correct integral mouse code

arduino_demos/integral_mouse.ino

@@ -1,44 +1,111 @@
-// File led_pendulum.ino
-// Makes a Circuit Playground or Circuit Playground Express
-// light up with one of three colors, depending on the acceleration
-// seen on a chosen axis
+// File integral_mouse.ino
+// Makes a Circuit Playground or Circuit Playground Express into
+// an accelerator mouse.
 // (c) 2022 Rich Cameron, for the book Make:Calculus
 // Licensed under a Creative Commons, Attribution,
 // CC-BY 4.0 international license, per
 // https://creativecommons.org/licenses/by/4.0/
 // Attribute to Rich Cameron, at
 // repository github.com/whosawhatsis/Calculus
 
+#ifndef ARDUINO_AVR_CIRCUITPLAY
+  #ifndef ARDUINO_SAMD_CIRCUITPLAYGROUND_EXPRESS
+    #error Please select Circuit Playground/Circuit Playground Express.
+  #endif
+#endif
+
 #include <Adafruit_CircuitPlayground.h>
+#include <Mouse.h>
+#include <Wire.h>
+#include <SPI.h>
+
+#define SPEED .1
+#define SAMPLE 10 //Number of samples in the average
+
+boolean lb = 0;
+boolean rb = 0;
+
+float v[2] = {0, 0};
+float cal[2] = {0, 0};
+
+#define X 0
+#define Y 1
+
+unsigned long t = 0;
 
-#define X //capital X, Y or Z, the direction you will be swinging
-//use Y for Classic, X for Express (with USB pointed up)
-//(see the markings by your board's accelerometer)
-#define THRESHOLD 0.3
+boolean lift() {
+  return !CircuitPlayground.leftButton();
+}
+
+boolean leftmouse() {
+  return CircuitPlayground.rightButton();
+}
+
+boolean rightmouse() {
+  return 0;
+}
 
 void setup() {
   CircuitPlayground.begin();
-  CircuitPlayground.setBrightness(255);
-  CircuitPlayground.clearPixels();
+  Mouse.begin();
+  calibrate();
 }
 
 void loop() {
-  float motion =
-    #if defined(X)
-      CircuitPlayground.motionX();
-    #elif defined(Y)
-      -CircuitPlayground.motionY();
-    #elif defined(Z)
-      CircuitPlayground.motionZ();
-    #else
-      #error No valid axis specified.
-    #endif
-
-  CircuitPlayground.clearPixels();
-  if(motion > THRESHOLD) for(int i = 0; i < 3; i++)
-    CircuitPlayground.setPixelColor(i, 255, 0, 0);
-  else if(motion < -THRESHOLD) for(int i = 7; i < 10; i++)
-    CircuitPlayground.setPixelColor(i, 0, 0, 255);
-  else for(int i = 4; i < 6; i++)
-  CircuitPlayground.setPixelColor(i, 0, 255, 0);
+  t = millis();
+  if(lb != leftmouse()) {
+    lb = !lb;
+    if(lb) Mouse.press(MOUSE_LEFT);
+    else Mouse.release(MOUSE_LEFT);
+  }
+  if(rb != rightmouse()) {
+    rb = !rb;
+    if(rb) Mouse.press(MOUSE_RIGHT);
+    else Mouse.release(MOUSE_RIGHT);
+  }
+  if(lift()) {
+    v[X] = 0;
+    v[Y] = 0;
+    calibrate();
+    return;
+  }
+
+  float dv[2] = {0, 0};
+
+  // Average acceleration for SAMPLE samples. 
+
+  for(int i = 0; i < SAMPLE; ++i) {
+    dv[X] += CircuitPlayground.motionX();
+    dv[Y] += CircuitPlayground.motionY();
+  }
+  dv[X] /= SAMPLE;
+  dv[Y] /= SAMPLE;
+
+  // Now integrate acceleration to get velocity.
+  // Use the average acceleration we just computed. 
+
+  unsigned long dt = millis() - t;
+
+  v[X] += (dv[X] - cal[X]) * dt;
+  v[Y] += (dv[Y] - cal[Y]) * dt;
+
+  // Now export result consistent with screen coordinates
+  // which have origin at top left.
+  // Classic and Express boards have rotated coordinates 
+  // from each other.
+
+  #if defined(ARDUINO_AVR_CIRCUITPLAY)
+    Mouse.move((int)-v[Y] * SPEED, (int)-v[X] * SPEED, 0);
+  #elif defined(ARDUINO_SAMD_CIRCUITPLAYGROUND_EXPRESS)
+    Mouse.move((int)v[X] * SPEED, (int)-v[Y] * SPEED, 0);
+  #endif
+}
+
+void calibrate() {
+  cal[X] = 0;
+  cal[Y] = 0;
+  for(int i = 0; i < SAMPLE; ++i) {
+    cal[X] += CircuitPlayground.motionX() / SAMPLE;
+    cal[Y] += CircuitPlayground.motionY() / SAMPLE;
+  }
 }