why my ipod touch 4G won't detect another ipod touch 4G via bluetooth?

[Eduardo M]

My brother and I have an ipod touch 4G and we want to connect each device via bluetooth, the problem is that our ipods don't detect each other. I turned on the bluetooth and is searching, but it won't search for my brother's ipod. I tried with my cell phone and my ipod doesn't find the device either. Is there's another way to connect our ipods via bluetooth? Thanks