Repurposing an Old Phone: Personal HUD Screen

Instead of throwing away old hardware, why not put it to good use as a digital "picture frame" on your wall?

Published on . Takes about 5 minutes to read.

I was running with my buddy Priit, when I accidentally dropped my trusty Nexus 5 phone and cracked its screen. The screen had fractures, but was still perfectly legible; and the hardware still functioned. So, instead of throwing it away, I gave it a new life on my wall, as a personal “HUD” screen, showing relevant info such as weather, time and bus schedules.

Revision #1

The first revision was just a hacked-together .html page with some inline Javascript string concatenation. It fetched relevant data from publicly available API-s and displayed it out. The page took as little work as possible, to get the prototype usefulness validated.

As I was already running a in-home Openshift3 cluster, deploying it into a Nginx stateless web container was a non-issue and after two nights of hacking I had a functional prototype.


  • Display current time using moment.js
  • Show current weather and the forecast for the next three hours using data from OpenWeatherMap API
  • Show the departure times (using real-time GPS predictions) of busses from my nearest stop using the undocumented and quite horrible CSV “API” from Tallinn city
  • Always-on screen on dark background
Revision 1

The solution was quick to implement and worked; providing useful information when I was heading out. However, as quick PoC-s often do, it had its problems:

  • The codebase was a mess - literally hacked together into a couple of files. It needed refactoring and “beautification” before I dared show it to anyone
  • All config was hardcoded
  • It was not very modular nor expandable (with new features)
  • After a couple of months, I learned what screen burn-in means
Screen burn

Screen burn-in: the outlines of previous content are visibly “burned in”.

Revision #2

I was satisfied that the concept worked and provided value; time to refactor.

I ordered a cheap-ish, but still good quality (excellent, large screen!) tablet from China -Teclast T10. This gave me larger screen real-estate and also a better quality (and not broken) touch-screen.

I rewrote the code from zero and split the project into two parts: screen-frontend (Vue.js) and screen-backend (Python / Flask). This allowed me to do it in a API-first manner and also keep everything nice and apart.

Getting to know Vue and Webpack without prior major JavaScript experience was a challenge, especially the asset build process (I insist in using CoffeeScript and Sass over their ‘plainer’ cousins), but finally, I succeeded.

I removed most of the hardcoded values (weather station to use, bus stop ID-s) from the code, which makes it more portable and - in theory - allows others to benefit from the project, although this is not a goal in itself.

I switched to weather data provider to the national weather service, because they have local data (although in XML…) and audio reports.

Why would API respond with HTTP 404 for valid queries is beyond me. Whoever developed that endpoint owes me 30 minutes of lost time.

I solved the screen burn-in problem by keeping the screen OFF most of the time. The tablet turns the screen ON automatically for five minutes when the front-facing camera detects motion. This saves the screen, some power and also keeps the ambient light low at night. This can be done with the Fully kiosk browser.


  • Show current time
  • Show current weather + forecast for the next couple of days
  • Play weather forecast in audio form (audio provided by the national weather service)
  • Highlight and display weather alerts for my area, if there are any
  • Show bus schedule in real-time
  • Track investments
  • Turn screen ON only if motion is detected
Revision 2


Tentative future plans include refactoring the codebase some more (don’t look at my variable names…) and adding more features, for example a tab that shows readings from home IoT sensors.

As the tablet is running its original Chinese firmware, I don’t consider it a “trusted” device: it could be doing much more than only detect motion with its camera. Hence, I will either try to flash stock Android to it (tried once, failed, any links to tutorials for this specific model are appreciated) or more likely, use my PFSense & IoT WiFi to block its access to the outside Internet.

Skill Level-Ups

  • First contact with Vue.js, Webpack and with Javascript frontend frameworks in general
  • Python / Flask experience
  • Open source credz (both the backend and frontend are in GitHub)

The project can be seen and used from and the backend API is at