Just to mention that in the doc you said :
//listen for the process to exit when the timeout has been reached
But you emit 'exit' and not 'exited' :)
And to mention that read event don't always occur ... But it seems unstable according to http://nodejs.org/docs/latest/api/fs.html#fs_fs_watch_filename_options_listener
well , the same for start event ... it's "start" and no "started" .... anyway very cool stuff !
Curently the "read" event gets issued multiple times, rather than once when an image has completed. There does seem to be a way to know an image has been taken and saved, since that is the only event that provides a file name.