Description:
Oyun and I decided to create a musical instrument using force sensitive resistors (FSR) that reminded us of drumpads. There are 3 resistors in total, and each represents a different octave. Moreover, if you touch multiple at the same time you again get different octaves. There are different combinations you can try, totaling to 7 altogether. These FSR are used as digital inputs in this case, but we have a potentiometer that moves you along the scale within each octave. By turning the potentiometer, you get the full range of an octave, and by touching the FSR, you get different octaves. We also use an LCD screen to visually represent what you’re playing. Each octave has its own symbol/emoji on the screen and depending on the note you’re playing, the emoji slides across the screen. The higher the note, the farther across the screen it slides.
Video Demonstration:
Image of circuit:
Difficulties:
At first, we wanted to use the FSR as analog inputs and attempted many ideas of using it, but ended up on this method of using them as digital inputs because we liked that you can make different combinations. The FSR reminded us of drumpads, which is why we chose them. We also tried soldering the FSR to wires to make them easier to connect to the breadboard, but that ended up taking way too long, so we just stuck them directly to the breadboard.
We ended up using many wires and at some point, our breadboard became a bit overcrowded, and there was one time when we didn’t realize that one of the resistors was connected to 5V instead of GND.
To detect whether or not someone touched the FSR at first, we checked whether or not the reading was above 0, but realized quickly that even without touching the FSR, it was rarely ever 0. It teetered on values just above 0, so we instead used a threshold of 100.
Another huge problem we encountered in one of our past ideas was using multiple speakers at the same time. We were going to have each FSR correspond to their own speaker, but found out that the tone function doesn’t allow for multiple outputs.
Code Snippets:
Printing the custom emojis:
// make some custom characters:
byte Heart[8] = {
0b00000,
0b01010,
0b11111,
0b11111,
0b01110,
0b00100,
0b00000,
0b00000
};
// LCD screen
if (lastPotInd != potInd) {
lcd.clear();
}
lcd.setCursor(potInd, 0);
lcd.write(byte(melodyInd));
2D array of notes:
int melody[7][12] = {
{NOTE_C1, NOTE_CS1, NOTE_D1, NOTE_DS1, NOTE_E1, NOTE_F1, NOTE_FS1, NOTE_G1, NOTE_GS1, NOTE_A1, NOTE_AS1, NOTE_B1},
{NOTE_C2, NOTE_CS2, NOTE_D2, NOTE_DS2, NOTE_E2, NOTE_F2, NOTE_FS2, NOTE_G2, NOTE_GS2, NOTE_A2, NOTE_AS2, NOTE_B2},
{NOTE_C3, NOTE_CS3, NOTE_D3, NOTE_DS3, NOTE_E3, NOTE_F3, NOTE_FS3, NOTE_G3, NOTE_GS3, NOTE_A3, NOTE_AS3, NOTE_B3},
{NOTE_C4, NOTE_CS4, NOTE_D4, NOTE_DS4, NOTE_E4, NOTE_F4, NOTE_FS4, NOTE_G4, NOTE_GS4, NOTE_A4, NOTE_AS4, NOTE_B4},
{NOTE_C5, NOTE_CS5, NOTE_D5, NOTE_DS5, NOTE_E5, NOTE_F5, NOTE_FS5, NOTE_G5, NOTE_GS5, NOTE_A5, NOTE_AS5, NOTE_B5},
{NOTE_C6, NOTE_CS6, NOTE_D6, NOTE_DS6, NOTE_E6, NOTE_F6, NOTE_FS6, NOTE_G6, NOTE_GS6, NOTE_A6, NOTE_AS6, NOTE_B6},
{NOTE_C7, NOTE_CS7, NOTE_D7, NOTE_DS7, NOTE_E7, NOTE_F7, NOTE_FS7, NOTE_G7, NOTE_GS7, NOTE_A7, NOTE_AS7, NOTE_B7}
};
Mapping potentiometer value to an array index:
potInd = map(potReading, 0, 1000, 0, 12);
Logic for changing the octaves using FSR combos and selecting correct array index:
// all 3
if (fsrReading1 > 100 && fsrReading2 > 100 && fsrReading3 > 100) {
melodyInd = 5;
}
Future Improvements:
Next time, we want to find a way to make the FSR lie flat on a surface so touching them feels more intuitive and more like a drumpad. We can also try controlling different factors about the sounds like the volume. We can also make the note progressions more predictable so that users can go through different notes more easily and play an actual song.