Our schematic consists on 3 elements which are: Photoresistor (LDR), Piezo Buzzer, 1 – 10 kΩ. The LDR can be connected any way you want because doesn’t have polarity. For resistance you can use from 1 ...

When getting started with Arduino, ... Digital (pwm) pin D3 drives the piezo-buzzer through a PNP transistor, and the analog pin A0 takes care of the 10K ... pin D2 is for the infrared receiver module ...