Here is a guitar tuner I made with an Arduino Uno and some stuff I had lying around. It works like this:
There are 5 buttons each which will produce a different note in the standard guitar tuning EADGBE. Since I only had 5 buttons, I wrote code so that if you hold down the 'E' button, it will produce a high E, while if you just tap the button it will produce a low E.
When you press the cooresponding button, the letter of the note will appear on the 7 segment display, and the active buzzer will produce the correct pitch. The high E is indicated on the display by 'E.' while the low E is indicated as 'E'.
It doesn't sound so pretty because I used a crappy active buzzer, although it does work. I have tuned my guitar successfully with it multiple times.
Step 1: What You'll Need
For this project I used the following hardware:
74HC595 Shift Register
8x 220 Ohm Resistors
7 Segment Display
5 Mechanical Buttons (Preferably 6)
Step 2: Wiring
Sorry it doesn't look to pretty. This is my first time with the schematic software. I tried to color coordinate so you could follow each signal.
Step 3: Code
The code can be found on github at: https://github.com/Jhertz2/ArudinoGuitarTuner