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<!doctype html><html lang=en-us><meta charset=utf-8><meta name=viewport content="width=device-width,initial-scale=1"><link href="data:image/x-icon;base64,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" rel=icon type=image/x-icon><title>Simple world clock with eInk display and Raspberry Pi Zero</title><meta name=description content="Our team is spread across the world, from the USA all the way to Australia, sohaving some sort of world clock makes sense."><link rel=alternate type=application/rss+xml title="Mitja Felicijan's posts" href=https://mitjafelicijan.com/index.xml><link rel=alternate type=application/rss+xml title="Mitja Felicijan's notes" href=https://mitjafelicijan.com/notes.xml><style>body{padding:1rem;max-width:760px;background:#fff;font-family:sans-serif;line-height:1.35rem;font-size:16px;margin:0 auto}hr{margin-block-start:1.5rem}h1,h2,h3{line-height:initial}h1{font-size:xx-large}footer{margin-block-start:2rem}cap{text-transform:capitalize}table{max-width:100%;width:100%;border-collapse:separate;border-spacing:2px;border:1px solid #000;border-left:1px solid #999;border-top:1px solid #999}blockquote{font-style:italic}table thead{background:#eee}ul.list li{padding:.2em 0}ul{line-height:1.4em}td,th{border:1px solid #000;padding:4px;border-right:1px solid #999;border-bottom:1px solid #999;text-align:left}pre{text-wrap:nowrap;overflow-x:auto;padding:0 1em;border:1px solid #dcdcdc}code{padding:0 3px;font-size:14px;border:0}pre code{line-height:1.3em}pre,code,pre *,code *{font-family:monospace}figure{margin-inline-start:0;margin-inline-end:0}figcaption{text-align:center}figcaption p{margin:.3em 0 0}img,video,audio{max-width:100%}header{display:flex;flex-direction:row;gap:3rem}nav{display:flex;gap:.75rem}nav.main{flex-grow:1}.pstatus-orange{background:gold}.pstatus-green{background:#9acd32}.pstatus-red{background:#cd5c5c}@media only screen and (max-width:600px){body{padding:15px}header{flex-direction:column;gap:1rem}a{word-wrap:break-word}}</style><header><nav class=main itemscope itemtype=http://schema.org/SiteNavigationElement role=toolbar><a href=/>Home</a>
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<a href=/index.xml target=_blank>RSS</a></nav></header><main role=main><article itemtype=http://schema.org/Article><h1 itemtype=headline>Simple world clock with eInk display and Raspberry Pi Zero</h1><p><cap>post</cap>, Jun 26, 2021 on <a href=https://mitjafelicijan.com>Mitja Felicijan's blog</a><div><p>Our team is spread across the world, from the USA all the way to Australia, so
having some sort of world clock makes sense.<p>Currently, I am using an extension for Gnome called <a href=https://extensions.gnome.org/extension/2657/timezones-extension/>Timezone
extension</a>,
and it serves the purpose quite well.<p>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.<p>A while ago I bought a small eInk display <a href="https://shop.pimoroni.com/products/inky-phat?variant=12549254217811">Inky
pHAT</a> and I
have a bunch of <a href=https://www.raspberrypi.org/products/raspberry-pi-zero/>Raspberry Pi's
Zero</a> lying around that
I really need to use.<figure><img src=/posts/world-clock/hardware.jpg alt="Inky pHAT, Raspberry Pi Zero"></figure><p>Since the Inky <a href="https://shop.pimoroni.com/products/inky-phat?variant=12549254217811">Inky
pHAT</a> is
essentially a HAT, it can easily be added on top of the <a href=https://www.raspberrypi.org/products/raspberry-pi-zero/>Raspberry Pi
Zero</a>.<p>First, I installed the necessary software on Raspberry Pi with <code>pip3 install inky</code>.<p>And then I created a file <code>clock.py</code> in home directory <code>/home/pi</code>.<pre tabindex=0 style=background-color:#fff><code><span style=display:flex><span><span style=color:green>#!/usr/bin/env python</span>
</span></span><span style=display:flex><span><span style=color:green># -*- coding: utf-8 -*-</span>
