Electronic ink is a familiar technology to everyday makers they are low-power displays that have great visibility in sunlight and preserve the displayed image even when unpowered. Common applications have been signage, e-readers, or simple project dashboards. The technology refreshes slowly so it's never been for fast updating user interfaces, up until recently the technology has been limited to monochrome with a single color, but no longer. Hey gang! Tim here at Core Electronics, and here are the inky impression seven-color electronic ink HATs. And today we're gonna set one up to run with a Raspberry Pi Single-Board Computer.

This is the inky impression 5.7-inch seven-color 600x448 pixel E-ink HAT. HAT just means hardware attached on top. It has four tactile buttons on the back as well as female GPIO connections making it fully compatible with a Raspberry Pi single-board computer. Pimoroni also has a 4-inch more-pixel-dense version available as well. Everything explained here is going to be applicable for both these screens. Now to be clear these screens can produce seven block colors blue, green, red, white, yellow, orange, and black. Inside these screens are thousands of tiny oil-filled bubbles which are filled with colorful charged particles depending on the current flowing above or below these oil bubbles, certain particles are drawn up or down, when the particles are drawn to the top of the oil-filled bubbles we can then see their color displayed on the E-ink screen.

Everything on the table before me is everything you need to set up your Pimoroni E-ink display naturally you're going to need that color inky impression screen, you're also going to need a Raspberry Pi setup to run as a desktop computer, if you need help with that we have a guide linked in the description. We are using a Raspberry Pi 4 Model-B but this can be used with all Raspberry Pi Single-Board Computers like the Raspberry Pi Zero you're also going to want a microSD with the latest Raspberry Pi OS and a small screwdriver to mount everything easily.

The organic step now is to get all this hardware connected up. Push the microSD card into the microSD card slot on the Raspberry Pi. During the installation process, I would recommend keeping on the screen protector that comes with the Pimoroni screen. The front panel is glass and can get scratched install the fasteners and add the extender riser header to the inky board, then press the Raspberry Pi into the Pimoroni board carefully by pressing evenly on all corners of the board, from here connect up your Raspberry Pi as a desktop computer and you'll be done with the hardware assembly.

If you want to install a Raspberry Pi Zero instead it won't require any standoffs or extra tall headers, this is particularly desirable if you're going for a height that is as sleek as possible. To make your life with this screen the best possible let's download the software that is already built by Pimoroni to support it. Open up a terminal window by clicking on the black button on the top left of the screen, once here type and enter the following or copy and paste it from the written article. If prompted press y and enter on your keyboard to install all the packages, install all the example scripts, and have SPI the connection method between these two boards, enabled. For troubleshooting tips and an alternative installation method come check out the written up guide linked down in the description.

So here's how to display a simple image with a file name art.jpg open up the terminal window by clicking on the black button on the top left of the screen like before with that open make sure you have an image called art.jpg in the home/Pi/pimoroni/inky/example/7color folder now we're gonna type and enter the two lines one by one the first line is going to focus the terminal to the location of the example python scripts and goes as such cd /home/Pi/Pimoroni/inky/examples/7color the second line is then going to summon the powers of the python programming language to run that image script and select the image named art.jpg note that different file formats or names are going to work too you just alter the second line appropriately.

As soon as you type enter onto that terminal command you're going to notice your screen go through a number of total page refreshes so that way it can get all those colored particles to where they need to be, this will take up to 15 seconds to complete no partial refreshing software with these screens yet when it comes to choosing images from my preliminary experiences with this display everything hand drawn looks fantastic particularly comic strip panels, watercolor paintings, and old school posters also look great along with most styles of brushwork painting.

I found older film photographs have increased dithering when compared to digitally captured photographs but both still look very sharp.

Before moving on, let's take a dive into this image.py script and alter the saturation of displayed images I'm going to right-click it and open it with Thonny IDE is just a python interpreter and you can use whichever one you'd like. Having done that we're going to look down just a little until you see the variable named saturation, the default value is 0.5 and you can adjust that value from 0 to 1. Play around with the saturation levels to get exactly what you want on your specific image. On the screen now is different saturation levels for the same image so you can get a feel for what adjusting this setting will do for you.

Once you've adjusted the saturation make sure to save that file it is good practice with these E-ink screens to clear them before displaying a different image this prevents ghosting. Pimoroni created a python script for us called clear.py which I'll show you how to run from the terminal now. The first line is exactly the same as before and the second one is going to alter only slightly to target the clear python script.

There are other great Pimoroni examples here too like the one for displaying a web page it can be run in a very similar way as before, this script will take a screenshot of the target website and then display it onto the electronic ink display. So here is the web page, type and enter the following into a new terminal window, almost exactly the same except we're adding on the HTML at the end then we're going to type the following.

And there you have it! This hello world website is displayed on our E-ink so if you can make a web page out of your project then you can show it easily on a seven-color E-ink electronic paper. So let's also take advantage of these buttons on the back side of the Pimoroni screen there is an example Pimoroni script called buttons.py which when run will print messages to the shell when certain buttons are pressed. I'll show you right now.

Well, that's good and all but let's actually get these buttons to do something more. Jumping back into the folder structure you can see I added a script called randomizer.py this is a remix of that original button script along with more images that you can see along here that I've labeled one to ten. On opening the script with Thonny IDE you can now see that it's designed to randomly display a new image from a collection of images all labeled from 1 through to 10 whenever any button is pressed on the side so let's run this script and press a button, it's running in the background and I'm going to press any of these buttons and just like that a new image come to life.

And there you go! To get this functionality easy and all the time you're going to want this python script to run on boot, I demonstrate exactly how to do this with crontab in the full write-up guide, and if you actually want this script it's going to be there too.

Here is my current application for this sweet display I've set up the Pimoroni E-ink display with a Raspberry Pi and tucked them both neatly inside this pretty picture frame whenever it's power cycled it's going to change what image is being displayed from a current list of around 10 options I can add to it and control directly what image goes into it hands-free and remotely via my phone as I provided the local network details and enabled SSH plus VNC currently I have it set so at midnight it power cycles so a new beautiful color electronic ink image to be surprised by for every day. Dive into the full ride up to see a step-by-step on exactly how I did this so jump there if you want and that's it for today if you have a specific image you'd like me to try out with this screen, write me a message down below I'll set it up and show you we are full-time makers and we're here to help so until next time stay cozy!