Hi everyone, today I will guide you how to make a powerful piano keyboard with LM555 IC. OK let's go! Piano keyboard description Here we will show how to build a piano keyboard which generate simple electronic keyboard musical notes DO, RE, MI, FA, SOL, LA, SI, DO1 and RE1, as shown in the following diagram (keyboard piano). Piano Keyboard with IC LM555 Piano keyboard operation circuit This circuit has a piano keyboard wave generator essentially comprises a 555 which operates as an astable multivibrator circuit. This type of operation is characterized by an output square wave of width defined by the designer. The outgoing wave frequency can be controlled by the resistor is connected between pins 7-8 and 2-7 in addition to the capacitor connected to pin 2 grounded. The resulting frequency can be calculated under the following equation. Where R eq is the result according to the push button is pressed on the keyboard piano. Therefore we can in our piano keyboard similar sound of an...