Seeed Studio’s e-paper kits integrate microcontrollers, displays drivers and battery-powered operation, supporting local image updates and smart home information displays.
Seeed Studio has launched two e-paper display kits preloaded with OpenDisplay, an open-source firmware and communication standard designed to send images to compatible screens. The kits consist of two displays: one monochromatic of size 4.26 inches and another color display of size 7.3 inches. Both display kits run on Nordic Semiconductor’s nRF52840 microcontroller. OpenDisplay is another way of managing display screens as opposed to using proprietary display screens because the OpenDisplay system will allow a device to be sent images over BLE or Wi-Fi depending on the hardware used.
The 4.26 inch monochrome kit features a 800×480 pixel resolution display which allows black-and-white output, as well as a 4 level grayscale option. Partial screen refresh can be carried out when in black-and-white mode. The larger 7.3-inch color kit uses a Spectra 6 e-paper panel with the same resolution and displays six colours: black, white, yellow, red, blue and green. Images are converted into this fixed colour palette through dithering. Both modules use specific Seeed XIAO e-paper drivers, featuring the nRF52840, which integrates a 64MHz Arm Cortex-M4F processor, 256KB SRAM and 1MB flash.
OpenDisplay allows users to send images through a web browser using its Toolbox, with Chrome and Edge supporting the required Web Bluetooth functionality. The firmware can also receive images from compatible applications and Python-based tools. The display units can be connected to Home Assistant to display information related to the weather forecast, temperature, energy usage, and calendar events. While the 4.26-inch unit uses BLE communication without any need for Wi-Fi. This local communication approach avoids depending on a remote cloud service to update screen content.
Both development kits have an inbuilt rechargeable 2,000mAh battery, USB type C charging capabilities, three control buttons, and 3D printed housing. According to Seeed, the battery life of the monochrome display is expected to be two years when it updates every 15 minutes, whereas that of the colour display is estimated to be one year when it updates every two hours. Depending on the update rate and environmental conditions, both battery life spans will vary. The monochrome display is capable of partial refreshing whereas the colour display cannot do that.
The OpenDisplay firmware, browser interfaces, Python API, and Home Assistant support can be acquired from the open-source community associated with the project. This enables users to create custom information displays and integrate the compatible e-paper displays into their applications without having to write the entire communication protocol. But the availability of open-source firmware does not mean that the display hardware itself is also open source. The Seeed Studio OpenDisplay 4.26 inch Mono Kit can be purchased for $39.90, whereas the 7.3 inch Color Kit costs $75.90.
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