NFC Keychain

Near-field communication (NFC) is a set of communication protocols that enables communication between two electronic devices over a distance of 4 cm or less.

I wanted to play a bit with NFC chips. The startup I work for was rebranding, so I offered to make a small keychain with NFC inside, which would redirect to their website. Nothing big, I thought it would be fun to do.

NFC Chip

I used this model and added the company’s logo. Getting the image to work in MakerLab was a pain, it did not load properly or at all. After googling, I tried recoloring and changing the file’s format, and it finally worked as a .webp with inverted colors.

Makerlab app

To print that model, I used a set of settings called ironing. It uses the hot end of the printer just like a smoothing iron. That setting is tricky, the results depend on the filament and on how precise the top layer needs to be. I had to try a few variations before getting something acceptable. Without ironing, you can clearly see the layer lines on the surface.

Inside the model, I added the NFC chip into a slot made for it.

3D Bambulab software

Here’s the result of the first test:

Next, I needed to write data to the chip. I used the app NFCTools. In “Write”, I added the company’s URL and tried to transfer it, but nothing worked. It worked once or twice randomly, and I couldn’t figure out why. Were the chips defective?

After about 15 minutes of searching, I learned that metal nearby can interfere with NFC writing. That’s when it clicked: my desk is made of metal. I stood up, tried again, and it worked perfectly. Now the keychain triggers the company’s website as soon as you tap it on your phone.

NFC Tools

There were still some small holes in the print, so I decided to use epoxy resin. We get the resin, weigh it like a physicist, mix mix mix, pour, dry, and… Woops! Two of the keychains touched, they’re a little quacked up. A few hours go by, I come check on it, but with my big fat thumb, I touch one, marking it forever with my fingerprint. Eh. Well, it’s still good enough for now.

Epoxy resin gives a clear coat, and I also use it to make prints watertight or food safe.

I brought the three keychains to work. I showed them to someone from marketing, and she asked if I could make more for the branding reveal event.

Challenge accepted, let’s print more!

In the image below, you can see where I paused the print to insert the NFC chips mid-print.

The result wasn’t great, there was some smearing of the color black. I sanded them for about an hour to remove the excess color and used lacquer to brighten the color and make them ✨shine✨.

Annnd here’s the final result!