Recommendations for Next Time
Although this project was quite complex, time and availabe hardware
placed a limit on the capabilities of the Shredder. There are numerous
possiblities to expand upon it; here is a brief list:
The biggest problem with this system is that we only have 8-bits to
play with. It's difficult to get clarity with only 256 voltage levels.
In fact we even dropped the 8th bit because we required the extra port pin
for the ADC's chip select. For a halfway decent sound, at least 16 bits
resolution should be used. More bits would eliminate some of the buzziness and
Despite the fact that this is a digital effects processor, there is quite a
lot of analog circuitry included. Naturally, when introducing analog components,
we introduce noise. In an attempt to filter out the noise we added capacitors in
various strategic locations to create low pass filters to get rid of the high
frequency noise components. Unfortunately we filtered out some of the high
guitar frequencies as well. More careful calculations in selecting a high pass
filter would help provide even better sound.
If we had more time, we would have included more special effects such as chorus and flange. We would also have liked to allow for multiple effects to be active at one time, but unfortunately that code was too complicted to do in this amount of time.
One piece of advice for anyone attempting a project like this is to order any parts
needed well ahead of time. Having the parts ready to go avoids problems like having the project due on Monday without having the necessary RAM, or other such hypothetical situations.
One last piece piece of advice: try to avoid any contact with demons when
working with microcontrollers - see Results section for more information.
EE 476 - Final Project - Sp '00