Merlot is an open-source hardware tricolor wireless E-paper display

paperd.ink Merlot is a tricolor E-paper display with an open-source hardware control board based on ESP32 wireless SoC that is programmable with Arduino, MicroPython, or the ESP-IDF framework.

We first wrote about the paperd.ink 4.2-inch ESP32-based monochrome e-Paper display last year, but the company has now refined its design with the “paperd.ink Classic” replacing the 3D printed enclosure with a vacuum cast enclosure and adding a 1,900 mAh battery. They also launched a new model, the Merlot, based on the same design but with a display supporting three colors: black, white, and red.

Merlot specifications:

• Wireless module – ESP32-WROOM-32 module with ESP32 dual-core processor, 4 MB SPI flash, 2.4 GHz WiFi 4 & Bluetooth LE connectivity
• Storage – MicroSD card slot for storing images, files, etc
• Display – 4.2″ tricolor e-Paper display with 400 x 300 resolution; full refresh: ~ 17 seconds; partial update: also 17 seconds…
• USB – 1x USB Type-C port for charging and programming
• Expansion – 26-pin extension header with 8x GPIO, I2C, UART, SPI, ESP_EN pin to enable/disable ESP32 to lower power consumption, LDO_EN pin to essentially turn off the board.
• Debugging – Via USB Type-C port connected to CP2104 USB-UART chip
• Misc – 4x tactile buttons, piezo buzzer, reset button, charging LED
• Battery – 3.7V 1,900 mAh LiPo battery
• Power Supply – 5V via USB Type-C port, 2-pin battery connector plus battery charger circuit
• Power Consumption – <20uA in sleep mode
• Dimensions – PCB: 92.1 x 78.1 mm; enclosure is 98 x 82 x 16 mm
• Certifications – FCC/CE

If the refresh rate is more important than having the ability to display color, the Classic monochrome display will refresh much faster in about 1 second for the full screen and 0.5s for a partial refresh. The company provides an Arduino library and code samples such as Crypto tracker, Youtube stats, Calendar, etc… and KiCad hardware design files on GitHub, as well as documentation on their own website where you’ll also find basic Micropython samples.

Last time around, paperd.ink launched their display on Indiegogo, but the company is now selling the new Classic (monochrome) and Merlot (tricolor) E-paper display directly for $89 and $99 respectively.

Jean-Luc Aufranc (CNXSoft)

Jean-Luc started CNX Software in 2010 as a part-time endeavor, before quitting his job as a software engineering manager, and starting to write daily news, and reviews full time later in 2011.

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