You can hang on Door knob ( metal knob ), once someone touch the knob, alarm will loud. or you can apply to other application. Example : how to use below ( Ps : don't forget to supply 9VDC battery :=)))) )

Technical information:
   - 9VDC battery required.
   - Alarm ( by Buzzer )
   - Current consume 50mA.
   - Adjustable pot for sensitivity of touching.
   - Comes with the schematic.
   - PCB size 2.6" x 1.9"

Download User Manual