RFID solution for reading multiple tags

Question

I am working on a Robot-project where a sub task is have to check how many and which RFID-tags are placed in a bucket.

Multiple tags will be placed into the bucket - so I run into the problem with RFID-tags colliding with each other. The reader will be connected and programmed via Raspberry Pi. From my research so far I have come up with the following 3 options:

1 RFID reader at the buttom of the bucket. This has to be a reader able to read the multiple tags at the same time, since the tags will be laying on top of each other. Example of reader: https://www.sparkfun.com/products/14066

2 RFID reader on the side of the bucket. Should read the tags passing by as they are thrown into the bucket. Would not required that the RFID reader is able to read multiple tags at once, but the reading should be fast enough to catch them passing by. Example of reader: ADAFRUIT PN532 NFC/RFID

3 Same concept as 2 but minimizing the space and using slides to hopefully give a bit longer time for reading the tags. Example of reader: Same as in 2

I am aiming for the most simple and most secure solution.

How would you guys do this, and what kind of RFID hardware would you recommend to go with the Raspberry Pi connection.

Answer 1

In RFiD world, you 3 type of hardware.

• The RFiD LF (about 125kHz).
• The RFiD HF (13.56MHz).
• The RFiD UHF (444MHz or 866MHz band).

If you want to detect multiple tags, you need to have a reader with anticollition protocol. I recommend using RFiD HF because the antenna design and debug is easier than UHF. You can use the OMNIKEY multi ISO reader which is a good product. You can find it on the RFID SHOP website.