this arduino module and lcd will give you a vdi reading of up to 90 which would indicate a quarter or above conductive target. The vdi i set to foil using your discrimination control and after that your ready to go. The IDX is a nice detector but was not a fan of the block type target id on it... The vdi is very accurate and also has a digital audio output that gives a higher tone the more conductive the target is. The volume of the audio can be controlled with a simple trim pot. The other trimmer is to adjust the contrast but that can be taken out and replaced with a resistor if the user desires. The Arduino measure 3" x 2" and can be installed in a small electronic project box or whatever you like, It can be powered with a 9 volt however a small 9volt pack rechargeable gives more run time.. The connection points will be marked legibly printed schematic that comes with the module. It reads penny,foil, iron,pulltab,dime,quarter penny etc for the target.. Thanks and email with any questions.. $60 shipped to the lower 48, paypal friends and family or whichever is good for you.