The dimensions of a credit card: This completely operational computer also includes an e-ink display.

      A developer has designed an impressively thin computer that closely resembles the size and thickness of a typical credit card, potentially paving the way for a new class of ultra-portable computing gadgets.

      Named the “Muxcard,” this experimental device integrates a complete microcomputer, wireless connectivity, NFC capability, sensors, and an E Ink display within a casing that is merely 1mm thick—thin enough to easily fit alongside bank cards in a standard wallet. The project, initiated by GitHub user “krauseler,” has rapidly attracted attention from the maker and hardware enthusiast community for its advancement of compact electronic technology.

      A mini computer designed to fit in your wallet

      Despite its slim profile, the Muxcard is equipped with impressively capable hardware. It operates on an ESP32-C3 microcontroller and features a 1.54-inch flexible E Ink display, NFC technology, an IMU motion sensor, as well as Bluetooth and Wi-Fi capabilities, all powered by a small lithium-polymer battery.

      Muxcard krauseler/Github

      The engineering obstacle involved not merely downsizing components but ensuring their durability to withstand the everyday bending and pressure found in a wallet. As per the details shared online about the project, the creator utilized flexible PCBs and strategically arranged sensitive components into “islands” connected by bend-tolerant segments to minimize mechanical stress.

      One of the significant challenges was incorporating the E Ink display into such a slim device. Reportedly, traditional connectors were too bulky, compelling the creator to hand-solder connections directly onto the display's flex cable. Managing power also presented a considerable challenge due to the extremely limited capacity of ultra-thin batteries.

      Why this matters beyond a DIY project

      At first glance, the Muxcard might appear as a niche experiment for enthusiasts. However, the initiative highlights a larger trend toward invisible and ambient computing, which focuses on making devices smaller, thinner, and more seamlessly integrated into everyday items.

      Muxcard krauseler/Github

      The implementation of an E Ink screen is particularly significant since it consumes minimal power while displaying static information, allowing the card to function for extended periods despite its small battery. This low-power design could render similar devices suitable for secure identification, digital business cards, two-factor authentication systems, event passes, or minimalist smart home management.

      For consumers, innovations like the Muxcard provide a preview of how future computing devices may transition beyond traditional phones and wearables into commonplace objects that people carry daily.

      What comes next

      Currently, the Muxcard is an experimental open-source project rather than a commercial offering. However, the hardware files and firmware have already been made available online for non-commercial use, enabling developers and enthusiasts to attempt crafting their own versions.

      As flexible electronics, thin batteries, and low-power displays continue to advance, concepts like the Muxcard could eventually shape the future of digital IDs, secure authentication solutions, and ultra-portable computing devices.