</span></span><span style=display:flex><span>
</span></span><span style=display:flex><span><span style=color:#00f>import</span> sys
</span></span><span style=display:flex><span><span style=color:#00f>import</span> os
</span></span><span style=display:flex><span><span style=color:#00f>from</span> inky.auto <span style=color:#00f>import</span> auto
</span></span><span style=display:flex><span><span style=color:#00f>from</span> PIL <span style=color:#00f>import</span> Image, ImageFont, ImageDraw
</span></span><span style=display:flex><span><span style=color:#00f>from</span> font_fredoka_one <span style=color:#00f>import</span> FredokaOne
</span></span><span style=display:flex><span>
</span></span><span style=display:flex><span>clocks = [
</span></span><span style=display:flex><span>  <span style=color:#a31515>&#39;America/New_York&#39;</span>,
</span></span><span style=display:flex><span>  <span style=color:#a31515>&#39;Europe/Ljubljana&#39;</span>,
</span></span><span style=display:flex><span>  <span style=color:#a31515>&#39;Australia/Brisbane&#39;</span>,
</span></span><span style=display:flex><span>]
</span></span><span style=display:flex><span>
</span></span><span style=display:flex><span>board = auto()
</span></span><span style=display:flex><span>board.set_border(board.WHITE)
</span></span><span style=display:flex><span>board.rotation = 90
</span></span><span style=display:flex><span>
</span></span><span style=display:flex><span>img = Image.new(<span style=color:#a31515>&#39;P&#39;</span>, (board.WIDTH, board.HEIGHT))
</span></span><span style=display:flex><span>draw = ImageDraw.Draw(img)
</span></span><span style=display:flex><span>
</span></span><span style=display:flex><span>big_font = ImageFont.truetype(FredokaOne, 18)
</span></span><span style=display:flex><span>small_font = ImageFont.truetype(FredokaOne, 13)
</span></span><span style=display:flex><span>
</span></span><span style=display:flex><span>x = board.WIDTH / 3
</span></span><span style=display:flex><span>y = board.HEIGHT / 3
</span></span><span style=display:flex><span>
</span></span><span style=display:flex><span>idx = 1
</span></span><span style=display:flex><span><span style=color:#00f>for</span> clock <span style=color:#00f>in</span> clocks:
</span></span><span style=display:flex><span>  ctime = os.popen(<span style=color:#a31515>&#39;TZ=&#34;</span><span style=color:#a31515>{}</span><span style=color:#a31515>&#34; date +&#34;</span><span style=color:#a31515>%a</span><span style=color:#a31515>,%H:%M&#34;&#39;</span>.format(clock))
</span></span><span style=display:flex><span>  ctime = ctime.read().strip().split(<span style=color:#a31515>&#39;,&#39;</span>)
</span></span><span style=display:flex><span>  city = clock.split(<span style=color:#a31515>&#39;/&#39;</span>)[1].replace(<span style=color:#a31515>&#39;_&#39;</span>, <span style=color:#a31515>&#39; &#39;</span>)
</span></span><span style=display:flex><span>
</span></span><span style=display:flex><span>  draw.text((15, (idx*y)-y+10), city, fill=board.BLACK, font=small_font)
</span></span><span style=display:flex><span>  draw.text((110, (idx*y)-y+7), str(ctime[0]), fill=board.BLACK, font=big_font)
</span></span><span style=display:flex><span>  draw.text((155, (idx*y)-y+7), str(ctime[1]), fill=board.BLACK, font=big_font)
</span></span><span style=display:flex><span>
</span></span><span style=display:flex><span>  idx += 1
</span></span><span style=display:flex><span>
</span></span><span style=display:flex><span>board.set_image(img)
</span></span><span style=display:flex><span>board.show()
</span></span></code></pre><p>And because eInk displays are rather slow to refresh and the clock requires
refreshing only once a minute, this can be done through cronjob.<p>Before we add this job to cron we need to make <code>clock.py</code> executable with <code>chmod +x clock.py</code>.<p>Then we add a cronjob with <code>crontab -e</code>.<pre><code>* * * * * /home/pi/clock.py
