2 weeks ago

Inky wHAT review

This larger e-ink display offers more room for images and text

What’s a wHAT? A wide HAT, that’s what. The Inky wHAT’s 4.2-inch screen has 4.7 times the display area of the Inky pHAT, and 5.4 times the number of pixels. So it’s far better for displaying detailed images and longer text. A small female header on the rear breaks out ten GPIO pins, including I2C and SPI – handy for attaching sensors and other components.

Mounted display

We tested the black/red/white version (it’s also available in black/white). As the wHAT comes fully assembled, you just need to mount it on your Pi using the supplied metal stand-offs, and a GPIO header extender to boost the height for full-size Pi models. Care must be taken not to put too much force on the fragile glass screen, however.

A single command installs the Inky Python library and code examples, including a couple specifically for the larger screen. A famous quotes program shows how to reflow text to fit the display, while an image dithering script converts any picture by resizing and changing the colour palette; the latter works best with simple graphics – photos are still recognisable but a bit grainy. The clearest results come from creating your own images in GIMP, using an indexed colour palette.

It takes around 25 seconds to do a full screen refresh: there’s a fair bit of flickering, then the images gradually appear. So it’s only really suitable for projects needing an occasional screen update, but – as an e-ink display – only uses any power while refreshing.



Due to the lengthy screen refresh time, it’s not usable for every project. However, its larger display is ideal for a weather report, calendar, news headlines, or to-do list.