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add new trackball handler

Daniel Zanco 1 jaar geleden
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d4613afad7
1 gewijzigde bestanden met toevoegingen van 198 en 107 verwijderingen
  1. 198 107
      Code/devterm_keyboard/trackball.ino

+ 198 - 107
Code/devterm_keyboard/trackball.ino

@@ -1,5 +1,5 @@
 /*
- * clockworkpi devterm trackball 
+ * ClockworkPi DevTerm Trackball
  */
 #include "keys_io_map.h"
 
@@ -9,122 +9,213 @@
 
 #include <USBComposite.h>
 
-
 #include "trackball.h"
-
-#include "ratemeter.h"
-#include "glider.h"
 #include "math.h"
 
-
- 
-enum Axis: uint8_t {
-  AXIS_X,
-  AXIS_Y,
-  AXIS_NUM,
+// Choose the type of filter (add a `_` to the #define you're not using):
+// - FIR uses more memory and takes longer to run, but you can tweak the FILTER_SIZE
+// - IIR is faster (has less coefficients), but the coefficients are pre-calculated (via scipy)
+#define _USE_FIR
+#define USE_IIR
+
+// Enable debug messages via serial
+#define _DEBUG_TRACKBALL
+
+// Source: https://github.com/dangpzanco/dsp
+#include <dsp_filters.h>
+
+// Simple trackball pin direction counter
+enum TrackballPin : uint8_t
+{
+    PIN_LEFT,
+    PIN_RIGHT,
+    PIN_UP,
+    PIN_DOWN,
+    PIN_NUM,
 };
-static TrackballMode lastMode;
-static int8_t distances[AXIS_NUM];
-static RateMeter rateMeter[AXIS_NUM];
-static Glider glider[AXIS_NUM];
-
-static const int8_t WHEEL_DENOM = 2;
-static int8_t wheelBuffer;
-
-static float rateToVelocityCurve(float input) {
-  //return std::pow(std::abs(input) / 50, 1.4);
-  return std::abs(input) / 30;
-}
-
-template<Axis AXIS, int8_t Direction >
-static void interrupt( ) {
-  distances[AXIS] += Direction;
-  rateMeter[AXIS].onInterrupt();
-  glider[AXIS].setDirection(Direction);
-
-  const auto rx = rateMeter[AXIS_X].rate();
-  const auto ry = rateMeter[AXIS_Y].rate();
-
-  const auto rate = std::sqrt(rx * rx + ry * ry);
-  const auto ratio = rateToVelocityCurve(rate) / rate;
-
-  const auto vx = rx * ratio;
-  const auto vy = ry * ratio;
-
-  if (AXIS == AXIS_X) {
-    glider[AXIS_X].update(vx, std::sqrt(rateMeter[AXIS_X].delta()));
-    glider[AXIS_Y].updateSpeed(vy);
-    
-  } else {
-    glider[AXIS_X].updateSpeed(vx);
-    glider[AXIS_Y].update(vy, std::sqrt(rateMeter[AXIS_Y].delta()));
-
-  }
-
- 
+static uint8_t direction_counter[PIN_NUM] = {0};
+
+// Mouse and Wheel sensitivity values
+static const float MOUSE_SENSITIVITY = 10.0f;
+static const float WHEEL_SENSITIVITY = 0.25f;
+
+#ifdef USE_IIR
+// Infinite Impulse Response (IIR) Filter
+// Filter design (https://docs.scipy.org/doc/scipy/reference/signal.html):
+// Low-pass Butterworth filter [b, a = scipy.signal.butter(N=2, Wn=0.1)]
+static const int8_t IIR_SIZE = 3;
+static float iir_coeffs_b[IIR_SIZE] = {0.020083365564211232, 0.040166731128422464, 0.020083365564211232};
