ضمنا اینم یه سنسور جیبی که کنار فلز یابتون میتونید استفاده کنید
ساختش
http://www.easytreasure.co.uk/probe.htmIt is an auxiliary, miniature metal detector, which can be used for precise location of small metal objects in the ground. Using this device, it is also possible to specify the location of metal pipes in the wall or reinforcement rods in the ceiling, which is important when drilling holes there.
Presented device has two coils: one is transmitter, the second is receiver. Their mutual positioning is such that to minimize the effect of transmitting on the receiving coil. Metal object, which is close to them, violates this balance, causing an increase of amplitude and phase shift of the transmitter signal, inducing in coil of the receiver.
This principle allows much greater ranges, as well as minimizing the impact of mineralization of soil on the detector work.
Basic features:
mode – static
frequency of 10kHz
ranges – 5cm (little coins) to more than 20cm (large objects)
does not respond to rocks containing iron compounds
low power consumption (9V – about 7mA)
a tiny plate (8,5cm x 1,7cm)
buzzer and LED (vibration can be also added)
the shape of the probe allowing the soil moving
low cost – built of readily available compounds
Photos:
http://www.edaboard.com/thread230880.html