Check the listing for details. 51 Microcontroller Stringless Optoelectronic Piano DIY Keyless Qin Welding Kits. Condition: New. Listed at 11.99 USD. Visit storeItems for saleAbout usProduct DetailsFeatures1.This photoelectric piano has a total of 7 strings, the buzzer emits the corresponding tone level when cutting the strings.2. With LED lights, when cutting the strings, the LED corresponding to the string lights up, a total of 7 LEDs.3. There are no strings, instead of bright beams of light, the user only needs to pluck the beams of light as if plucking the strings, and can still play a melody.4. This production consists of two parts: photosensitive circuit and microcontroller.5. It can stimulate the interest in music and technology, and it is a good creative small production for friends who like DIY. SpecificationSupply voltage: DC4.5V-5.5VLED lights: 8Power socket: DC-005 socketPower cord: USB to DC-005 cableMain board circuit board size: 8.9cm * 6.0cm Stringless piano (photophone) principle:The photoelectric piano is without strings, instead of a bright beam of light, the user only needs to pluck the beam, it is like plucking the strings, and still can play a melody. This production consists of two parts parts, the photosensitive circuit and the microcontroller. When the light-emitting diode beam is blocked, the corresponding photosensitive resistor senses and produces a resistance change, the system consisting of seven photosensitive resistors produces high and low potential changes, and the microcontroller reads the photosensitive resistor high and low potential changes, complete the input of the operating instructions, the microcontroller according to the instruction information to control the data through the serial port to transmit the data, both to the control port of the loudspeaker and to the control port of the running light to be assigned to the value of the corresponding response. The microcontroller assigns values to both the control port for the speaker and the control port for the running light to make them react accordingly. When there is light irradiation, the microcontroller reads the voltage of the photoresistor, which is low at this time. When there is no light irradiation, the microcontroller reads the voltage of the photoresistor, then it is a high level. In this way, when blocking the light of the laser, it can produce the effect of switching in the circuit. The human ear can hear sound frequencies from 20Hz to 20kHz, and harp note frequencies should be in this range. Only, different notes have their own fixed frequencies. The 16-bit timer that comes with the microcontroller can generate the above audio. For example, the harp's standard note la is 440Hz, and its half-cycle is calculated to be 1136 μs. Thus, as long as the pin level is jumped during the half-cycle, a square wave of 440Hz can be generated. Then through the electro-acoustic converter (horn), the standard tone la can be generated, and other notes are also generated in this way. List1 x Electroacoustic kit (soldered not soldered optional)1 x Case1 x Power Cable Payment MethodShipping PolicyFeedbackPayment Method Payment must be received in 5 business days of auction closing. Please leave note for your special request (e.g. Colors or Size) when you pay the order. Any special request cannot be accepted after 24 hours of payment, because most of orders will be processed instantly and same day dispatched. Shipping Policy 1. We only ship to the confirmed address provided by eBay. please make sure your ebay address is 100% matches the address you would like us to ship to. If not, please let us know before we sent you the package, or we will not be responsible for any loss. hope you could understand. 2. Orders will be processed instantly and dispatched within 1-3 business days except hoilday, so we do NOT accept any email/message note after you place orders. 3. All package need to wait 30 days,Please take care it.Less than 30 days,we can't take a refund.Feedback We maintain high standards of excellence and strive for 100% customer satisfaction! Feedback is very important to us. We request that you keep in touch with us immediately BEFORE you give us neutral or negative feedback, so that we can satisfactorily address your concerns.On Jul 11, 2024 at 19:27:40 PDT, seller added the following information: