Passive RFID design assistance

Question

I am looking for the correct RFID tag/reader system for my design. The general block diagram of the system is above. The requirements for the system are as follows:

• Passive tags of some form and an active reader; the reader will be interfacing with an Arduino or equivalent.

• Up to 50 tags can be located in each zone, with a total across all zones of up to 70 tags.

• No writing of the tags is required or the specific locations of tags; just reading which tag is in which zone.

• No time requirement on the scanning; a number of seconds to find all the tags is perfectly fine as the tags are stationary for minutes at a time.

• A low cost system is preferred.

It seems like the best option would be a mid-range transmitter in the center, but I'm not sure about 1) the best system to get the required range, and 2) a way to determine which zone each tag is in. The other option I was thinking was a large NFC antenna/reader in each zone or one encompassing the entire system, but that probably has its own limitations.

Answer 1

If you aim >= 30cm, you definitely need a 128kHz RFID system.

But I doubt that you can read >= 50 tags with RFID at all, because with RFID, each passive tag needs to be powered from the reader.

You might want to try BLE (bluetooth) technology. The latest versions (5.2?) of that standard supports angle detection of the devices.