Transform the SF Clipper Card Into a Wearable




About: Former product @ Google. I like to think.

Tired of bulking up your wallet with several different credit cards, id cards, and transit cards?

We found out a way to extract the key functional components from the Clipper Card, and mold it into a variety of wearable devices, including a small rubber plate, a waterproof aspirin band, and a breadboard bracelet.

Step 1: Required Materials

- Clipper Card

- 100% Acetone Nail Polish Remover (Amazon link)

- Glass Jar


- NFC Reader (Amazon link OR use Android phone)

- Sugru (Amazon link)

- Aspirin Band (Amazon link)

- Grid-Style PC Board (Amazon link)

- Extra wire

Step 2: Dissolve the Clipper Card in Acetone

Place the Clipper Card in a glass jar and submerge with 100% Acetone solution.

Leave the Clipper Card in the Acetone solution for 3-4 days, until the Clipper card is fully dissolved. There should be clear separation between the layers of the card.

Step 3: Isolate the NFC Chip and Antenna

After soaking the Clipper Card in the acetone solution, remove the NFC chip and attached wire from the rest of the plastic. Make sure not to sever the connection in the wire.

Step 4: Confirm the NFC Chip Is Still Functional

Before trying to modify the NFC chip and antenna (the antenna is the circular wire loop that connects to the chip), verify it's working. There are two ways to do this:

1. Use an Android phone with NFC capabilities to check if it's working. We used the NFC Tools Android app.

2. Purchase an NFC Tag Reader + Writer, powered via a USB port. We used the ACR122U USB NFC Tag Reader & Writer.

When testing the configuration, make sure to place the chip + antenna in a parallel plane to the NFC reader, just as if it were a full card.

Step 5: (Option 1) Embed the NFC Chip in Sugru

Sugru is a moldable glue that's commonly used in crafts (you can purchase it on Amazon here). Coil the NFC chip and antenna into a circular pattern such that it still triggers the NFC reader. Then, make any desired shape with Sugru that will fully encase the components.

Step 6: (Option 2) Encase the NFC Chip in a Waterproof Silicone Wristband

For a waterproof and durable wearable, purchase a waterproof silicone wristband.

Hollow out the inside of it a bit with some small scissors to make the hole a bit bigger, then insert the NFC chip and coiled antenna into the slot. Verify the end result works with an NFC reader.

Step 7: (Option 3) Fashion Your Own Bracelet

Alternatively, create your own bracelet with a minimized version of the NFC chip and antenna.

Coil the antenna wire around several times, to get the small, circular shape as shown above. Be careful not to sever the connection, as the wire is very delicate.

Then, secure the antenna and wire to a sturdy object. Get creative here! We used a flexible grid-style PC board with several holes. Generally, using things like glue or epoxy can help strengthen the connection.

After securing the antenna and wire, attach a string or shoelace to the object to wear on your wrist (or anywhere else you'd like!). You could also make it into a necklace, or stick the combined unit to the bottom of a watch face.

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    8 Discussions


    6 months ago

    From the Clipper cardholder agreement:

    "5.1 The Cardholder shall not alter or interfere with the graphic or data of the Card and shall take care to ensure that it is not interfered or tampered with. Cards that have been visibly altered will be considered damaged and not defective."

    I'm curious, did anyone have any issues getting through ticket check onboard the caltrain?


    1 year ago

    The silicon bracelet is so brilliant for kids. They lose a wallet a week and MTA makes it difficult to get kids' Clipper cards, so I'm SO making the kiddo one after I finish mine. Thank you!

    1 reply

    Reply 1 year ago

    Glad you enjoyed it :) Hope it goes well!


    2 years ago

    This is awesome! Maybe throw a top on your jar next time though :)

    2 replies

    Reply 2 years ago

    I put some seran wrap on top so that it wouldn't cast a shadow when filming the timelapse :)


    Reply 2 years ago

    oh well done, I didn't even notice. Surprising how much acetone evaporates despite that (I'm assuming its evaporating...)

    Anyways, this is really cool - I'm going to give it a go!


    2 years ago


    If you already have a wristwatch, you could probably also glue the chip onto the watch itself. I was thinking that since the silicone band is really small, it if falls off, you might not notice. If it's on a watch, you'd notice immediately.

    Or just embed it into your hand ;)


    2 years ago

    Those are all neat ways to make it wearable. I think the silicone bracelet would be the best just because I'm accident prone. XD