user45659: Hello and a very good day.
I am currently doing my final year project which involving Arduino KY-031 Knock Sensor as my input signal and it is apparently a digital type of sensor. So, my question is can the digital signal be converted to analog signal ? 
The reason I need it to be analog signal because I wanted it to be classified into 3 type of stages (low,medium,high).
p/s: I am using Arduino Uno as my controller. 

user16085: You can create an analogue representation of any signal - but you can't add in information which wasn't previously there.  The KY-031 doesn't give you any more information than "knock" or "no knock", so there's no way to get further detail out of it.

45659: <p>Hello and a very good day.
I am currently doing my final year project which involving Arduino KY-031 Knock Sensor as my input signal and it is apparently a digital type of sensor. So, my question is can the digital signal be converted to analog signal ? </p>

<p>The reason I need it to be analog signal because I wanted it to be classified into 3 type of stages (low,medium,high).<br>
p/s: I am using Arduino Uno as my controller. </p>
 16085: <p>You can create an analogue representation of any signal - but you can't add in information which wasn't previously there.  The <a href="http://henrysbench.capnfatz.com/henrys-bench/arduino-sensors-and-input/keyes-ky-031-arduino-knock-impact-sensor-manual-and-tutorial/" rel="nofollow noreferrer">KY-031</a> doesn't give you any more information than "knock" or "no knock", so there's no way to get further detail out of it.</p>
