SnowShoe Stamps

Create magic with a touch of plastic

From the description of their product, you might think the team at SnowShoe has done the impossible. “SnowShoe Stamps are small pieces of plastic,” the company says. “They have no batteries, no power, no circuitry, no antenna, and no moving parts.” Yet each stamp “carries a secret digital identity.”

Touch a stamp to your smartphone or tablet screen, and the inanimate lump of plastic magically acts as a key -- to prove your identity, activate an app, or interact with a game or connected product. But the real key, it turns out, is not magic: it’s multi-touch.

Though the stamps don’t display any visible marks, just beneath the plastic veneer is a unique pattern that no other stamp shares. When pressed to the screen, it creates a multi-touch “signature” that lets an app know which stamp is which.

SnowShoe creates its stamps with a 3D printer, which allows for easy customization of hidden signatures. It also allows stamps to be printed in any form factor, from a traditional square “rubber stamp” shape to being integrated into the wildest-looking toys or peripherals.

Since the stamps are really just plastic (the same kind used in Legos, actually), they’re super cheap to manufacture. We have seen similar attempts at giving identity to simple 3d printed projects using NFC tags being directly added during the 3d printed process and using Terahertz imaging (See:InfraStructs).

Image Credits: Karl D.D. Willis and Andrew D. Wilson

Some possible uses for SnoeShoe stamps are: to enable tabletop games with a companion app; as initiators to other connected devices; or as physical keys for sensitive information, like BitCoin data. For some kinds of information, of course, privacy and security become a concern. SnowShoe uses the open security protocol OAuth to verify API calls, though data will still be shuffled back and forth between the user’s device, the client app’s own servers, and SnowShoe’s servers and API.

3d Printed Digital Identities: SnowShoe Stamps
3d Printed Digital Identities: SnowShoe Stamps

For developers, SnowShoe provides both stamps and software -- the “front end” that records multi-touch signatures, which will be integrated with other apps -- as well as a RESTful API that matches each signature with a particular stamp. Kits are free and come with two demo stamps. For full rollout, developers will either pay for small quantities of stamps (and receive some amount of API calls for free), or buy large number of stamps at a discount and pay a software licensing fee.

SnowShoe is a graduate of the Disney Accelerator program and in mid-October raised a $2.2M Seed round (led by FG Angels Syndicate, the AngelList Syndicate of Foundry Group) to scale the stamp's manufacturing. You can learn more about the company and the stamps at

Related: ThinFilm, InfraStructs: Fabricating Information Inside Physical Objects for Imaging in the Terahertz Region (PDF)


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