I'm building a information contact panel that will serve as a point of communication between employees and their company. Part of this process involves putting an ID card to the panel, so it can be 'read' by an RFID reader inside the panel. I'm planning to use anodised aluminium for the front panel, with the rest of the enclosure made from treated wood and plastic.

From what I understand, Aluminium blocks radio frequencies (although this has been debated for certain specific situations). I'm using a cheap/standard RFID reader (RC522). Would cutting a small grill of 1mm or 2mm holes into the aluminium above the reader allow the RFID signal through to be read by the reader? Am also interested in other suggestions/thoughts too. Thanks in advance.

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    \$\begingroup\$ My money would be on no. \$\endgroup\$ – winny Jan 26 '18 at 16:12
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    \$\begingroup\$ It depends on the system you use, despite the name RFID does not always use RF, lots of systems use magnetic coupling \$\endgroup\$ – PlasmaHH Jan 26 '18 at 16:21
  • \$\begingroup\$ Alli foil would stop it, let alone 2mm sheet. Analyse the radiation pattern and coupling modes, then cut slots in the panel to suit, it might work. Better to use GRP or polycarbonate. \$\endgroup\$ – Neil_UK Jan 26 '18 at 16:40
  • \$\begingroup\$ What would be wrong with a toughened glass with a plastic company logo on the back side? \$\endgroup\$ – Solar Mike Jan 26 '18 at 16:46
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    \$\begingroup\$ If the tag/card is also behind the sheet, it should work. \$\endgroup\$ – Brian Drummond Jan 26 '18 at 16:57

You'll find that it won't work, the metal will block the signal from your standard cheap RFID reader completely. Drilling holes will make absolutely no difference.

You would need to cut out an aperture the size of the RFID antenna plus a decent margin (20 mm or more all round?) and mount the reader within that aperture or on the RFID tag-side, not the 'other side' to where your tags are.

One option to consider is putting your reader in a tough plastic box and mounting that on the tag-side of the metal wall, with a hole drilled though to take the cable. Make sure the plastic box keeps the reader inside away from the metal by at least 20 mm, preferable 40 mm or more. You'll find out best by buying one and mocking this up by your wall.

A couple of years ago, I spent a good amount of time investigating RFID technology for use in a machine in a large metal enclosure. One part was me experimenting with a commercial (£30) USB reader and how it would read through different materials when near or surrounded by metal. Was interesting stuff.


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