At the beginning of this week, I helped my teammates prepare for the demo. We debugged an issue where the audio file was being saved as a .webm file instead of a .wav file. This opportunity allowed me to read a lot of Django documentation which I’m sure will be helpful when it comes to writing glue code between further parts of the system in the upcoming weeks.
After discussion with the professors during the Wednesday demo and discussions with my teammates afterwards, I began to reconsider the way I was implementing volume in the key pressing. Initially, I had made some assumptions:
1. Since 5N was the minimum force for the sound to be heard, any increment less than 5N would not result in a noticeable difference in sound.
2. Discrete levels of volume were “good enough” for the purposes of our project.
Upon further consideration, I realized that this was unnecessarily limiting the dynamic volume range of our system. Since we are using PWM to control the solenoid force, we can have any force level from 0 to 100% (0 to 25N). Since we need at least 5N to sound a key, this gives us 5 to 25N. I also adjusted the volume level calculations to better reflect the relationship between force and volume. Since the audio processing output gives us amplitude in Pascals (Newton over metres squared) and the distance is a constant, the volume parameter is linear with Newtons. Previously, I mistakenly assumed that the volume was in decibels and had implemented a logarithmic relationship between with two.