Over the past week, I finalized the basic sequencing algorithm and and pitch selection through the Arduino.
Let’s start with the easy one first. Pitch selection, since we only have a small number of keys in use, is just pushing a signal to an Arduino’s digital out pin. However, in the case where we have a far greater number of keys (i.e. future extensions of the project), we would just need to implement a simple switch matrix, allowing us to select from 90 keys with just 9 pins. Pictured below is a basic schematic from the above link:
Tempo is measured in beats per minute, so it’s fairly easy to translate this into a time value for quarter notes and other subdivisions. At 60bpm, you have one quarter note per second (in 4/4 time), at 120bpm, it’s one quarter note every half second, and so on and so forth. For a quick explanation, you can just convert beats per minute to beats per second by dividing by 60, then just flip the expression to find seconds per beat. If you want 16th notes, divide the expression by 4. Dotted expressions are slightly more but still manageable, as they add one half the value of the note, but following dots add half the value of the added value. A single dotted half note adds a quarter note, double dotted adds an eighth note onto that, and a triple dotted note adds another 16th note onto that. Rests are easy to sequence as well, since it’s just a time period of playing nothing (sending no signal). I will need to be slightly careful about rounding errors, but none have popped up so far, so I’m leaving that on the back burner as I work on more pertinent issues. There isn’t much to show here, especially since this was just console output that was similar to one of my teammate’s, but the hope is that next week there will be a very interesting video to post!
The Bayesian Updating algorithm is also being written, but it’s for our secondary mode, so its priority is somewhat lower compared to other tasks. However, some data structures have been set up and testing it should go quickly once it’s finished.
As of now, I’m currently on track and am considering accelerating my schedule with spring break approaching.