</code></pre><p>So, we end up with a result like this.<figure><img src=/posts/world-clock/world-clock.jpg alt="World Clock"></figure><p>And for the enclosure that can be 3D printed, but I haven't yet something like
this can be used.</p><iframe id=vs_iframe src="https://www.viewstl.com/?embedded&url=https%3A%2F%2Fmitjafelicijan.com%2Fposts%2Fworld-clock%2Fenclosure.stl&color=gray&bgcolor=white&edges=no&orientation=front&noborder=no" style=border:0;margin:0;width:100%;height:400px></iframe><p>You can download my <a href=/posts/world-clock/enclosure.stl>STL file for the enclosure
here</a>, 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.</div></article></main><section><hr><h2>Posts from blogs I follow around the net</h2><ul><li><a href=https://chotrin.org/writing/2023-10-20.html target=_blank rel=noopener>OpenBSD upgrade and fall things.</a><div>Been AFK for a bit. It's autumn and I upgraded this server to OpenBSD 7.4! — <a href=https://chotrin.org>chötrin's wiki.</a><li><a href=https://mirzapandzo.com/next-image-url-parameter-is-valid-but-upstream-response-is-invalid target=_blank rel=noopener>Next/Image "url" parameter is valid but upstream response is invalid</a><div>Getting "url" parameter is valid but upstream response is invalid error with Next/Image on WSL2 — <a href=https://mirzapandzo.com/>Mirza Pandzo's Blog</a><li><a href=https://drewdevault.com/2023/10/13/Going-off-script.html target=_blank rel=noopener>Going off-script</a><div>There is a phenomenon in society which I find quite bizarre. Upon our entry to
this mortal coil, we are endowed with self-awareness, agency, and free will.
Each of th… — <a href=https://drewdevault.com>Drew DeVault's blog</a><li><a href=https://solar.lowtechmagazine.com/2023/10/workshop-in-rotterdam-how-to-build-a-bike-generator/ target=_blank rel=noopener>Workshop in Rotterdam: How to Build a Bike Generator</a><div>Afbeelding: Low-tech Magazine workshop in Rotterdam, the Netherlands. Poster: Marie Verdeil. Image: Sara Vercauteren
The workshop takes place on behalf of the “Hou… — <a href=https://solar.lowtechmagazine.com/posts/>LOW←TECH MAGAZINE English</a><li><a href="http://offbeatpursuit.com:80/blog/?id=24" target=_blank rel=noopener>Printf debugging</a><div>tags:
plan9
There’s no shame in that. Yes, there is documentation, code to be
read, and debuggers to be used. But sometimes you just need to “see”
what is happening.
So… — <a href=http://offbeatpursuit.com:80/blog/>WLOG - blog</a><li><a href=https://neil.computer/notes/chart-of-accounts-for-startups-and-saas-companies/ target=_blank rel=noopener>Chart of Accounts for Startups and SaaS Companies</a><div>Accounting is fundamental to starting a business. You need to have a basic understanding of accounting principles and essential bookkeeping. I had to learn it. Ther… — <a href=https://neil.computer/>Neil Panchal</a><li><a href=https://journal.valeriansaliou.name/deploy-a-nomad-cluster-on-alpine-linux-with-vultr/ target=_blank rel=noopener>Deploy a Nomad Cluster on Alpine Linux with Vultr</a><div>After spending countless hours trying to understand how to deploy my apps on Kubernetes for the first time to host Mirage, an AI API service that I run, I ended up … — <a href=https://journal.valeriansaliou.name/>Valerian Saliou</a><li><a href=https://jcs.org/2023/10/17/wikipedia target=_blank rel=noopener>Wikipedia Reader 1.0 Released</a><div>Wikipedia Reader
1.0 has been released:
wikipedia-1.0.sit
(StuffIt 3 archive, includes
source code
and THINK C 5 project file)
SHA256: 360e12d064f6579695f1e627ce34cb2f0… — <a href=https://jcs.org/>joshua stein</a></ul><p><a href=https://git.sr.ht/~sircmpwn/openring>Generated with openring.</a></section><footer><hr><p><big><strong>Want to comment or have something to add?</strong></big><p>You can write me an email
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