Barcode Epidemic

Work in Progress!

Playing the Game

Getting Started

Usually, everything will have already been set up. So to get everything working, the sequence of events will normally be along these lines:-

• Plug in the router and switch it on.
• Plug in the laptop (server) and switch it on.
• Plug in projector/tv screen, and connect laptop to it.
  • Test that in advance of any public event.
  • Not all TVs are friendly. Check the notes about the laptop you're planning to use - whether it has a DisplayPort (HP), HDMI port (Lenovo and others), or a VGA port (almost everything). Check carefully you have the right cable as they are similar! And verify that what you're plugging the cable into supports it and works...
• Check that laptop is joined to mrc_outbreaks network.
• Double click on Live Epidemic on the laptop
• Turn some tablets on. Check they join mrc_outbreaks network.
• Start scanning barcodes.

How The Game Works

• The game works in social events of maybe 30+ people, in a well bounded arena, with a big screen.
• Start it by giving one or two people in the crowd a barcode. (Seed infections).
• Tell them to go to "infection control" - the people with the tablets.
• The victim sees the infection controller and presents the barcode.
• We have run two variations of this game; one of the following will apply:-
  • The infection controller asks whether the victim is a member of the department, or a visitor. Later on, we look at the graphs to see whether infections spread differently within the two groups, or between them.
  • Alternatively, at the Centenary event, we allowed a vaccination probability, giving the victim immunity, and causing them to make no further contacts. The immunity would either be pre-defined (in which case the victim would know already), or their status could be determined by pointing the tablet mysteriously at them and pushing a button.
• The infection controller scans their barcode, then destroys it.
• The tablet tells the infection controller how many infections they should make.
• The infection controller scans a barcode for each of those new infections, and gives it to the victim.
• The victim is told to spread these infections to whoever they want. Tell each new victim to visit "infection control".
• The victim is told they are now immune to further infections. However, it's most fun to keep this fact secret.
• If the victim is given any more barcodes, they must accept them, but they shouldn't visit infection control again.
• Graphs and movies of the current epidemic will be shown in bright colours somewhere in the room.

The Parameters

• The tablets communicate with a web server; the dynamics of the epidemic can therefore be changed on-the-fly, without the infection controllers knowing about it.
• If appropriate for the game being played, the vaccination probability can be set.
• The number of contacts is assumed to be poisson distributed around a specified mean.
• However, in practise, we want to truncate the tail quite tightly, so there is a ceiling parameter.
• And in some cases, we wanted to ensure people made at least one contact, so there is a floor parameter too.
• These can be set by browsing to http://192.168.2.2/epi when connected to the mrc_outbreaks network.

Installation from Scratch

If something has gone wrong, or the Barcode Epidemic needs setting up on new equipment, then the following should be everything you need to know. I'll use the current equipment to describe the process; steps will differ with different equipment obviously, but the principles should still work!

The Web Server

We need to run a lightweight HTTP server that supports PHP. I like Abyss X1:- it's simple, very lightweight, and there are versions for all platforms. By all means, setup another web server if you prefer, but this one has served very well. Instructions below are for both Windows and Mac; if you use Linux, you'll probably figure out the very simple requirements. My instructions here are very simple - change locations to how you like if you're happy doing that.

