lightweight hardware to send a simple message to a .NET app via wifi : <p>If possible, could someone point me in the direction of some hardware which is capable of using a wifi signal to send a message to a .NET app, which could then pop a push notification on a mobile device? It would have to be a real-time thing, popping messages into a data table to be read when the app is launched will not serve the purpose I require it to, so the app would act constantly as a 'listener'. The contents of the message are not important (1 or 0 would do), what's more important is that the message is sent quickly and that the mobile device receives the message every time.</p>

<p>PS - cheap and lightweight is preferable of course!
Thanks in advance.</p>
