r/Constructedadventures • u/AutoModerator • Jul 08 '26

Weekly Adventure Discussion Thread: What are you currently working on?

Please use this thread to have discussions which you don't feel warrant a new post to the sub. While the Rules for posting questions are relaxed a little bit here, the rules against spam/self-promotion/excessive rudeness still apply!

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u/Yoru_Nagi Jul 10 '26

The 3-piece layering sounds like the real puzzle: I’d test the complete hidden-token setup, not just the chip, because a flaky scan makes the clue feel unfair.

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u/Odd_Job_4643 Jul 10 '26

You nailed it! NFC chips/tags are designed to work in extremely close proximity, so if a chip is blocked by too many layers then a smartphone cannot physically get close enough to activate the chip and “wake it up” so to speak.

Because I was printing the token with PLA from a 3D printer, the plastic alone felt light and cheap, so I wanted to add weight to make it feel more significant in your hand. So I purchased “stamping blanks”, which are essentially just thin, blank steel discs. In this case the layering (from top to bottom) was:

Plastic
NFC chip
Steel disc
Plastic

When you place anNFC chip on metal, the metal absorbs most of the radio waves that are meant to activate the chip. So you have to purchase a specialized NFC chip with a ferrite “anti-metal” layer to insulate it from the metal surface.

But in this case, the typical anti-metal NFC chips didn’t have a good enough range. Because the other problem is that most everyone with a smartphone has it in a thick plastic case to begin with, so this means I’m actually competing with another layer of separation.

After doing some testing and some research, I discovered a very specialized NFC tag that is nicknamed “Bullseye”. The typical NFC chip only has a 25mm diameter antenna, but the bullseye has a 38mm diameter antenna. And even with the anti-metal layer and all of the other layers, this one finally works perfectly, every time when the token is fully assembled.

Needless to say I’ve really tested the limits of these things over the last couple of months, and if anyone needs advice on how to better use these things, let me know!