Creative toys: laser harp

At the Iranian Pavilion of the Shanghai World Expo, I saw a harp without strings, which is the most interesting exhibit in the Iranian Pavilion recognized by many visitors! As soon as the visitor reaches through the black harp, the tone will be "played." How can no strings play? The staff revealed the secret for us - he pressed the "light" button on the piano and 14 red laser beams were emitted from the top of the piano. He said this is a laser harp. We use the fingers to “poke” the laser beam and the harp will sound, each beam having a different pitch. It is said that this harp was originally placed in Iran's Science Museum, mainly to arouse children's interest in music and technology.
This laser harp also reminded me of many old things. I told my classmates long ago that I could also make a laser harp and bet against him. It was only because of the problem of time that it had not been completed. Having read the laser harp of the Iranian Pavilion, I decided to make it, of course, a very simple laser harp. However, for friends who like DIY, it is also a good creative production.

Make necessary materials (see the attached table)



List of components using the AT89C2051 program



No. Part Name Quantity



1 12MHz crystal oscillator 1

210kΩ resistor 6

3 10μF capacitor 1

420 pin socket 1

5AT89C2051 1

6 Passive Buzzer 1

7 8550PNP Transistor 1

8 1kΩ resistor 1

9 Photoresistance 5

10 3V Laser Tube 5

11 Battery Box 1

12 Wooden Blocks 3

13 pins, sockets

14 copper seats, screws

15 Hole plate 1

Electronic Component:Tenco