The frequency of each note depends on R2, which must be replaced by a keyboard. The circuit is from Radio Electronics from April 1980. The power supply is 9 V for the amplifier used.
The configuration presented below was obtained in the Linear Application Handbook of the National...
August 2016 - It can be found at Mouser Electronics the new sensors light to digital OPT3002 from...
The figure shows how to divide the frequency of a signal by 17 using the 4017. Additional CMOS...