Many users have issues connecting iPad to Barnacle's ad-hoc network. Here's some light as to why iPads are having difficulties when iPods and iPhones are doing fine.

The problem here is timing. Basically, the wireless driver on many Android phones only beacons an ad-hoc network for a while, and then if no other client associates, it stops. The next time it tries, it uses a different BSSID. Unfortunately, AFAIK, there's nothing we can do to stop it. If you try providing a BSSID in the settings, it might simply fail to beacon at all (it would only associate with an existing network matching that BSSID).

On the other hand it seems that the iPad won't beacon a network. It only wants to associate with an existing network and it does so by matching the BSSID after you tell it to connect. So you can see, there is a very short window from the moment your Droid starts beaconing to the moment it will inevitably change its BSSID. This short window is when your iPad can connect with it.

The known workaround right now is to first establish an ad-hoc network by other means and then tell an iPad to connect to it. For example, if you can connect your laptop to barnacle, you should then be able to connect iPad without issues. You can then turn your laptop off.