Text clock on a Raspberry Pi
Make your own text clock
Things you will need:
A Raspberry Pi
At least a Pi 3 A+. A tried it with a Zero, but it doesn't have enough grunt to handle the CSS animations. Anything beefier than a Model 3A+ would obviously work too, but the 3A+ is at the sweet spot for power-consumption versus performance (and price).
A 4x3 monitor
Ideally you'd want a fully-square one, but these seem to be few and far between - a search on eBay for "square monitor" yields a whole load of 4x3s claiming to be square, but 4x3 is close enough.
HDMI to whatever's on the monitor. The Model A has a full-size HDMI port, the Pi 4 has micro-HDMI, and the Zero has mini-HDMI. The monitor I got has a DVI port, and such cables are easy to come by.
This was all done on a pristine install of Raspberry Pi OS Lite (i.e. no
desktop) via the Raspberry
Pi Imager. As of this writing (2021-12-06) you should use the
Buster (Debian 10) distribution, which is tagged
(Legacy) in the Imager - there's a bug that stops
Chromium from starting properly in
Presuming you can SSH into the Pi:
(optionally) change the hostname:
sudo raspi-config nonint do_hostname jlock sudo reboot
Once you've done this you should be able to get to the Pi with
Git isn't installed out-of-the-box, so:
sudo apt -y update && sudo apt install -y git
Clone this repo
git clone https://github.com/pikesley/jlock cd jlock
And configure everything
This will install it all, and then reboot into a running clock.
Keeping it updated
jlock runs a cronjob
at 03:00 every morning to discover and apply updates to
does this via
git reset --hard origin/main so any local
changes will be blatted.
This was all developed on a Docker container. To run it:
git clone https://github.com/pikesley/jlock cd jlock ./configure make build make run
The container starts
nginx when you
connect to it, so it should be running at http://localhost:8080/. If you start the
then there should be a control interface at http://localhost:8000/controller/. Note that this interface is designed to run on a phone and the layout is not responsive, so you might want to open the inspector and set it to emulate a phone.
Install the node dev dependencies
and then run the tests (and the linters):
I wrote about my massively over-engineered design system here. To actually get the designs building, you'll need to get another connection to the container:
then start Sass:
(and there are also some Sass tests).
Push changes to the Pi
As long as
PIHOST in Makefile.common
resolves to the address of your Pi, you should be able to push new code to it
On the Pi, you can force the browser to reload with
DISPLAY=:0 xdotool key F5
- This was developed specifically on and for Chrome/Chromium. It works OK on Firefox and Safari, and it makes no sense at all on a portrait-orientated phone or tablet, but it was built to work as a kiosk app running on a Pi, which it does very well.
- For more about running a Pi in Kiosk Mode, see the
configure-shelltarget in this Makefile.
- There are some incredible people doing some amazing CSS text trickery.
- This owes a great debt to Carson Farmer's text-based clock, written in d3.js.
- Any similarity to a clock you can actually buy for thousands of pounds is entirely coincidental.