Simple world clock with eInk display and Raspberry Pi Zero

Our team is spread across the world, from the USA all the way to Australia, so having some sort of world clock makes sense.

Currently, I am using an extension for Gnome called Timezone extension, and it serves the purpose quite well.

But I also have a bunch of electronics that I bought through the time, and I am not using any of them, and it's time to stop hording this stuff and use it in a project.

A while ago I bought a small eInk display Inky pHAT and I have a bunch of Raspberry Pi's Zero lying around that I really need to use.

Inky pHAT, Raspberry Pi Zero

Since the Inky Inky pHAT is essentially a HAT, it can easily be added on top of the Raspberry Pi Zero.

First, I installed the necessary software on Raspberry Pi with pip3 install inky.

And then I created a file clock.py in home directory /home/pi.

#!/usr/bin/env python
# -*- coding: utf-8 -*-

import sys
import os
from inky.auto import auto
from PIL import Image, ImageFont, ImageDraw
from font_fredoka_one import FredokaOne

clocks = [
  'America/New_York',
  'Europe/Ljubljana',
  'Australia/Brisbane',
]

board = auto()
board.set_border(board.WHITE)
board.rotation = 90

img = Image.new('P', (board.WIDTH, board.HEIGHT))
draw = ImageDraw.Draw(img)

big_font = ImageFont.truetype(FredokaOne, 18)
small_font = ImageFont.truetype(FredokaOne, 13)

x = board.WIDTH / 3
y = board.HEIGHT / 3

idx = 1
for clock in clocks:
  ctime = os.popen('TZ="{}" date +"%a,%H:%M"'.format(clock))
  ctime = ctime.read().strip().split(',')
  city = clock.split('/')[1].replace('_', ' ')

  draw.text((15, (idx*y)-y+10), city, fill=board.BLACK, font=small_font)
  draw.text((110, (idx*y)-y+7), str(ctime[0]), fill=board.BLACK, font=big_font)
  draw.text((155, (idx*y)-y+7), str(ctime[1]), fill=board.BLACK, font=big_font)

  idx += 1

board.set_image(img)
board.show()

And because eInk displays are rather slow to refresh and the clock requires refreshing only once a minute, this can be done through cronjob.

Before we add this job to cron we need to make clock.py executable with chmod +x clock.py.

Then we add a cronjob with crontab -e.

* * * * * /home/pi/clock.py

So, we end up with a result like this.

World Clock

And for the enclosure that can be 3D printed, but I haven't yet something like this can be used.

You can download my STL file for the enclosure here, but make sure that dimensions make sense and also opening for USB port should be added or just use a drill and some hot glue to make it stick in the enclosure.

➝ Get in contact with me via email.


Articles from blogs I follow around the net

My wish-list for the next YAML

YAML is both universally used, and universally reviled. It has a lot of problems, but it also is so useful in solving specific tasks that it’s hard to replace. Some new kids on the …

via Drew DeVault's blog July 28, 2021
Against essential and accidental complexity

In the classic 1986 essay, No Silver Bullet, Fred Brooks argued that there is, in some sense, not that much that can be done to improve programmer productivity. His line of reason…

via Dan Luu December 29, 2020

Generated by openring