Metal Object Contact Detection Method for AVR ATMEGA controller?

[Narendra1190]

Hi Geeks!
I am working on Linear Actuator which i made from Stepper motor with screw mechanism.I am using it to push the metal object.But i am wondering how can i come to know at when exact the linear actuator comes in contact with metal object so i can calculate the further linear push.I need simple contact detection method using ADC or closed circuit method.I am using AVR ATMEGA32 microcontroller. Help me.A picture to understand the problem is attached.Thanks in Advance.

 

[KlausST]

Hi,

the simplest method:
* One metal plate is connected to AVR_GND
* the other metal plate is connected with AVR_port, set up as input with pullup enabled.

Consider to use ESD protection.

Klaus