+static float iir_coeffs_a[IIR_SIZE] = {1.0, -1.5610180758007182, 0.6413515380575631};
+IIR iir_x, iir_y;
+#endif
+
+#ifdef USE_FIR
+// FIR Filter
+static const int8_t FILTER_SIZE = 10;
+static float fir_coeffs[FILTER_SIZE];
+FIR fir_x, fir_y;
+
+static void init_fir()
+{
+    // Moving Average Finite Impulse Response (FIR) Filter:
+    // - Smooths out corners (the trackball normally only moves in 90 degree angles)
+    // - Filters out noisy data (avoids glitchy movements)
+    // - Adds delay to the movement. To tweak this:
+    //    1. Change the FILTER_SIZE (delay is proportional to the size, use millis() to measure time)
+    //    2. Redesign the filter with the desired delay
+    for (int8_t i = 0; i < FILTER_SIZE; i++)
+        fir_coeffs[i] = 1.0f / FILTER_SIZE;
 }
- 
-void trackball_task(DEVTERM*dv) {
-  int8_t x = 0, y = 0, w = 0;
-  noInterrupts();
-  const auto mode = dv->state->moveTrackball();
-  if (lastMode != mode) {
-    rateMeter[AXIS_X].expire();
-    rateMeter[AXIS_Y].expire();
-    wheelBuffer = 0;
-  }
-  else {
-    rateMeter[AXIS_X].tick(dv->delta);
-    rateMeter[AXIS_Y].tick(dv->delta);
-  }
-  lastMode = mode; 
-  
-  switch(mode){
-    case TrackballMode::Mouse: {
-      const auto rX = glider[AXIS_X].glide(dv->delta);
-      const auto rY = glider[AXIS_Y].glide(dv->delta);
-      x = rX.value;
-      y = rY.value;
-      if (rX.stopped) {
-        glider[AXIS_Y].stop();
-      }
-      if (rY.stopped) {
-        glider[AXIS_Y].stop();
-      }
-
-      break;
+#endif
+
+#ifdef DEBUG_TRACKBALL
+static uint32_t time = millis();
+
+// Useful debug function
+template <typename T>
+void print_vec(DEVTERM *dv, T *vec, uint32_t size, bool newline = true)
+{
+    for (int8_t i = 0; i < size - 1; i++)
+    {
+        dv->_Serial->print(vec[i]);
+        dv->_Serial->print(",");
     }
-    case TrackballMode::Wheel: {
-      wheelBuffer += distances[AXIS_Y];
-      w = wheelBuffer / WHEEL_DENOM;
-      wheelBuffer -= w * WHEEL_DENOM;
-      if(w != 0){
-        dv->state->setScrolled();
-      }
-      break;
+    if (newline)
+    {
+        dv->_Serial->println(vec[size - 1]);
     }
-  }
-  distances[AXIS_X] = 0;
-  distances[AXIS_Y] = 0;
-  interrupts();
-
-  if(x !=0 || y != 0 || -w!=0) {
-    dv->Mouse->move(x, y, -w);
-  }
- 
+    else
+    {
+        dv->_Serial->print(vec[size - 1]);
+        dv->_Serial->print(",");
+    }
+}
+#endif
+
+template <TrackballPin PIN>
+static void interrupt()
+{
+    // Count the number of times the trackball rolls towards a certain direction
+    // (when the corresponding PIN changes its value). This part of the code should be minimal,
+    // so that the next interrupts are not blocked from happening.
+    direction_counter[PIN] += 1;
 }
 
