141 lines
3.6 KiB
C++
141 lines
3.6 KiB
C++
/****************************************************
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* Arduino Sketch: Shape-Based Chord Detection + RC Filter
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* - Reads 3 SoftPot sensors on A0, A1, A2 (with resistor+cap)
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* - Sorts them in descending order to detect chord shape (A, D, E)
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* - Outputs "ChordName|val1,val2,val3" over Serial at 9600 baud
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*
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* 2025-03-xx
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****************************************************/
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#define S1_PIN A0
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#define S2_PIN A1
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#define S3_PIN A2
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// Toggle this to test shape detection without real sensors
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#define SIMULATION_MODE true
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#define CYCLE_INTERVAL 3000 // ms to switch chord in simulation
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// Threshold for ignoring no-touch floating (~500)
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#define NO_TOUCH_MIN 400
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#define NO_TOUCH_MAX 600
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// Minimal difference between High and Low for shape detection
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#define MIN_DIFF 10
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// For simulation
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unsigned long lastSwitchTime = 0;
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int currentFakeChord = 0; // cycles 0=A, 1=D, 2=E
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void setup() {
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Serial.begin(9600);
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}
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void loop() {
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int s1, s2, s3;
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if (SIMULATION_MODE) {
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// Switch chord every 3 seconds
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if (millis() - lastSwitchTime > CYCLE_INTERVAL) {
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lastSwitchTime = millis();
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currentFakeChord = (currentFakeChord + 1) % 3;
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}
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// Fake sensor values for chord shapes:
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switch (currentFakeChord) {
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case 0: s1 = 800; s2 = 600; s3 = 400; break; // A
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case 1: s1 = 700; s2 = 200; s3 = 600; break; // D
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case 2: s1 = 200; s2 = 300; s3 = 800; break; // E
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}
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} else {
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// Real sensor reading:
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s1 = analogRead(S1_PIN);
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delay(5); // let RC settle
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s2 = analogRead(S2_PIN);
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delay(5);
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s3 = analogRead(S3_PIN);
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delay(5);
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}
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// Convert raw readings into a chord name
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String chordName = detectChordShape(s1, s2, s3);
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// Output e.g. "A|60,50,55"
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Serial.print(chordName);
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Serial.print("|");
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Serial.print(s1); Serial.print(",");
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Serial.print(s2); Serial.print(",");
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Serial.println(s3);
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delay(200);
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}
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/*****************************************************
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* detectChordShape():
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* - Filters out 'no-touch' readings
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* - Sorts in descending order
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* - Matches pattern for A, D, E
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*****************************************************/
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String detectChordShape(int raw1, int raw2, int raw3) {
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int s1 = filterNoTouch(raw1);
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int s2 = filterNoTouch(raw2);
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int s3 = filterNoTouch(raw3);
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// If all -1 => no real touches
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if (s1 == -1 && s2 == -1 && s3 == -1) {
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return "None";
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}
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// Sort them descending
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int arr[3] = {s1, s2, s3};
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int idx[3] = {1, 2, 3};
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for(int i=0; i<2; i++) {
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for(int j=0; j<2-i; j++){
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if (arr[j] < arr[j+1]) {
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int tempVal = arr[j];
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arr[j] = arr[j+1];
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arr[j+1] = tempVal;
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int tempIdx = idx[j];
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idx[j] = idx[j+1];
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idx[j+1] = tempIdx;
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}
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}
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}
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// Check difference high-low
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int diffHL = arr[0] - arr[2];
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if (diffHL < MIN_DIFF) {
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return "None";
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}
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// Pattern matching
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// Example A shape => (S1=High, S2=Mid, S3=Low) => index[0]==1, index[1]==2, index[2]==3
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if (idx[0] == 1 && idx[1] == 2 && idx[2] == 3) {
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return "A";
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}
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// D shape => (S1=High, S3=Mid, S2=Low) => index[0]==1, index[1]==3, index[2]==2
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if (idx[0] == 1 && idx[1] == 3 && idx[2] == 2) {
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return "D";
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}
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// E shape => (S3=High, S2=Mid, S1=Low) => index[0]==3, index[1]==2, index[2]==1
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if (idx[0] == 3 && idx[1] == 2 && idx[2] == 1) {
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return "E";
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}
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return "None";
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}
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/*****************************************************
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* filterNoTouch():
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* Returns -1 if sensor is around 500 => no press
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* Otherwise returns rawVal
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*****************************************************/
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int filterNoTouch(int val) {
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if (val >= NO_TOUCH_MIN && val <= NO_TOUCH_MAX) {
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return -1; // no-touch
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}
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return val;
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}
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