The Matrix uses Bonjour to establish a connection via either wifi or Bluetooth. If wifi is available and Bluetooth is not, it will automatically use wifi. If Bluetooth is available and wifi is not, it will automatically use Bluetooth. However if both are available it doesn’t seem to work very good. Bluetooth and wifi use similar frequencies and seem to interfere with each other. If you are having a problem with your connection, that most likely is the cause.
If you want to connect via wifi, turn off Bluetooth.
If you want to connect via Bluetooth, turn off wifi.
Both Bluetooth and wifi can be turned on or off in the Settings app under General.
The Matrix does not use the internet so any wireless router will work by just plugging it in (and setting it up correctly). You do not have to be on a wifi network that is connected to the internet.
However, if you are attempting to connect over wifi, you will need a connection that allows networking between devices -- which basically rules out any public wifi options. McDonald’s, Starbucks, Panera, etc, unfortunately all disallow this type of networking for security reasons. So just use Bluetooth instead (and turn off wifi).
If you are attempting to connect over Bluetooth you just have to be sure that Bluetooth is on and wifi is off for all of your iPads. All iPads have Bluetooth capability built in and are capable of connecting without any additional hardware or signal or anything else.
If an iPad is still having a hard time connecting, try toggling its listening button on and off. That gives it a fresh start.
When all else fails, reboot your iPad. I had an issue where Bluetooth wasn’t working no matter what, but then I rebooted and it was fine. To reboot, hold down the sleep button (the one on the top edge) and then slide to power off.