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This valentines we made this wooden Harp and used Laser and Light Dependent Resistors (LDR's) to play music. I will not be showing you how to make the wooden structure, but you can find the images with exact dimensions if you want to use them. I have used the code of Piano Stairs which I found in this instructable

Here is the list of items that you will require

1. Wooden structure of the harp

2. 12 - 3mm red/green laser dots

3. 5V power supply for the Laser

4. A Tah board (you can use any Arduino as well)

5. 12 - LDR and 12 -1K Resistors

6. A Raspberry Pi

7. Set of speakers

8. Play Dough (yay!!!)

9. Tools - soldering gun, scissors, wires, Tape, Glue gun, and prototyping circuit board.

Step 1: Now Go Make Your Harp

Use can use the above drawing to create your own harp

Step 2: Getting the Circuits Ready

To understand how LDRs work follow this Adafruit tutorial. Connect 6 LDR's with a 1K pull down resistor to one Tah board and 6 1K resistors to another Tah. On one side use the connector from the 5V adaptor to power up the lasers. Connect the lasers in series and stick them using play dough in the upper cavity in the harp.

Step 3: Align Lasers and Place LDRs

Along the slit in the central cavity align the lasers and place the LDR's appropriately. Use the 6 analog pins of the Tah as the input from the LDR's

The following sketch can be uploaded to the Tah boards and you are good to go here.

Step 4: Setup the Raspberry Pi

Clone this repo in the home directory of your raspberry pi.

Next lets make the launcher.sh file run on when the Raspberry Pi reboots. To do that lets change the permissions

on the launcher.sh

 chmod 755 launcher.sh

Now test it, by typing in:

sh launcher.sh

This should run your Python code. Add logs directory

cd
mkdir logs
sudo crontab -e

add the following line to the end of the file

@reboot sh /home/pi/harp/launcher.sh >/home/pi/logs/cronlog 2>&1

Then restart the Rabpberry Pi

sudo reboot
<p>This is great! I love the video of it in action! Do you think that there is any way to make this easier to play a tune on it?</p>
<p>you can change the .wav files in the sounds folder to whatever pleases you. Optionally you can add a smoke machine so that you can see the laser beams and then play the tune that you know the notes to.</p>

About This Instructable

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Bio: We are group of engineers who love to work on new ideas. We recently crowd sourced Tah a development board based on the Arduino.
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