RohanHawthorne wrote: I think this would be possible by creating a website on the Pi, a wireless network from the Pi, and connecting to the website via the phones.
This part is very easy, just install Apache and PHP controls and write a series of HTML pages (a home page + one page per judge would probably be best). You can use wiringPi to have PHP commands from the webpage to directly control the GPIO.
Install wiringPi, Apache, PHP
$ sudo apt-get update
$ sudo apt-get upgrade
$ git clone git://git.drogon.net/wiringPi
$ sudo apt-get install apache2
$ sudo apt-get install php5
I followed this instructable
for making my webserver.
Building Management Systems Engineer.