Guitar Tuner

For our final project in our Electrical Engineering course at Harvey Mudd College, we decided to create a guitar tuner using basic electrical components. See attached write-up for in depth description of project.

Supplies

MCP601 Op-Amp (x2)

TL081 Op-Amp (x1)

Microphone (x1) [site: CMA-4544PF-W Electret Condenser Microphone with MAX4465 Microphone Preamplifier]

Green LED (x2)

1 kOhm Resistor (x5)

100 kOhm Resistor (x2)

6.8 kOhm Resistor (x3)

3.9 kOhm Resistor (x1)

4.7 kOhm Resistor (x1)

3.3 kOhm Resistor (x1)

680 Ohm Resistor (x2)

10 uF Capacitor (x2)

1 uF Capacitor (x1)

0.1 uF Capacitor (x2)

Diode (x2)

Step 1: Microphone Circuit

Build microphone circuit shown above.

Notes:

The positive and negative rails of the op-amp should be powered with 5 volts and negative 5 volts respectively.

The gain resistors are dependent on how loud the guitar is played. Adjust the 3.9kOhm resistor as needed.

Step 2: Tuner Circuit

Build tuner circuit shown above.

Note:

The positive and negative rails of the op-amps should be powered with 5 volts and 0 volts (grounded) respectively.

Step 3: Testing Circuit

Once completed with building the circuit, play "A" string into the microphone and tune the guitar based on the LEDs.

Note: This tuner is intended for 440Hz (A string).