My project is about rfid reading cards/tags, and based in meeting criteria triggers a relay and updates OLED display. Am using:
ESP32, RC522, 0.9" OLED, 5v relay module
Everything working fine on breadboard (reader scans cards/tags 0-1cm away).
Issue:
When I printed a project box (3d print , 9600 resin SLA, 2mm thickness) the reader can't read the cards/tags -although reader is surface mounted on box top from inside , and I scan cards on box top from outside, those 2mm of material is killing signal.
Having an opening in the box to expose the reader won't work..
Appreciate recommendations for a way to amplify the signal or suggestions for a suitable reader that works with ESP32 and doesn't hurt the wallet!
I see two possibilities right off the bat; either there's something in the resin that's blocking RF (and I'd be considering using a different material, as I just successfully read a card thru 3mm of PLA) or there's some RF interaction between the ESP32 (are you using the WiFi?) and the RC522 that's down to the physical placement of the two devices.
I don't imagine you're going to have any luck finding a way to amplify the RC522's signal.
It sounds like a great project! The 2mm box material is probably blocking the RFID signal. You might try using a more sensitive reader or testing different antenna placements. Sometimes even a thin section of material that’s easier for the signal to pass through can help. Hope you find a solution that works!
A 2 mm thick SLA resin wall at 13,56 MHz usually does not by itself block the RFID signal, but the way the RC522’s antenna is mounted relative to the resin can detune the antenna and reduce the coupling to the tag enough that reading fails.
The resin might act as a dielectric load on the PCB antenna, shifting its resonance away from 13,56 MHz and significantly reducing the magnetic field strength and if the antenna is in direct contact with the resin, this effect is stronger.
Leaving an air gap between the antenna and the resin, a couple millimeters, might restore most of the read range.
Ok, but could you cut a window for testing, then glue something much thinner over the window? I'm thinking even a layer of the clear plastic packaging many grocery products come in now.
Even if it's just for testing(you can always print another unit), it will prove your suspicion about the material - or not.
You have to first read the signal before you can amplify it. Print some test pieces to determine the reliable thikness. Consider normal PLA as well, I am not familiar with 9600 resin SLA.
Thanks all for the replies!! It turned out to be a stupid mistake from my side!
The setup without 3d print was on the kitchen counter left side, the setup with 3d print was on the counter right side (right above the power outlet for kitchen appliances!),
the power outlet was too close and killing signal! Am getting 4-5cm easily now even with the 3d print.
Another lesson for me, it's never the technology, always the user
