View source for 220c Spring 2018 ~bjosie


== Phase I - Analog ==

Although I consider myself a guitar pedal enthusiast, I had never explored the creation of an analog pedal myself. I have seen countless product demonstrations, and as my understanding of electronics has expanded over my time at Stanford, I have been wondering how I might gain a greater understanding of the circuitry involved in the sound sculpture in pedals, or at least a greater insight of their design.

After coming across a couple wah pedals in the Max Lab, I made the logical step of tearing them open to inspect the insides.



With one note reading "Scratchy sound when pot is moved," these pedals were in the junk bin for a reason. They were not in superb shape for practical use, but I was lucky they were extremely intact, and I could explore the insides. I found circuit diagrams for a simple wah as well as the specific wah in question and compared the diagram with the actual pedal.

[[File:Users/benjaminjosie/desktop/wah1.gif]]
[[File:Users/benjaminjosie/desktop/crybabyCircuit.png]]

After several trials of removing/swapping resistors, capacitors and potentiometers, I began to realize the circuit was less interesting to me than was the design of the pedal itself. The mechanics of the tilted surface, the rolling pot, and the way the designers filled the housing piqued my interest. This became even more evident when I busted open my Boss SD-1. Boss, a company whose name has become synonymous with indestructible, sure knows how this process works.


Each piece of the pedal is placed extremely intentionally, using rugged materials and leaving nothing to luck. The insides were all screwed into place, and it was rather straightforward to be able to deconstruct. Inside, wires were even zip-tied to be directed into place.

In this exploration, I realized two things: Nine weeks would not provide me with enough time to meaningfully understand the workings of an analog circuit; I am more intrigued by the physical design anyway, which makes me ready to move onto....

== ToeCandy ==

In 250a, I used electronics for the first time to create what I deemed a digital pedalboard called ToeCandy. While the finished design itself is extremely basic and not tremendously practical, the idea of a digital pedalboard has stuck with me, and I have not seen one in the time since I took 250a. 

The idea would be to create a system of FSRs to be able to send MIDI control data to any DAW to use as analog signal to affect any parameter of the user's choosing. In the design I am hoping to create, each pedal would have one FSR/control surface, but the beauty would be it's ability to be multiplexed, with a handful of pedals working together, able to affect a number of parameters at any time. The design would be a small housing, hopefully not much bigger than a standard guitar pedal, so that it can attach to any standard pedalboard.

As the design develops, it wirelessly transmit data to your device, as well as wirelessly connect to other pedals to transmit each pedal's data through one BlueTooth channel.

==Early Sketches==
[[File:proofofconcept.jpeg|400px|A microcontroller with two force sensors, to build the simple circuit]]

The above picture shows a microcontroller with two force sensors, to build the simple circuit as the basis for the pedal. The planned design is to have a tilted platform with to ~squishy~ pads resting atop the force sensors as the primary user interface. The requirements of the circuit are rather small, and moving forward with a first prototype should not be too difficult.

== First Prototype ==


== Physical Model ==

[[File:Firstprototype1.JPG|400px]][[File:Firstprototype2.JPG|400px|right]]

The above images show the first prototype of the pedal. The FSR's sit on the board, wired to the microcontroller, giving analog voltages which the microcontroller computes to output a meaningful MIDI control value. The foam pads help to absorb some of the pressure put by the user's foot control. Without these pads, the FSR's would be much too sensitive to utilize any meaningful control output. The LED strip was put in place to indicate to the user their output without having to monitor their computer at the same time. Adafruit's NeoPixel was used for this function, which can allow the whole strip to be controlled on an LED-by-LED basis, using only one digital out pin on the controller.