We’ve all been there. You’re all set for your big presentation: beautiful template, just the right amount of text, fancy graphics and that one perfectly timed star wipe for comedic effect. You’re just about to leave when you remember, that the world isn’t an Apple commercial. You pack the HDMI-VGA adapter and a second one for backup, your brand new absurdly expensive slide clicker, you make sure your presentations looks good on a 4:3 screen too and walk into the hall with the confidence of a Python developer, only to be greeted by a hard-wired Windows XP computer with Office 2007…

I won’t bother you with any more stories. Here’s what I want: I want to be able to walk around with a tablet in my hand, the presenter notes on it and generally run whatever I want on it without having to worry about compatibility ever again. Why? Mostly because it looks futuristic and cool.

Possible easy solutions

Let’s get some of the obvious solutions out of the way first:

  • Office365 PowerPoint broadcast: low quality, requires a good Internet connection on both sides, works only in PowerPoint
  • Windows 10 “Stream to this PC”: only works on Windows 10, requires a (compatible) Wi-Fi card in the target PC
  • Miracast/Chromecast/WhateverCast: rarely available, even if I had my own dongle it would still require messing with the projector


If you want to use this setup, here’s what you’ll need:

  • A rooted Android smartphone (that supports USB tethering)
  • A Windows (7 or above) laptop (a touch 2-in-1 is even better)
  • A USB cable for your phone

The virtual display

The trickiest part of this setup is the virtual display. I don’t want to stream my laptop’s display, because I want to have my presenter view on it. I want Windows to think there’s an actual extra physical monitor connected to it. This is something that is very hard to achieve, but luckily, some Windows driver magicians over at datronicsoft have already done that and packaged into a rather neat application called spacedesk.

After installing the spacedesk driver on the laptop, I can connect to it from any device on the network using one of several available viewers: Windows, Android, iOS and HTML5. I’m interested in the HTML5 one because it is as cross-platform as anything can possibly be.

The viewer

Spacedesk’s HTML5 viewer is normally available on their website, but for several reasons, I want to serve the files to the target computer myself. A quick CTRL+S gets me the page and all of its JS into a folder that I can serve with a simple web server on my phone.

Out-of-the-box, the viewer doesn’t support Mozilla Firefox for “performance reasons”, but in my testing, it works just fine and I still prefer a slow connection to no connection at all, so a simple search-and-replace on the source code gets rid of the browser checks:

sed -i 's/browser.name === "Firefox"/\0 \&\& false/' spacedesk.min.js

Some further modification was done to pre-populate the address field with the (static) address of the phone’s tethering interface.

A simple httpd from Busybox will suffice to serve the files from the phone and present them to the target computer.

The network


The proxy