The document describes the Gibson Guitar Robot, which automatically tunes guitars using microcontrollers and motors. It analyzes string frequencies using a piezo pickup and C8051F120 microcontroller. Based on the detected frequencies, preset tunings, and temperature, the microcontroller controls Rohm BA6845FS motor drivers to rotate tuning pegs until the strings reach the desired pitch. It allows for automatic and accurate tuning in seconds, solving issues like heat-induced detuning and the inconvenience of manual tuning.

1. Yet another application of microcontrollers…
GIBSON GUITAR ROBOT
Team – Sleeping Mode
Abhishek Anand - BG107Cs003
Abhishek Mishra - BG107CS004
Akash Gupta - BG107CS010
Manish Kumar - BG107CS062
Paramjeet - BG107CS080
Subhash Choudhary - BG107Cs119

2. The Problems of a Guitarist
• Tuning mechanism hasn’t evolved much.
• Each peg is still turned manually to get the right tone.
• Factors like heat change the tone of strings.
• Stretched strings are very tough to keep in tone.
• People rely on software like Guitar Tuner Pro.
• Inconvenience.
• Lot of time gets wasted.

3. The Solution
Gibson Guitar Robot

4. The Solution
Gibson Guitar Robot
• End to manual peg twisting
• Automatic tuning in seconds!
• Accurate results
• Uses Microcontroller and Motors

5. Features
Gibson Guitar Robot
• Dynamic Tuning
• Read and Right
• Speed Dial
• Switch Beats
• 200 tunings between battery
charges

6. The Setup

7. The Setup
MCK – Master Control Knob
• adjusts volume – normal function
• on pull – becomes tuning selector
• LEDs show status of tuning
• shows battery level (1-10)

8. The Setup
Charging System
• 2.4 V NiCd battery pack
• Stepped up to 12V to power other parts (motors etc)
• 90 minutes full charge
•200 tunings per full charge

9. The Setup
Powerhead Locking Tuners
• Rohm's BA6845FS motor drivers
• Rotates to pull strings for tuning
• RPM is reduced by ratio of 500:1
• also works for manual tuning

10. The Setup
Piezo Pickups
• detects frequencies
• feeds signals to Data Transmitting Tailpiece
• the signals are multiplexed into C8051F120 MCU’s
Analog/Digital input

11. The Setup
Data Transmitting Tailpiece
• contains Silicon Labs C8051F120 12-bit MicroController
• uses crystal-derived reference frequency, to decide if string’s
frequency is flat, sharp or on pitch.
• depending on the string’s frequency, controls the motors in
tuners

12. Silicon labs C8051F120 12-bit
• High Speed 8051 uC core
• 100 MIPS Mixed-Signal with 64 I/O Lines
• 5 Timers + 1 Watch Dog Timer
• 128K Byte In-System Programmable FLASH
• 256 Bytes RAM
• 8K Bytes XRAM
• 2 UARTS
• Supply Voltage 2.7V – 3.6V

13. Working
#1 Master Control Knob is pulled up
• this enables the C8051F120 unit
• lets user load a preset

14. Working
#2 Pickup detects frequencies
• converts string vibrations into frequencies
• multiplexes all 6 string frequencies
• feeds them to C8051F120 ‘s input

15. Working
#3 Tailpiece (MCU) analysis
• C8051F120 MCU analyses the signals from pickup
• decides which string to tune
• decides how much to tune on the basis of
• preset loaded
• temperature
• sends signals to Rohm's BA6845FS motor drivers

16. Working
#4 String Tuning
• Rohm's BA6845FS motor driver controls the tiny servo
motors attached to each string
• Each string is rotated unless it reaches desired frequency

17. Precautions
• Make sure no two strings touch each other – might lead to short
circuit
• Make sure MCK is not pulled when while guitar is in storage, this
would drain out the battery completely
• While strings are removed, make sure that Tailpiece (MCU)
doesn’t move, this could damage its connectors
• Don’t turn the pegs manually while MCK is pulled, i.e. Robot is
ON

18. Conclusions
• We saw, how a microcontroller helps in automating difficult
tasks.
• A microcontroller makes redundant tasks easier.
• Gibson Guitar Robot is able to take intelligent decisions by help
of a microcontroller.
• A microcontroller adds more functionalities and values to a
product.

19. Thank You…
For more information -
• http://www.gibson.com/robotguitar/guitar.html
• http://www.eetimes.com/showArticle.jhtml?articleID=207400963
• C8051F120 Datasheet
http://www.datasheetarchive.com/C8051F120-datasheet.html