Credit card dimensions: This fully operational computer is also equipped with an e-ink display.

      A developer has created an exceptionally thin computer that is nearly the same size and thickness as a standard credit card, potentially leading to a new genre of ultra-portable computing devices.

      Named the “Muxcard,” this experimental gadget combines a fully operational microcomputer, wireless connectivity, NFC capabilities, sensors, and an E Ink display within a casing that is only 1mm thick—compact enough to sit alongside bank cards in a typical wallet. The project, developed by GitHub user “krauseler,” has rapidly attracted attention from the maker and hardware enthusiast communities for challenging the physical boundaries of compact electronics.

      A petite computer that fits in your wallet

      Despite its slender design, the Muxcard boasts surprisingly powerful hardware. The device is driven by an ESP32-C3 microcontroller and features a 1.54-inch flexible E Ink display, NFC technology, an IMU motion sensor, Bluetooth and Wi-Fi connectivity, along with a miniature lithium-polymer battery.

      The engineering challenge was not merely about miniaturizing components, but also about ensuring they could withstand everyday bending and pressure within a wallet. According to information shared online about the project, the creator utilized flexible PCBs and strategically placed sensitive components into “islands” linked through bend-resistant sections to minimize mechanical stress.

      One of the most significant challenges was integrating the E Ink display into such a slim device. The traditional connectors were reportedly too bulky, necessitating that the creator hand-solder connections directly onto the display's flex cable. Power management also became a critical issue because ultra-thin batteries have a very limited capacity.

      Why this matters beyond a DIY project

      At first glance, the Muxcard might appear to be a niche venture for hobbyists. However, the project signifies a broader trend toward invisible and ambient computing—where devices are shrinking, becoming thinner, and more seamlessly integrated into everyday items.

      The inclusion of an E Ink screen is especially significant as it consumes almost no power while displaying static information, enabling the card to remain operational for extended periods despite its small battery. This low-power design could render devices like this appropriate for secure identification, digital business cards, two-factor authentication systems, event passes, or minimalist smart home controls.

      For consumers, projects such as the Muxcard provide a preview of how future computing devices may evolve past phones and wearables into everyday objects people already carry.

      What lies ahead

      The Muxcard is still an experimental open-source project rather than a market-ready product. Nonetheless, the hardware files and firmware have already been made available online for non-commercial use, allowing developers and enthusiasts to try creating their own versions.

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