This p oelectric piano has a total of 7 strings, and the buzzer emits the corresponding sound level when cutting the strings. Equipped with LED lights, the corresponding LED lights up when cutting the strings, totaling 7 LEDs. Optoelectronic pianos do not have strings, but are replaced by bright of light. Users only need to pluck , as if plucking the strings, and can still play a melody. This production consists of two parts: a p osensitive circuit and a microcontroller. It can arouse interest in music and technology, and for friends who enjoy DIY, this is a good small production. I used to see a harp without strings, which is widely recognized by many visitors as the most interesting exhibit in the Pavilion! Visitors only need to reach out and pass through the black harp, and the tone be played. How can it play without strings? The staff revealed to us - he pressed the "light" button on the piano, and 14 red laser s out from the top of the piano. He said, this is a laser harp. We use our fingers to flick the laser beam, and the harp make a sound, with each beam having a different pitch. It is said that this harp was originally placed in a in , mainly to arouse children's interest in music and technology. For friends who enjoy DIY, this is a good mini production. Power supply voltage: DC4.5V-5.5V. LED lights: 8. Power socket: DC-005 socket. Power cord: USB to DC-005 cable. Main board circuit board size: 8.9cm x 6.0cm. The principle of a string less qin (p oelectric qin): P oelectric pianos do not have strings, but are replaced by bright of light. Users only need to pluck , just like plucking the strings, and can still play a melody. This production consists of two parts: a p osensitive circuit and a microcontroller. When the light beam of the light-emitting diode is blocked, the corresponding p osensitive resistor senses and produces a change in resistance value. The syst