THE MOTIVATION

What were the most challenging steps along the way?

The first challenge behind this project was determining where to start. We could have read the signal coming from the guitar using vibration sensors, microphones, or the output from the guitar's built in jack. We knew we wanted a more affordable final product that would also be robust and able to perform in more difficult conditions. For this reason, we felt that microphones may pickup unwanted background noise that would corrupt out results, and that vibration sensors might be too difficult to properly use and survive rough travelling conditions. Our final choice was to go with the output from the guitar jack. While this does limit us to tuning guitars that have an output jack, this tuner is designed for beginners and travelling musicians, most of which will have a guitar with an output jack. 

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The next big challenge was determining what hardware to use as this would also determine our software. We ultimately chose to go with an Arduino UNO, one of if not the most common arduino boards out there, as it has a large amount of online support as well as being relatively inexpensive. Because of our choice of microcontroller, we would need to offset and amplify the signal from the guitar so that it could be read, thus requiring us to design and order a PCB, as a PCB would provide much more robustness than a breadboard at a minimally increased cost. 

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A challenge we were not expecting was the choice of motor. In our research, we found that almost no one had documented what motor they chose to use, instead saying they used whatever motor they could find. In addition, very few sources listed a required amount of torque to turn various guitar pegs. We were very lucky that our TA, Georges, was able to find a motor already in our stock that would work for our guitar we were testing on. We used the Nema 17 stepper motor, which offers very precise turns and enough torque for our needs.

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There were some challenges when it came to designing the 'user experience' portion of this project. First and foremost was getting the box that houses all of the electronics as well as ports to access things such as the motor and 1/4" cable from the guitar. The laser-cutter we planned to use had issues with the focusing lens meaning it could not cut our material, and since we wanted the final housing to be precise, we had to wait until it was fixed. During that time, we decided to use hinges and a magnetic lock to create a lid to allow access to the inside of the tuner should any repairs need to be done. However, we forgot to alter the design of the box to accommodate hinges. Once it came time to cut our housing material and put it all together, extra cuts had to be made in order to fit the hinges and make the tuner accessible from the outside.