RFID protocol ideas

Wireless & IoT
1

Hi

Im trying to write a protocol based soft to my hardware. The rules are that i got 1 reader, and 10 tags. I’ve made a simple soft which algorithm is : each tag has unique adress, and each reader(receiver) seraches for incoming packet from all of tags by changing own adress - in short way it means that in loop all tags are sending packets to differnet reader adres - which chagnes its own adress (reader is one). But it seems to be not professional soultion, which now im looking for. I was thinking about two possible ways. Fisrt is : “ping way”- each tag is set to be a receiver with ACK. And all tags got same adress, but data which they’re sending is unique - disadvantge - what if two tags are going to send packet in the same time ? How to prevent collisons ? And the second way which i was thinking about is :reader is transmitter with ACK, and pings all tags which has differenet adresses - but its like my first soultion - i need to give a time for packet to be received.

In conclusion - Id like to know what are Your sugeestions and maybe any ideas to make a nice working protocol.

PS. im working on nrf24l01 based stuff, but still got no results with working with pipes

WJ

2

HI there a solution i have seen some were i think is

make your host send a comand lique 0xXX and al tags respond to it with a 4 byte of ‘0’ and only 1 bit active chosen randomly.

YOu would recive something like

0101000000…01000010000 so now you resend another command with the first 1 just and everithing in 0 so only that tag should reply with its serian number…

Host sends

0xXX

tangs responce

Tag 1

0b0001000000000000000000000000000

Tag 2

0b0000000010000000000000000000000

Tag 3

0b0000000000000000000010000000000

…

…

…

you showld recive in the host

0b0001000010000000000010000000000

you send back

0xXX 0b0001000000000000000000000000000 request KEY COMMAND

and only tag 1 should response. in the eventuality that tow tags send same bit they key CRC wound match because of colition. So you start again from first parte. Another thing Active tags should not send another bite system if they are activated already.

i hope to have help