Rohit and Prasad's Paperd.ink Smart Display Gets a Holiday Upgrade with New Tricolor Merlot Edition

Engineering duo Rohit and Prasad have a surprise for the holiday season: two new models of their popular open source ePaper smart display modules, the paperd.ink Classic and tricolor Merlot.

Rohit and Prasad unveiled the original paperd.ink back in June 2021, offering an all-in-one design that packed an Espressif ESP32 microcontroller and battery into a 3D-printed case behind a 4.2" 400×300 monochrome ePaper display. The idea was to offer an easy development platform for less-obtrusive desktop smart displays — and the design was released under an open source license to encourage remixing and adaptation to other use-cases.

The project's initial attempts at crowdfunding fell short of the pair's goal, but the project was rescued by a grant from the not-for-profit FOSS United Foundation — founded in 2020 to promote free and open source hardware and software projects in in India. Since then, the team has been working to refine the design — and the result is the next-generation paperd.ink Classic and Merlot displays.

"Our two variants, Classic and Merlot, offer a monochrome and tricolor ePaper display, respectively, so you can choose the perfect display for your project," the pair explains. "Plus, every paperd.ink device comes with a battery and enclosure, so you can start building right away."

The paperd.ink Classic, as the name suggests, matches the specifications of the original: a 400×300 4.2" ePaper display with four levels of gray, one-second refresh or 0.5-second partial update speeds, and a deep sleep current of just 16µA on a timer wakeup or 1.4mA for button wakeups. The display, microcontroller, and 1.9Ah battery are enclosed in a black and white plastic housing, which includes access to a microSD slot for storage and a USB Type-C port for charging and programming. An internal buzzer provides audible alerts, too.

The new paperd.ink Merlot, meanwhile, adds a new dimension by switching to a three-color display: black, red, and the background white. The resolution remains the same, but there is a cost: refreshing the tricolor display takes a whopping 17 seconds, with a corresponding cost in battery life. The remaining specifications are unchanged between the two, bar a slight increase in deep sleep current to 17µA based on a timer wakeup.

The new displays are now available to order on paperd.ink at $89 for the Classic and $99 for the Merlot; the project's source files are available on GitHub under a reciprocal Creative Commons Attribution Share-Alike 4.0 license.