From 777f32b3af9bff8ace6eadf0b895b5f5ee886e93 Mon Sep 17 00:00:00 2001
From: Sophie Schiller <sophie.schiller01@gmail.com>
Date: Tue, 16 Feb 2021 14:41:12 +0100
Subject: [PATCH] add jumping balls

---
 src/main.ino | 98 ++++++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 95 insertions(+), 3 deletions(-)

diff --git a/src/main.ino b/src/main.ino
index 7023734..c7216a0 100644
--- a/src/main.ino
+++ b/src/main.ino
@@ -9,12 +9,12 @@
 
 #define LED_PIN     7
 
-byte mode = 2; // 0 for acceleration, 1 for fire, 2 for waterfall, 3 pride, 4 glitter, 5 off
-const byte NUM_MODES = 6;
+byte mode = 5; // 0 for acceleration, 1 for fire, 2 for waterfall, 3 pride, 4 glitter, 5 pulse, 6 off
+const byte NUM_MODES = 8;
 const byte debug = 3;
 const byte STRIPS = 6;
 const byte NUM_LEDS = 10;
-const byte FRAMES_PER_SECOND = 30;
+const byte FRAMES_PER_SECOND = 60;
 const float range = 0.5; //accelleration range in g
 
 const byte BRIGHTNESS = 50;
@@ -23,6 +23,18 @@ const byte SPARKING = 50;
 uint8_t gHue = 0;
 
 
+const float GRAVITY = -9.81;              // Downward (negative) acceleration of gravity in m/s^2
+const float h0 = 1;                  // Starting height, in meters, of the ball (strip length)
+const byte NUM_BALLS = STRIPS;                 // Number of bouncing balls you want (recommend < 7, but 20 is fun in its own way)
+
+float h[NUM_BALLS] ;                         // An array of heights
+float vImpact0 = sqrt( -2 * GRAVITY * h0 );  // Impact velocity of the ball when it hits the ground if "dropped" from the top of the strip
+float vImpact[NUM_BALLS] ;                   // As time goes on the impact velocity will change, so make an array to store those values
+float tCycle[NUM_BALLS] ;                    // The time since the last time the ball struck the ground
+int   pos[NUM_BALLS] ;                       // The integer position of the dot on the strip (LED index)
+long  tLast[NUM_BALLS] ;                     // The clock time of the last ground strike
+float COR[NUM_BALLS] ;                       // Coefficient of Restitution (bounce damping)
+
 float accelerationHistory [STRIPS];
 
 MPU6050 mpu(Wire);
@@ -56,7 +68,18 @@ void setup() {
 	Serial.println(F("Calculating offsets, do not move MPU6050"));
 	delay(1000);
 	mpu.calcOffsets(true,true); // gyro and accelero
+
+	for (int i = 0 ; i < NUM_BALLS ; i++) {    // Initialize variables
+		tLast[i] = millis();
+		h[i] = h0;
+		pos[i] = 0;                              // Balls start on the ground
+		vImpact[i] = vImpact0;                   // And "pop" up at vImpact0
+		tCycle[i] = 0;
+		COR[i] = 0.90 - float(i)/pow(NUM_BALLS,2); 
+	}
+
 	Serial.println("Done!\n");
+
 }
 
 float calculateOrientationData() {
@@ -201,6 +224,66 @@ void drawGlitter(){
 	leds[pos] += CHSV( gHue + random8(64), 200, 255);
 }
 
+void drawPulse(){
+	static int current_step;
+	float steps = 2000;
+	CRGB color;
+	for (int strip = 0; strip < STRIPS; strip++){
+		//float f = 0.5-0.5*cos(360/steps*float(current_step) + 360/steps*360/float(STRIPS)*float(strip));
+		float f = cos(360/steps*float(current_step) + 360/steps*360/float(2*STRIPS)*float(strip));
+		if (f < 0) f = 0;
+		color = CHSV(gHue , 255, int(255*f));
+		for( int j = 0; j < NUM_LEDS; j++) {
+			int pixelnumber =  (strip * NUM_LEDS) + j;
+			leds[pixelnumber] = color;
+		}
+	}
+	current_step++;
+}
+
+void drawKunsisLila(){
+	static int current_step;
+	float steps = 2000;
+	CRGB color;
+	for (int strip = 0; strip < STRIPS; strip++){
+		float f = cos(360/steps*float(current_step) + 360/steps*360/float(2*STRIPS)*float(strip));
+		if (f < 0) f = 0;
+		color = CHSV(224 , 255, int(255*f));
+		for( int j = 0; j < NUM_LEDS; j++) {
+			int pixelnumber =  (strip * NUM_LEDS) + j;
+			leds[pixelnumber] = color;
+		}
+	}
+	current_step++;
+}
+
+void bounceBalls(){
+	for (int i = 0 ; i < NUM_BALLS ; i++) {
+		tCycle[i] =  millis() - tLast[i] ;     // Calculate the time since the last time the ball was on the ground
+
+		// A little kinematics equation calculates positon as a function of time, acceleration (gravity) and intial velocity
+		h[i] = 0.5 * GRAVITY * pow( tCycle[i]/1000 , 2.0 ) + vImpact[i] * tCycle[i]/1000;
+
+		if ( h[i] < 0 ) {                      
+			h[i] = 0;                            // If the ball crossed the threshold of the "ground," put it back on the ground
+			vImpact[i] = COR[i] * vImpact[i] ;   // and recalculate its new upward velocity as it's old velocity * COR
+			tLast[i] = millis();
+
+			if ((vImpact[i] < 0.01 ) && (calculateOrientationData()>1.5)) {
+				vImpact[i] = vImpact0;  // If the ball is barely moving, "pop" it back up at vImpact0
+			}
+		}
+		pos[i] = round( h[i] * (NUM_LEDS - 1) / h0);       // Map "h" to a "pos" integer index position on the LED strip
+	}
+
+	for (int i = 0 ; i < STRIPS*NUM_LEDS ; i++) {
+		leds[i] = CRGB::Black;
+	}	
+	//Choose color of LEDs, then the "pos" LED on
+	for (int i = 0 ; i < NUM_BALLS ; i++) leds[(i * NUM_LEDS)+pos[i]] = CHSV( uint8_t (i * 40) , 255, 255);
+	//Then off for the next loop around
+}
+
 void drawOff(){
 	fadeToBlackBy( leds, STRIPS*NUM_LEDS, 10);
 }
@@ -234,6 +317,15 @@ void loop() {
 		drawGlitter();
 	}
 	else if (mode == 5) {
+		drawPulse();
+	}
+	else if (mode == 6) {
+		drawKunsisLila();
+	}
+	else if (mode == 7) {
+		bounceBalls();
+	}
+	else if (mode == 8) {
 		drawOff();
 	}
 	FastLED.show();