Soldered Electronics' New Inkplate 4 TEMPERA Upcycles an Unusual Square ePaper Display

Limited-edition new smart ePaper screen saves nearly 700 square-aspect E Ink displays from the scrapheap.

Soldered Electronics has launched a crowdfunding campaign for the latest in the Inkplate family of smart ePaper displays, the Inkplate 4 TEMPERA — offering Arduino and MicroPython compatibility, a built-in battery, and a 3.8" upcycled square-aspect E Ink touchscreen display.

Inkplate 4 TEMPERA is an easy-to-use, all-in-one device that puts the power of ePaper technology in the palm of your hand," the company claims of its latest product design. "Behind its 3.8-inch, 600×600-pixel ePaper touchscreen, it packs the following features into one compact, elegant package: frontlighting, an abundance of sensors, Wi-Fi and Bluetooth connectivity, a built-in battery, and a low-power operating mode."

The Inkplate family of smart ePaper displays grows again with the launch of the Inkplate 4 TEMPERA. (📹: Soldered Electronics)

The display in the Inkplate 4 TEMPERA is worth a second look: it's an unusual square aspect ratio with a 600×600 resolution, whereas most ePaper displays use a paper-like rectangular aspect ratio to better mimic books and magazines. They're also rare: "These ePaper screens were originally made by the E Ink Corporation for a now-discontinued product," Soldered explains, "and are available in limited quantities."

How limited? Soldered says it has just 370 with a glass panel and a further 300 with the bare screen protected by a plastic cover, all "rescued from a tragic future as e-waste." Both models include touchscreen functionality and a front lighting system for viewing in darkness, and are driven by a custom board based on an Espressif ESP32 microcontroller and with Wi-Fi and Bluetooth connectivity, microSD storage, a Broadcom APDS-9960 gesture, proximity, and light sensor, an LSM6DS3 gyroscope and accelerometer, a Bosch Sensortec BME688 air quality and environmental sensor, and a buzzer.

On the software side, the Inkplate 4 TEMPERA shares a socket stack with Soldered's previous Inkplate models, coming with out-of-the-box support for Arduino and MicroPython and community support for the ESPHome firmware. The device also includes a "Peripheral Mode," which accepts commands from external devices over a UART bus to update its display.

The built-in battery, meanwhile, offers a 1.2Ah capacity and links to charging circuit with fuel gauge. Exact battery life will depend on how much time the radio spends connected to a network and how often the display is refreshed, with Soldered claiming a 18µA current draw while running in low-power mode.

The Inkplate 4 TEMPERA is now available to back on Crowd Supply, priced at $149 with plastic cover or $169 for the version with a glass panel; both models are expected to ship in March next year, Soldered has confirmed.

Gareth Halfacree
Freelance journalist, technical author, hacker, tinkerer, erstwhile sysadmin. For hire:
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