You can use the audio duration to disc out large targets. A typical pop can will give an audio sound lasting 5 seconds, Beginning with the second HIGH-LOW or LOW-High. Now compare that to a coin sized object, which gives about a second of audio duration, again on that second beep.
Bobby pins are easy to also ID. Listen carefully for either a double beep or nulling when swinging over a target. If it nulls, try running the coil over the target from different directions to try and get tt to double beep. If it doesn't dig it, for it might be a chain. If it does double beep, chances are it's a bobby pin or nail. If you are still not sure, dig it anyway.....as it costs you nothing.
Bobby pins are easy to also ID. Listen carefully for either a double beep or nulling when swinging over a target. If it nulls, try running the coil over the target from different directions to try and get tt to double beep. If it doesn't dig it, for it might be a chain. If it does double beep, chances are it's a bobby pin or nail. If you are still not sure, dig it anyway.....as it costs you nothing.