags you are using are the 'legacy' tags so you need to use the RFID_ReadLegacy command (0x0F) in order to get a valid read.

Per the datasheet, "A visual indication of the RFID Read/Write Module’s state is given with the on-board LED (Light Emitting Diode). When the module is successfully powered-up and is in an idle state, the LED will be GREEN; when the module is in an active state (for example, searching for a valid tag or performing an operation on the tag), the LED will be RED."

So the fact that it stays green is no surprise, it means that at least the module is powered up.  Try sending a command and seeing if it flashes red, if so, then you know the Arduino and the tag are communicating. If not, check your comm set up, are Tx and Rx reversed? are you using softwareserial or the older NewSoftwareSerial (yes it is confusing). Try it out on another serial device or on an Uno which this was coded for.

Good Luck
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