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BrachistaLog is a small hardware company in Tokyo and Bangkok. We design devices that run without a battery, powered by the phone already in your hand. Our first product is LogCase, an iPhone case with an E-Paper display on the back.
Where the name comes from
A brachistochrone is the curve of fastest descent: the path a ball should roll along to get from one point to another in the shortest time. Surprisingly, it is not the straight line. We took the idea as our mission: the most direct path from an idea to something you can hold.
What we make
LogCase shows a picture of your choice on the back of your iPhone. Pick an image in the LogCase app and cast it to the case. Your iPhone sends the picture and a little energy over NFC, and the E-Paper panel keeps it with no power at all, for as long as you like.
There are three versions. LogCase -C and LogCase -R use a four-colour panel with a warm, sepia-like tone. LogCase Full Colour uses a six-colour panel for richer pictures.
No battery, by design
Refreshing a full-colour E-Paper panel takes more energy than a phone usually hands over NFC. We found a way to gather and spend that energy so the case needs no battery, and we patented it. With no battery inside, there is nothing to charge and nothing to wear out. To learn how the display itself works, read Understanding E-Paper.
Our story so far
- December 2024. BrachistaLog is founded in Tokyo and Bangkok.
- March 2025. The first LogCase, for iPhone 16 Pro and Pro Max.
- December 2025. LogCase in four colours for iPhone 17 Pro and Pro Max, with a sharper display.
- January 2026. We refresh a full-colour E-Paper panel without a battery for the first time.
- March 2026. LogCase Full Colour launches on Kickstarter. Thank you to every backer.
Two cities, one team
Our headquarters is in Tokyo, and our operations hub is in Bangkok, where orders are packed and shipped worldwide. The two cities are about 4,600 km apart, and we work as one team across both.
Build with us
The same technology can power other things that should show information without a battery. If you are stuck on an E-Paper problem, planning a product of your own, or would like to sell a full-colour case under your brand, talk to us.
Stay in touch
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