You will need to connect the ground of your circuit to the arduino ground.
You may also need a resistor across the output as with no resistor the voltage on C5 will no fall when the input falls. You will need to set a time constant suitable for the signal.

 

Hello sir can i use AD620 in place of INA106?

How to make a dual voltage supply?

Please tell me about the supply for AD620 and the ground