RFID Modules differences


What is the difference bettwenne those 3 RFID readers?
seeedstudio.com/depot/grove- … -1008.html
seeedstudio.com/depot/electr … l?cPath=52
seeedstudio.com/depot/125khz … th=144_153

Also the “125Khz RFID module - UART” has “Maximum effective distance up to 150mm”
And “Electronic brick - 125Khz RFID Card Reader” has “Max sensing distance: 7cm”

Does the 1st module really have double sensing distance?
Or is it most depending on the antenna configuration?

I want to use it with pet sub-cutaneous RFID chip, so the range is very important.

Thanks for your help.


The value come from datasheet.
And you can see there are similar in distance about 7cm.
Some time when there is no effect by other device could be more longer.

Best regards,