I built a robot a while ago that I control via the iPhone (video).
The robot connects to a WiFi hotspot and the iPhone 3Gs would connect to it via Safari and I'd control it from there. Now that I've upgraded to iPhone 4s, Safari simply won't connect to the IP address stating "Cannot open page".
I can't figure out why. Every other device in the house connects to the robot fine. How can I debug this?