E-ink displays (also called e-paper) only need power when changing the image content. Therefore, the battery charges in eBook readers, for example, usually last for many weeks or even months. This 7.5 inch display by Waveshare even works without a battery or any other socket for power supply.
Nevertheless, of course, it takes a little bit of energy if you want to describe it in a new way. With this display, both data transmission and power supply take place wirelessly via near-field communication (Nearfield communication, NFC). So far, this technology has mostly been used to protect against theft or to pay by smartphone. However, many smartphones are able to transmit a certain amount of electrical power to NFC devices.
In order to be able to program the display with a smartphone, this power must be large enough. The manufacturer Waveshare points out that Samsung smartphones are not suitable. Appropriate Android and iOS apps are available for smartphones. With these, text and graphics can be created and transferred. As an alternative to the phone, the display is also available in a set with the ST25R3911B NFC programming device.
The display sits in a thin white plastic case (195.84mm × 137.68mm × 13.00mm). The resolution is 800 pixels x 480 pixels with a viewing angle of 170°. So far it is only available in black and white. It costs in the manufacturer shop 75 US-$ (standalone) or $104 (im Set with programmer).