E-ink display with driver

Question

I want to buy an e-ink display (4 inches or more) that could be driven by RPi3. I need to show on display a simple web app written in Django (a to do list with a minimal design) which not required an high refresh rate. Unfortunately I'm not so expert about electronic and I ‘m not able to write a code to drive the display, so I don't know exactly what to look for. I think that the best solution is buy a display with driver board. In short, I'm wondering if exists an e-ink display which can be connected in a simple to RPi3 with driver included and which can show my web app. I want spend less 100$. I see PaPiRus ePaper but it’s to small for my purpose.

Thanks. (Sorry for my bad English)

Answer 1

All the eInk display avaliable that I'm aware of don't come with a "plug-in" device driver like a graphics driver. Instead, you get some low-level python driver that can transfer an python array to the eInk controller chip. There's no framebuffer driver that I'm aware of, which does make sense, due to the low update speed of eInk. You'll need to use some existing python libraries for rendering into a "bitmap" array, and then transfer that to the display. There is no simple plug and play or Linux framebuffer support (yet).

Maybe it's better to get a Rakuten Kobo ebook reader that is quite hackable software-wise, uses Linux, and has a framebuffer driver for its eInk display. But maybe this is just to crazy...

Answer 2

Amazon has many e-ink displays for under $100. I am going to order a Waveshare 4.2" display with a resolution of 400 x 300 pixels. I chose this product because it has an SPI interface and it says it has example software for the Raspberry Pi. I could have chosen a 7" display.

This display, like most e-ink displays are black and white (and red in the case of the module I ordered), without grayscale. I did see one display that had four levels of grayscale, but I wasn't as confident of the interface. This means that you'd have to avoid web pages that have fancy graphics.

I don't know if they have a driver that would allow this display to be used like a monitor. If not, you'd have to use modify a web browser to buffer the image, modify the image to be a true black/white image, then show that image through the SPI interface to the e-ink display. There is a simple web browser written in python that you could modify if necessary.

The other problem for using this as an interactive display is that it doesn't have a touch screen. I don't know how well a mouse can be displayed on it, even if there is a device driver that would allow it to be used as a monitor.

E-ink displays are great for uses where you have something specific to display that doesn't change often and you need something that has a low power requirement. They have a low refresh rate and they are more expensive that a more capable traditional display would be.