Click on the links below to hear the results:
The results of our project were very satisfying. I even dare to say that we impressed ourselves and some around us.
Our device was very interactive and responsive to our commands. The LCD and the choice of multiple effects, which were great results of us giving up on the 8515 and the long echo, allowed us to make a user-friendly and fun system. The machine's reactions to us switching between effects were very quick and steady, especially between the different speeds of the same effect (when changing from effect to effect sometimes the noise in between can be annoying).
As far as accuracy goes, it was very hard to get a real idea of what our signal was doing since the guitar signal changes so much over time. Because of this we always used a sine wave to verify that our effects were working properly, which always gave us surprisingly accurate results for the analog processing of the signal (the hardware part of the process). On the other hand, for effects such as reverb and echo, it was almost impossible to rely on theory, since when we add many unpredictable signals together (past signals), the magnitude of the result as well is unpredictable and can cause overflow for the MCU, which comes out as noise. The solution to this problem was mostly trial and error with the code to get the best sound we could.
Our design, I believe, is very safe, since we are using only a +-5V supply with simple devices (+-5V is under our devices' maximum capacity). This means that our circuit should never blow up or over heat after being used for long periods of time. Also, our signal is always going through short and stable protected wires. On the other hand, since we didn't have time to make a suitable box in which to bound our circuit, outside effects such as radiation and transmission of RF signals could if big enough affect our circuit's safety.
The only thing we would have liked to have been safe from is signals in the lab due to either light or other projects. We attribute most of the noise in our signal (since the noise from the MCU was very low although notable) to have come from these elements, since in different days we got different noise levels.
Above all, we consider our design to be very user-friendly and entertaining, despite the undesired noise. The LCD and the use of only two buttons made it easy to go through our machine. If we had been able to make it portable, we would have definitely used it at home and shared it (shown it off) until it stopped working.