Guitar Chromatic Tuner
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this tuner is tested on bass guitar. it's not perfect but works for me.
Supplies
2 Resistor
1 Capacitor
1 Operational amplifier
1 Arduino
1 LCD Display
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simple non-inverting operational amplifier. powered by 5 volt from Arduino.
opamp output to 7 pin
code for arduino
Downloads
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you can add switch for bypass