Installing Web Server Software

• Download Abyss from here for your platform; Windows, Mac or Linux.
  • Windows: - I installed to C:\Abyss, for simplicity. I tell it to install as a Windows service, and have it start up automatically.
  • Mac: - I mounted the installer, dragged the Abyss Web Server folder into my Applications folder, then tried to run the Abyss Web Server app from new folder I'd just dragged. It complained at me because it didn't come from the App Store, so I had to use Control+Click to run the app, and confirm I knew what I was doing. Also on running the Web Server, it asked me to confirm I wanted it to Activate ports below 1024 - to which I said Yes, to make it run like a normal web server.
• Download PHP - Aprelium provide convenient downloads for Windows and Mac here. PHP 5 is fine.
  • Windows: - I installed into C:\Abyss\PHP5.
  • Mac: - again, I mounted the installer, and dragged the PHP5 folder into Applications.
• First-time the Server
  • All: - Open a browser and go to 127.0.0.1:9999. You should get the Abyss First-time Configuration page. Choose your Language (I'll be describing English!). Then choose a user and password, which is specific to managing Abyss. Make a note of it in whatever way you like, although you won't need it much.
  • Mac: - At this point, Safari got its knickers in a twist and I had to restart it, and browse to 127.0.0.1:9999 again. If nothing happens, do that.
  • All: - Your browser will now ask you for the user/password you chose.
• Configure for PHP
  • All: - In the middle, you'll see "Default Host Running on Port 80." Click Configure next to it, and then Scripting Parameters. Ensure Enable Scripts Execution is ticked, and Type is set to standard. Then under Interpreters, click Add, set Interface to FastCGI (Local - Pipes), and for Interpreter, you need to locate a file "php-cgi" - where you installed PHP. For Windows, something like C:\Abyss\PHP5\php-cgi.exe, for Mac: /Applications/PHP5/bin/php-cgi.
  • All: - Then in Associated Extension, click Add, and add the extension php. Click Ok, and Ok again.
  • All: - You should be back at the icons page. Go to Index Files, and add index.php. Ok, and ok again.
  • All: - And press the Restart button it is offering you. Wait a few seconds, and the config page will reappear. But you're all done now, so you can close it once it's done.
• The Content
  • In your browser, open 127.0.0.1 - without the :9999 this time. You should see the welcome screen.
  • That webpage on Windows is stored by default in C:\Abyss\htdocs; on Mac it's /Applications/Abyss Web Server/htdocs. We want to delete the contents of that folder, and replace it with the files needed to serve our epidemic purposes, in the next step.

Router and Wireless Connectivity

Using (for now!) The Belkin N750DB router. This router can't do DHCP reservations - it can't ensure that every time you connect to its wireless network with the same piece of equipment, you'll get the same IP address. This is exceedingly surprising and tedious, and this section will soon be replaced when we get a router that can do this simple task. In the meantime:-

• The Router
  • All it needs to do is create a wireless network for us. The Belkin is setup to provide a network called mrc_outbreaks, and dish out IP addresses in the form 192.168.2.x, where x>10. Use the WPS button on the router to share the password - I won't publish it here!
• The Server
  • Join the mrc_outbreaks network.
  • The router itself has IP 192.168.2.1. We want the web server to be 192.168.2.2.
  • Go to Control Panel, Network and Sharing Center, Change Adapter Settings, Wirless Network Connection (mrc_outbreaks), Properties, and Internet Protocol Version 4 (TCP/IPv4)
  • Make a note of the existing settings, as you'll need them to turn the laptop back to normal later.
  • Use the following IP Address: 192.168.2.2. Subnet mask 255.255.255.0. Gateway 192.168.2.1

The tablet

• Test by taking a tablet.
• Join the mrc_outbreaks.
• Browse to 192.168.2.2 to test it.
• You need two extra apps. Pic2shop does the barcode scanning for us, and there's the Live Epidemic app itself.
• To install these apps, I'm going to assume you've installed the Android tools, and the hack for the HP tablets described here.
• Connect a single tablet at a time to the laptop. In a command window, change directory to where you put your Android Development Tools (eg, cd \Program Files\Android).
• Then cd sdk/platform-tools. Might be a good idea to copy any apk files you want to install into that folder.
• adb install app.apk (where app.apk is the path to the package you want to install - pic2shop.apk or liveepi.apk)
• The apps will install.
• You might need to tell the Live Epi app where the web server is. Click the "three dots" icon in the top left corner, and set the website to http://192.168.2.2/epi/
• Then scan a barcode. If it appears to work, then it probably does!

The Live Display App

• Finally, we need to install the graph plotter software for the big screen. Firstly, unzip the content into a folder called "C:\Cent". (The name is a legacy from the MRC Centenary events by the way).
• Pre-requesties:-
  • You'll need a version of R installed. Add the statnet and animation packages in the normal way.
  • Unzip the ndtv package into the library folder, inside your R installation.
  • Install Java (JDK recommended) - any version 7 or later. Add the path to java.exe (C:\Program Files\Java\jdk1.8.0_05\bin) to the system path.
  • Install PDFtk Server - a commandline set of tools for mangling PDFs. As part of the install, say yes, it should add the bin folder to the system path. #
  • Install the dot matrix font, as the interface uses it to look, er, cool.
  • Install GhostScript.
  • Unzip the 64-bit VLC into C:\Program Files\VLC
  • Remember to start a new command window after changing the system path!
• The Content
  • Make a folder C:\Cent to put the content in - the name is a echo of the MRC Centenary events where all this began.
  • Edit run_r.bat and mm.bat and check that the path to your R installation is correct.