I created a Laser piano using LDR and laser light diode. I used Arduino Leonardo Pro Micro connected to a speaker to generate sound. You can modify the tune of the piano by tweaking in the code and changing the frequency. I wanted to create something cool which can produce music and I ended up making this.

For this instructable you will need following components :

Arduino Leonardo Pro Micro - 1
10 K resistor array - 1
Laser diode - 8
LDR - 8
Speaker - 1
Cardboard
Gluegun
Soldering Gun
Nose Plier
Wire Stripper
Wire

Step 1: Video

Step 2: First Step : Marking, Cutting and Gluing Base

The base is made up of lot of cardboard ad glue gun. I have given the details along with the dimension in the image. Also make sure you are choosing the right kind of cardboard for making it.

In this step, we are going to cutout cardboard with the given dimension. we are using good quality cardboard to avoid any lose structure. Also make sure that you are ready with your glue gun.

Step 3: Second Step : Inserting and Attaching LDR and Laser Diode in the Cardboard

Simply insert LDR on the top holes of the structure. Leave some legs of LDR. Because this will help us to bend it and align it so the laser diode is pointing light towards the LDR. Then solder one end of all the LDR together. And solder 8 wires to 8 legs of LDR. We will use them as inputs to arduino. Then Solder the common anode and common cathode of Laser diode.

Step 4: Third Step : Making the Circuit

Finally make the circuit as per the given circuit diagram. Note that I have used a 10K resistor array instead of normal 10K resistor. If you don't have a resistor array, you can use normal resistor.