Newbie help

spaceflunk

Hello
I am having a project in school where i need to use RFID and i have looked at this:

RFID Reader Module (#28140)
RFID 54 mm x 85 mm Rectangle Tag (#28141)

Now i need a Basic stamp, but what should i get ?
There are going to be 3-4 tags, and the points is that when tag 1 are over the reader, i am getting a digital signal saying 1 maybe and when tag 2 is over the reader i am getting out a digital 2 and so on. Is that possible with these components, and what do i need?

Thank you so much

spaceflunk

Is has to be parallel the output.

Mike Green

The RFID Reader puts out a 2400 Baud character sequence when it is triggered, so you will need some kind of processor like a Stamp to trigger the RFID reader, receive the characters, look up the ID, and indicate which ID was found (or indicate that it was invalid). If you look at the RFID page in the Parallax Store, you'll find links to datasheets and sample programs for both the BS1 and BS2. The BS1 would work, but it has limited capacity if you should ever want to expand your system. For 3-4 tags, it would be fine. If you ever have to replace a tag, you'd need to modify the program and reprogram the BS1 (very easy ... but you need a PC available). Any BS2 model would work as well and could hold a much more complex program if that's what you might want. For example, the BS2 could have a small display and keypad or buttons attached and the program could be self-maintaining in that you could delete, add, or modify the RFID tag associated with each output without needing to change the program, just with the RFID controller. The BS1 has a total of 8 I/O pins and 2 would be needed for the RFID reader. The other 6 could be used for the digital outputs (0V/5V, up to about 20ma each). The BS2 has a total of 16 I/O pins. If you need to control a higher voltage or more current than that, you can add a chip like the ULN2803 which can drive small motors or solenoids. See the What's a Microcontroller tutorial that you can download from the Stamps in Class page on Parallax's website. It has information on controlling motors and relays with a Stamp.

The Nuts and Volts column (#120) with a link on the RFID page of the Parallax Store has a complete example for a BS1 of what you want to do. Have a look at the article.