A developer built the Muxcard, an experimental computer the size of a credit card, featuring NFC, sensors, Wi‑Fi/Bluetooth, and an E Ink screen.
A computer small enough to slide into your wallet is no longer a sci-fi promise; the new Muxcard prototype aims to make that idea real. using an e-ink display and everyday connectivity.. Built by a developer known on GitHub as “krauseler. ” the credit-card-thin device is positioned as a new kind of ultra-portable computing gadget. one that could blend into daily routines rather than demand attention like a phone or wearable.
The experimental system. described simply as the “Muxcard. ” packs a fully functional microcomputer into a form factor that’s roughly the same thickness as a standard bank card.. The device is reported to be just 1mm thick. with enough room inside a wallet-friendly package to include wireless capabilities. NFC support. multiple sensors. and an E Ink screen.
Despite the tiny body, the hardware choices are surprisingly complete.. The prototype is powered by an ESP32-C3 microcontroller and includes a 1.54-inch flexible E Ink display.. It also adds NFC hardware. an IMU motion sensor. and both Bluetooth and Wi‑Fi connectivity—features that together suggest the card can interact with nearby devices and systems without needing a bulky external setup.
The challenge wasn’t only fitting components into a smaller space; it was surviving real-world handling.. The project details indicate the creator had to make the electronics durable enough to withstand bending and pressure that come from being stored alongside other cards.. To reduce mechanical stress. flexible PCBs were used. and sensitive parts were separated into “islands” that are connected through bend-tolerant sections.
Integrating the E Ink display appears to have been one of the toughest engineering hurdles.. The creator reportedly faced connector constraints that were too bulky for the device’s thickness requirements. so the display flex cable was hand-soldered directly.. That kind of workaround underscores how compact designs can quickly turn into precision assembly problems.
Power management presented another major constraint.. With ultra-thin batteries comes very limited capacity, forcing tradeoffs in how long the device can function between charges.. In this design. the E Ink screen is especially relevant because it can display static information while consuming very little power compared with more power-hungry displays—an approach that could help the Muxcard remain usable despite a small battery.
What makes the prototype more than a maker novelty is the direction it hints at: invisible and ambient computing.. Instead of limiting compact devices to watches and phone accessories, the Muxcard pushes computing into objects people already carry.. In that sense. the project aligns with the broader idea of technology becoming background-friendly—present when needed. but unobtrusive in form.
The E Ink aspect also connects to practical use cases that benefit from low energy and readable, always-there displays.. The project description points toward possibilities such as secure identification. digital business cards. two-factor authentication systems. event passes. and minimalist smart home controls.. These are scenarios where a small display that sips power can be more useful than a high-refresh screen that drains a battery quickly.
On the development side, the Muxcard is positioned as an experimental open-source project rather than a commercial product.. The report states that the hardware files and firmware have already been published online for non-commercial use. enabling developers and enthusiasts to try building their own versions.
Looking ahead. the project’s long-term promise depends on continued progress in the underlying components—especially flexible electronics. thinner batteries. and even more efficient low-power displays.. If those building blocks improve as they evolve. concepts like the Muxcard could influence future digital IDs. more compact secure authentication tools. and new ultra-portable computing devices designed for everyday carry.
Muxcard E Ink computer ESP32-C3 NFC device ultra-portable computing flexible electronics digital authentication