I have been getting interested in using my tablet as a portable oscilloscope, for working on older cars and electronic hobby stuff, plus my new 10-inch Insignia would be useful. While researching oscilloscope boards for Android tablets, I noticed there were some home-made probe thingies that connect through the headphone jack. The problem is that the home-made probe uses a 4-pole headset plug to input the signal as a kind of audio signal, and it made me wonder what kind of hack the Nexus 7 2013 has. I think it's a standard 1/8-inch stereo headphone jack, but it could be for a headset, as my phone headset has a 2.3mm plug, not the standard 1/8 or 3.2mm, and I can't try it. In any case, has anyone used an oscilloscope adapter board for Android that works?