Raspberry Pi project ideas: e-ink calendar and clock

By Xuyun Zeng | June 27, 2022

Today, we’re taking a look at two really brilliant Raspberry Pi projects – an e-ink calendar and an e-ink clock!

E-paper calendar

Reddit user Beaverknighterino said he was “fascinated with E-paper projects so I finally decided to make one for my work calendar.”

The materials Beaverknighterino used are as such:

Waveshare 7.5” B/W 800×480 E-paper
Raspberry Pi Zero W
Xiaomi 10000mAH Power bank
IKEA HOVSTA Picture frame

Beaverknighterino mentioned that the project was made a bit more difficult. This is because the work calendar uses CalDAV and many open source libraries support Google or iCloud only.

As of now, the system currently only gets less than five days of battery life before it shuts down.

However, this is also the result of an unoptimized code, which Beaverknighterino says will be the target for improvement in the next iteration.

e-ink displays are very power efficient because most of the power consumption happens when you refresh the display with new content. Once you set the content, power consumption falls to zero.

The issue here is that the Pi Zero W is kept running in order to refresh the display after every meeting appointment and at midnight.

CLICK HERE: Raspberry Pi Zero 2 power optimization tips and tricks

e-Ink clock

Waveshare 2.13″ e-Ink display showing a clock and date . Photo from u/tttpp / reddit

Here’s another project that uses the Raspberry Pi Zero.

Unlike the calendar above that’s powered by a battery pack, this is powered by USB, so there’s no issue with battery life.

The discussion surrounding the clock is probably the most interesting. One pertinent question is whether an e-ink display is capable of showing seconds. Here’s an important video:

Inherent to the weakness of an e-ink display is its one-second refresh time. This makes it very disruptive if you had to refresh every second and might not be conducive.

But that’s the price for an ultra-efficient display.

Yet another interesting discussion is whether or not the Raspberry Pi Pico would be a good substitute for a Pi Zero. Especially given that it’s cheaper and much easier to find in stock.

The conclusion was that, yes, you could… but…

But the issue is that the Pico doesn’t have the same features of the Pi Zero.

Thus, you will need to add on a few modules — either a real time clock module or something that gives it internet access.

A mini RTC module for the Raspberry Pi, available from this link.

Not that the Pi Zero has a real time clock on board, but at least you get WiFi (with the Zero W variant). So, in essence, the Zero is overkill but it’s convenient.

u/tttpp has shared his code and instructions for the Waveshare 2.13″ display v2:

Install pi lite with no GUI on it
Install python3 and tmux on it using SSH
Follow all the instructions from here to install the libraries and examples to setup the e-ink display
Create a new folder in the folder you downloaded from waveshare (where the lib, examples, etc folders are) and copy my code there
Create a tmux session so that the script can run indefinitely in the background and start it with python3 (path to code) and exit the tmux session

Note: this code is specifically for a Waveshare 2.13 inch display V2. It is quite easy to switch out between versions, you just need to run each example until one works (that has the same resolution as the e-ink you have), I will make a proper tutorial and clean up the code soon.