Most of the mechanical device is replaced by electronics circuit due to its portability, low cost, stable performance etc.  Here is a simple project “Portable Electronics Organ”  from single chip IC555  in order to replace the mechanical one. The circuit produces simple tones when the keys are pressed. 

Circuit Description

The entire circuit of “Portable Electronics Organ” is build around Timer IC NE555 which is used in oscillator mode. The output is given to loudspeaker LS₁ through DC blocking capacitor C1 from pin 2 (tone generator output). Resistor R₂  through R₆ and capacitors C2 determines the working frequency of the circuit. By selecting switch various tones can be generated. The preset VR1 is tuned to different notes and correct pitch by aural means, where reference notes is provides by pitch pipes or a tuned music instrument.

PART LIST