Sensor coil

[sundar]

In the circuit attached what is the sensor coil (l1)and how can we make it.

 

[JimB]

Who knows?
What does the original write-up say?

Try 5 turns of 0.6mm hook-up wire wound into a 25mm diameter coil, stand it next to the cell phone and see what happens.

Why do you need this?
My cell phone which is "state of the ark" lights up its self on an incoming call, it also makes a noise.

JimB