DIY metal detector array (32 coils 1 meter wide)

1 meter wide metal detector array with 32 coils. I used two times an arduino mega and a uLCD43PT display from 4D systems, the detection circuit is very close to the coil and uses an LM339 comparator witch produces a series of pulses that are measured by the arduino . With the 32 coils I have a search resolution of 3 cm wide and 5 cm deep. Each coil has its own flap so it follows the surface very well and is waterresistant so you can also use it under water