ok so im new to RFID and looking for some help here are some questions i have..
1 With a passive tag can you turn it on and off or is it just on all the time?
2 What is the role of the microprocessor in the reader and Do you have to have a microprocessor to control the reader chip?
3 Where can i get some schematics for a reader circuit? (ex. The Texas instruments reader and the like)
4 Does a pasive tag work well in an electrically nosiey environment. (ex under a car hood with all the spark plugs and wires.)
5 Are there any FCC rules and regulations with RFID?
6 Do passive tags work good in a 3 to 5 foot range?
thanks guys i appreciate the help and will probably have more questions soon.
1) Actually the tag is off all the time. The field created by the reader allows the tag to charge with enough energy to transmit its information.
2) It depends on the reader. Of course, there will be an imbedded microprocessor of some sort in the reader, but I assume you are speaking of your own processor. Some readers have a serial interface where you can use a PC or any processor with a serial interface. It depends on the interface of your reader and what you want to do with the information read from the tag.
3) Check the manufacturer's web site. You may first wish to search for reader manufacturers or perhaps search electronic distributors such as Mouser, Newark, Allied, Digikey, etc. for RFID readers then click on the link to display the datasheet.
4) Depending on the noise, you should probably be ok. There is a problem however when there is lots of metal around the antenna or particularly between the reader antenna and the tag. The tag cannot be mounted on metal, but you can punch a hole in the metal or add a plastic spacer to keep the tag away from direct contact with the metal.
5) There are FCC rules for just about anything that transmits an RF signal. If you get a licensed reader you should be ok. If you build one from scratch, then you will have to check the FCC rules. I don't know specifically what they require, I always bought certified RFID readers. The manufacturer of your reader should be able to provide some help.
6) It depends on the antenna design and the surrounding environment (i.e., metal). You can purchase a gate antenna which will read tags that pass through if that would work for your application.
By the way, what is your application and what are you trying to accomplish?
Thanks,
Dale