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How it works
Two pieces of technology, both of which have been around for years. Put together, they make a screen that runs on nothing.
Step by step
From your camera roll to your Cherikey
Download the app NFC E-Tag
Free on the App Store. No account, no subscription, no cloud upload — the photo goes straight from your phone to the keychain.
Pick and crop your photo
Choose any image from your camera roll. The app previews exactly how it will look on the colourful display, and lets you adjust brightness and contrast before you send it.
Add a caption, if you want one
A name, a date, three words. It's printed beneath the photo in the same e-ink.
Hold the Cherikey to your phone
Hold the Cherikey on top of the phone. The transfer takes a few seconds. You'll see the screen redraw. That's it — you can put your phone away.
The technology
Why there is no battery
Both halves of the answer are things your phone already does every day.
NFC supplies the power
The same technology that lets you tap to pay puts out a short-range electromagnetic field. A small antenna inside the Cherikey converts that field into just enough electricity to run the display controller — the same trick a contactless bank card uses. Your phone is the power supply, and it only has to be one for a few seconds.
E-ink holds the image with the power off
An e-ink screen is a layer of microcapsules holding coloured pigment. A voltage moves the pigment into position, and then it stays exactly where it is — physically, not electrically. Cut the power and the picture remains. That is why a Kindle lasts weeks, and why a Cherikey lasts indefinitely.
What it looks like
Vibrant, and a lot of detail
The app prepares your photo for the e-ink screen, which is why the result reads like a fine screen print rather than a low-resolution photo.
- Portraits and pets: high contrast, strong result
- Line art, logos and illustration: excellent
- Busy landscapes: crop in close for the best effect
- Preview in the app before you commit — change it as often as you like
Common questions
Does the image ever fade?
No. E-ink pigment is physically held in place, so there is nothing to fade. Leave it in a drawer for a year and it will look identical.
What if my phone has no NFC?
Every iPhone from the iPhone 7 onward has NFC. If you're not sure, the app tells you on first launch.
Can two people set the same keychain?
Yes. Any phone with the app can update any Cherikey it touches — there's no pairing or ownership lock.
Is it waterproof?
Splash-proof. Rain, a spilled drink and a wet coat pocket are all fine. Don't take it swimming.