M6E Nano Barely Working as Arduino Uno Shield

I purchased the M6E and set it up to use as a shield (soldered jumpers and severed the JP1 bridge to use external power, which is a 5v, 3A power supply) and connected it to an Arduino Uno R4 Wi-Fi board. It received power and the status lights worked, and it would allow me to upload sketches, but all the example sketches output “Module failed to respond. Please check wiring”.

I tried connecting it to an old Arduino Uno board I had, and now the sketches seem to be working, but I cannot read/write to any tags. I’ve tried the constant read sketch and it just loops “Scanning” in the serial monitor - I’ve tried with NTAG215s, 9662 ISO18000-6C C1G2 stickers, and a few RFID cards and nothing seems to read.

I’ve also tried the ReadEPC sketch, which works intermittently, but only if I hold the RFID sticker right up to the antenna. It only seems to detect one RFID and then goes back to an endless ‘Searching’ output. If I reset the power, then it will sometimes read one tag and repeat. When it does read using the ReadEPC sketch, the little buzzer sound is very ‘glitchy’ sounding.

I’ve tried the WriteEPC sketch and that doesn’t work at all. It says ‘Failed write’ in the serial output.

I’ve searched the forums and can’t seem to find any answer to this. Could anyone please provide guidance on this or let me know if this is potentially a defective item? Thanks so much.

UNOR4 Wifi: if you try to use softwareSerial it will not work “as it is” due to a problem with the UNOR4 Wifi code. Use Serial1. For more information see ThingMagic/Arduino_lib_special at master · paulvha/ThingMagic · GitHub.

UNOR3: Indeed you need to put the tag on the on-board antenna, but your need to apply better power supply to your UNO or to your M6E seperately. There are many topics on this forum about that.

^ as he said; also see the guide Simultaneous RFID Tag Reader Hookup Guide - SparkFun Learn