Project
| # | Title | Team Members | TA | Documents | Sponsor |
|---|---|---|---|---|---|
| 25 | Auto-Guitar Tuner |
Daniel Cho Ritvik Patnala Timothy Park |
Eric Tang | design_document1.pdf final_paper1.pdf presentation1.pptx proposal1.pdf video |
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| **Handheld Automatic Guitar Tuner** **Team Members:** Timothy Park (twpark2) Daniel Cho (hc55) Ritvik Patnala **Problem:** When playing guitar, being in tune is essential. When strings are not properly tuned to their correct pitches, the notes played can clash with each other causing what listeners perceive as being "off" or "out of tune." Accurately tuning a guitar is a challenge for both beginners and experienced players. Traditional tuners require the musician to manually turn tuning pegs while reading pitch information, which can be inconsistent and time-consuming. An automatic solution that can both detect pitch and physically adjust the tuning peg would reduce errors, speed up tuning, and improve usability in practice and performance settings. **Solution:** We propose a handheld automatic guitar tuner that integrates pitch detection and motorized peg adjustment into one device. The system will capture string vibrations, process them using a microcontroller to identify the current pitch, and automatically rotate the tuning peg with a small motor until the string is in tune. Since the handheld device tunes one string at a time, it can be used on different guitars without needing to worry about different spacing in between pegs and strings. A compact LED screen will display the detected pitch and tuning status, while four buttons (Power, String Select, Mode, Start) provide simple user control. The String Select button allows the user to cycle through the six guitar strings. Each press moves the selection to the next string in order: low E, A, D, G, B, high E, then back to low E again. This circular navigation lets users easily choose which string to tune without confusion or the need for multiple buttons. The Mode button lets users toggle between preset tuning standards (Standard, Drop D, Open G, etc) to accommodate various playing styles and preferences. The design will run on a rechargeable battery, with all subsystems integrated into a custom PCB for portability and reliability. **Solution Components:** Subsystem 1: Audio Sensing and Pitch Detection Purpose: Capture the sound/vibration of the guitar string and convert it to a clean, digitizable signal. Components: A transducer (Piezo or electret mic) is used to convert the string vibration to an electrical signal. If a mic is used, filtering algorithms will be implemented to remove unwanted ambient noise. Low noise op-amp or preamplification can boost the tiny sensor signal to a usable voltage for the ADC. Anti-aliasing filter removes any high frequency noise or harmonics above Nyquist so that the sampled form represents real string motion. This can prevent false pitch estimates. MCU ADC input samples the signal at a steady rate. Clean samples are the raw materials/inputs to the pitch detection algorithm. Subsystem 2: Microcontroller Purpose: Run pitch detection algorithms and control the motor Components: The microcontroller is used for multiple aspects including streaming the audio in via ADC. It is also used to run the pitch detection algorithm and determine the motor speed/direction to achieve the optimal tuning. Apart from this, it also updates the data on the screen and takes in inputs from the buttons. GPIO inputs (buttons) can read the users intent including power, mode and string selection, and start/stop. Debouncing will ensure one clean press. I2C bus for OLED display and fuel gauge: The 2 wire link the MCU uses to communicate with the display to show the note, offset and battery. Subsystem 3: Motor Purpose: Physically adjust the guitar tuning peg to reach the correct pitch. Components: A DC gear motor provides the mechanism to rotate a guitar’s tuning peg. This needs to ensure that we trade speed for torque so that peg can be turned smoothly and precisely to prevent the string from snapping. Removable socket attachment allows the tuner to be attached to different peg shapes. A quick swap lets you tune various guitars without redesigning the whole tool. Subsystem 4: Power Unit Purpose: Provide stable power to both logic and motor subsystems Components: A Li-ion battery will be the primary power source, due to the energy density and rechargeability. Typically specs at 3.7 volts with potential to allow for multiple hours of operations. Charger IC with USB-C input can be utilized to allow safe and reliable charging of the Li-ion battery. The Buck regulator will be used to cut voltage levels required by different components (usually 3.3V or 5V). Fuel gauge Subsystem 5: User Interface Purpose: Provide real-time pitch feedback and allow user input Components: An OLED display is used to showcase the note/string you want to tune, a cents bar/needle so the user can see whether the string needs to be tightened or loosened. It also shows the battery and the chosen mode. Four push buttons (Power, Mode, String Select, Start) Piezo Buzzer to generate beep sounds to signal successful tuning. This would be driven by the microcontroller’s GPIO for tone generation. **Criterion for Success:** The device tunes all six guitar strings to within ±12 cents of the target pitch, which is the threshold where most people can perceive a note as out-of-tune. Possibly ±5 cents for further accuracy. Visual indication (such as an LED) signals when each string reaches its correct pitch. The tuner should function reliably on both acoustic and electric guitars without causing any damage to the instrument or strings. Each string should be tuned within a reasonable time frame (under 20 seconds per string). OLED display refreshes pitch feedback at least 5 times per second |
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