RFID large board -

I have read through a ton of the RFID topics. I don’t believe anything like this has been asked before.

I have setup several basic RFID readers before, but I now have a new project and can’t seem to figure it out.

I want to have a large “pad”. About 3ft. by 3ft. The goal is to allow for 1, or many ( up to 10 or so tags ), passive tags to be on this pad and be able to tell which ones tags are on the pad.

I have created a crappy version of the pad making my own antenna and it will read one, but not more than 1 tag. This is using a very cheap $5 reader I bought a while back.

I am open to making my own antenna, or buying one. I think the more important part would be the reader. One with anti-collision I am guessing.

The issue is I do not need “range” in the Z direction beyond maybe an inch or two incase 2 tags are on top of each other.

Mainly just need to read from the top of the bottom, and left to right on the 3ftx3ft surface.

It may not be possible, or they may be a better option than RFID. I do need to be able to tell the tags apart to tell who they belong to, so basic sensors for presence or weight won’t do.

This is for a kids game were making for a party, and each child will get a tag to throw.

Any insight is appreciated!!

Thanks,
B

I have read through a ton of the RFID topics. I don't believe anything like this has been asked before.

Well I did this five years ago:- http://www.thebox.myzen.co.uk/Hardware/RFID_Sequencer.html

Their is also this https://www.sparkfun.com/products/14066

Look at the video on this site.

WOW quick reply! thanks.

I actually did see spark fun reader, but its $200. I was hoping to not spend that much on this project.

I love the RFID Sequencer page but I was hoping to do this with a single reader and single antenna.

Looks like the $200 reader might be my only option :(

Thanks again! B

Going to UHF is the only way to get reliable multi tags to read. You can do a small bit of anti collision with the lower frequencies but that is up to the specialised design of the tag. Basically they hold off for a random time if they detect a collision. This only works on a limited number of tags and sometimes they are not all read.

Spark fun isn't the only UHF receiver in town but it is the best supported for hobbyist and is amongst one of the cheapest.

again thanks for the amazingly quick replies!

OK, well I will do more research into the UHF readers. I have not used them before.

If you have worked with these and have any recommended places to look for readers / passive tags I would love to see them. If not, Thanks again for your time! really helpful stuff.

If you have worked with these

I used to work professionally with RFID access control systems. However, the company I worked for did not do any products using UHF readers, we kept to the low frequency 125 - 140KHz and the RF 13.5MHz.