This board can detect any metal , coin , stainless any thing which was made by the metal, 1-5cm distance  for sensor to detect the metal depend on how big of metal, if it is small size, it can detect 1-2cm, example coin.

Technical information:
- Require Power Supply 9VDC  ( 9V battery )
- Current Consumption 40mA operate mode
- Adjustable the sensitivity to detect by POT
- Detection distance 1-5cm depend on size of metal
- Buzzer alarm and red LED turn on when sensor can detect the metal
- PCB size : 3.01" x 1.71"
- All module is tested again before shipping.
- Comes with the schematic.

Download User Manual