We present a new method (BUBBLY) for detecting expanding components of ionized gas using integral field spectroscopy, showing its capabilities not only in detecting but also in obtaining the key physical parameters of the detected expanding shells, notably their expansion velocities and their masses. The main advantages of this method are that the detection is performed automatically via software and that we can use it to obtain nearly all the parameters of the shells, which makes it suitable for detailed studies of feedback in nearby galaxies. The software can be easily configured to run on any data cube mapping an emission line over a spatial field.We also present a variety of results obtained by running BUBBLY on observations of Ha emission with the Fabry-Perot spectrograph GHaFaS, focusing on two sets of particularly spectacular results at widely different spatial scales: the Antennae galaxies show the presence of multiple giant bubbles of size ~300pc around the brightest clusters, while inside a region in M33 we find three nested supernova remnants, which we can use to study the effects of feedback on the molecular gas surrounding the cluster.