I had to keep the camera with one hand and work with the other one...i tried with the recorder mounted on a bike helmet, but it was too hard to control the image. The wire you see is for power supply the recorder, because the battery wasn't charged enough. I you know enough about electronics you can find this detector in a DIY kit at this link:
http://www.nuovaelettronica.it/prodotti/kit/strumenti-laboratorio/rivelatore-campi-magnetici-1-1310# (italian only). This is the low frequency detector, i also have the high frequency one! The unit is MICRO-TESLA, 20 for high sensibility and 200 for low. Let me know what you think!