How come my iphone is connecting to my Wi-Fi?

I have an iphone 4 and my computer and ps3 my nook connect to it fine. The iphone can still connect to wife's like at starbucks or a hotel but why not at my house

Added (1). I meant to say isn't instead of is in the question sorry

When my boss originally had trouble connecting his 4S to our office Wi-Fi I check Apple forums for help and discovered that iPhones are notorious for software and hardware Wi-Fi issues. At that time his phone needed an iOS update, but refused to do that on mobile data. Fortunately he got it to connect to his home Wi-Fi, updated his iOS, and then it was able to connect to our office Wi-Fi. We had the same issue with 3 iPads, they would not connect to our office Wi-Fi until their iOS was updated elsewhere that worked with Apple's broken Wi-Fi.

Fast forward a month or so and suddenly he could not even turn on Wi-Fi on his 4S, it remained OFF and grayed out (hardware issue). He had to get a warranty replacement 4S.

But it could just be that whatever Apple does differently with its Wi-Fi than anyone else is incompatible with your home Wi-Fi router. But I don't know what to check for to find one that is compatible with Apple devices.

Between 2% and 5% of router/device combinations (based on my experiences at home and with friends) are not fully compatible. At one end of the spectrum, the device simply does not detect the network at all. At the other end it can have a very slow connection.

You might have to add a wireless access point (of a different make from your router) to your home network and set up a second Wi-Fi network just for your phone.