For the people looking into a way to display stuff on your Esp32 projects with very little power consumption, there is no better alternative than an E-Ink (E-Paper) display, because this type of display keeps it's 'image' without any power, it only needs to be turned on whil updating, making it the king of power effecient displays, another big positive point that E-Ink displays have is readability, they usually have very high contrast (black and white) and very good resolution.

Because of how good E-Ink displays are, in today's article I introduce you to the new CrowPanel 5.79'' E-Paper kit from Elecrow, a compact yet powerful kit designed both for amateurs and professionals. Besides the excelent screen this kit also comes with an Esp32 S3 with 8MBs of Flash and PSRAM.

1 - Specifications

2 - Pins and other IO

The first time you try to code with the CrowPanel, you might be confused as to which component is attached to which pin. In the following image, that is available on Elecrow's store page, you can see a label of all of the connections:

But because the images on the store's page can be a little hard to read, I made a header file with all the usable pins of this kit, if you wish to use these definitions, all you have to do is create a file named 'crowpanelpins.h' in your source directory and paste the code below into it (click image to view and copy code):

One thing I like to do is to add the code below at the start of the setup function, with it, the power LED turns on almost as soon as the Esp gets power:

If you, like me, use VSCode and PlatformIO for Esp coding, you will need this custom 'platformio.ini' file:

3 - The Good

Excelent display, excelent micro controller, excelent build quality, it is actually hard to find a reason not to like this kit. The SD card reader for me is one of the best features, with it, you can save a lot more high-res images to display.

Besides what I stated before the other features of this kit that made me love it even more were the battery connector that let's you connect a coin battery to make a trully wireless display that can display stuff 24/7 for a long time without needing to be changed and the mounts on the back that let you make custom mounts for it.

4 - The Bad

The only 'problems' I found with this kit are the need to use a custom Platform IO configuration file, the lack of a backlight, which makes it very hard to read the contents of the display at night or in the dark, and there is only 12 pins empty, besides that there is nothing to complain about with this kit.

Of the 3 'problems' I stated before, the need of a backlight and having only 12 free pins, might not even affect you depending on your use case.

There is also two more things I would categorize as bad, but not bad about the kit but more about E-Ink displays in general, one being the SLOOOW refresh rate, we are talking about 1 to 2 seconds if the whole screen needs to be updated, and the fact that there is only two colors, there are 3 and 4 color E-Ink displays out there but for DIY projects the two color, black and white display is the most common.

5 - Use cases

This kit can be used on retail as a cheap wireless price tag that you can code to automatically update prices every day or after a specified ammount of time. On your home you can also connect the Esp32 on this kit to your Home Assistant server and control your smart home through it, but there are a lot more use cases to it.

As an example I coded a cryptocurrency ticker that gets the latest price of Bitcoin from CoinGecko and displays it on the screen along with a graph and the difference in percentage:

6 - Should you buy it?

If you need to make anything related to saving power and need a screen with good contrast where you won't be refreshing it's contents multiple times a second there is no better alternative than a E-Ink display and with this kit you won't miss anything, so yes, 100%.

If you like this kit but think it is too big, or you need a different size, Elecrow also offers kits of the following sizes:

• 1.54'', 152 by 152 pixels
• 2.13'', 122 by 250 pixels
• 2.9'', 128 by 296 pixels
• 3.7'', 240 by 416 pixels
• 4.2'', 400 by 300 pixels
• 5.79'', 272 by 792 pixels (the one being reviewed)

Just keep in mind that would also need to change the display library to match your kit, you can get it on any of the examples for your kit size in Elecrow's Github repo.

And that's all, thanks for reading and stay tuned for more tech insights and tutorials. Until next time, and keep exploring the world of tech!