+static float position_scale(float x)
+{
+    // Exponential scaling of the mouse movement:
+    // - Small values remain small (precise movement)
+    // - Slightly larger values get much larger (fast movement)
+    // This function may be tweaked further, but it's good enough for now.
+    return MOUSE_SENSITIVITY * sign(x) * std::exp(std::abs(x) / std::sqrt(MOUSE_SENSITIVITY));
+}
 
-void trackball_init(DEVTERM*dv){
+void trackball_task(DEVTERM *dv)
+{
+
+#ifdef DEBUG_TRACKBALL
+    // Measure elapsed time
+    uint32_t elapsed = millis() - time;
+    time += elapsed;
+
+    // Send raw data via serial (CSV format)
+    dv->_Serial->print(elapsed);
+    dv->_Serial->print(",");
+    print_vec(dv, direction_counter, PIN_NUM);
+#endif
+
+
+    // Stop interrupts from happening. Don't forget to re-enable them!
+    noInterrupts();
+
+    // Calculate x and y positions
+    float x = direction_counter[PIN_RIGHT] - direction_counter[PIN_LEFT];
+    float y = direction_counter[PIN_DOWN] - direction_counter[PIN_UP];
+
+    // Clear counters
+    // memset(direction_counter, 0, sizeof(direction_counter));
+    std::fill(std::begin(direction_counter), std::end(direction_counter), 0);
+
+    // Re-enable interrupts (Mouse.move needs interrupts)
+    interrupts();
+
+    // Non-linear scaling
+    x = position_scale(x);
+    y = position_scale(y);
+
+    // Wheel rolls with the (reverse) vertical axis (no filter needed)
+    int8_t w = clamp<int8_t>(-y * WHEEL_SENSITIVITY);
+
+    // Filter x and y
+#ifdef USE_FIR
+    x = fir_filt(&fir_x, x);
+    y = fir_filt(&fir_y, y);
+#endif
+#ifdef USE_IIR
+    x = iir_filt(&iir_x, x);
+    y = iir_filt(&iir_y, y);
+#endif
+
+    // Move Trackball (either Mouse or Wheel)
+    switch (dv->state->moveTrackball())
+    {
+    case TrackballMode::Mouse:
+    {
+        // Move mouse
+        while ((int)x != 0 || (int)y != 0)
+        {
+            // Only 8bit values are allowed,
+            // so clamp and execute move() multiple times
+            int8_t x_byte = clamp<int8_t>(x);
+            int8_t y_byte = clamp<int8_t>(y);
+
+            // Move mouse with values in the range [-128, 127]
+            dv->Mouse->move(x_byte, y_byte, 0);
+
+            // Decrement the original value, stop if done
+            x -= x_byte;
+            y -= y_byte;
+        }
+
+        break;
+    }
+    case TrackballMode::Wheel:
+    {
+        if (w != 0)
+        {
+            // Only scroll the wheel [move cursor by (0,0)]
+            dv->Mouse->move(0, 0, w);
+            dv->state->setScrolled();
+        }
+
+        break;
+    }
+    }
+}
 
-  pinMode(LEFT_PIN, INPUT);
-  pinMode(UP_PIN, INPUT);
-  pinMode(RIGHT_PIN, INPUT);
-  pinMode(DOWN_PIN, INPUT);
+void trackball_init(DEVTERM *dv)
+{
+    // Enable trackball pins
+    pinMode(LEFT_PIN, INPUT);
+    pinMode(UP_PIN, INPUT);
+    pinMode(RIGHT_PIN, INPUT);
+    pinMode(DOWN_PIN, INPUT);
+
+    // Initialize filters
+#ifdef USE_FIR
+    init_fir();
+    fir_init(&fir_x, FILTER_SIZE, fir_coeffs);
+    fir_init(&fir_y, FILTER_SIZE, fir_coeffs);
+#endif
+#ifdef USE_IIR
+    iir_init(&iir_x, IIR_SIZE, iir_coeffs_b, IIR_SIZE, iir_coeffs_a);
+    iir_init(&iir_y, IIR_SIZE, iir_coeffs_b, IIR_SIZE, iir_coeffs_a);
+#endif
+
+    // Run interrupt function when corresponding PIN changes its value
+    attachInterrupt(LEFT_PIN, &interrupt<PIN_LEFT>, ExtIntTriggerMode::CHANGE);
+    attachInterrupt(RIGHT_PIN, &interrupt<PIN_RIGHT>, ExtIntTriggerMode::CHANGE);
+    attachInterrupt(UP_PIN, &interrupt<PIN_UP>, ExtIntTriggerMode::CHANGE);
+    attachInterrupt(DOWN_PIN, &interrupt<PIN_DOWN>, ExtIntTriggerMode::CHANGE);
 
-  attachInterrupt(LEFT_PIN, &interrupt<AXIS_X,-1> , ExtIntTriggerMode::CHANGE);
-  attachInterrupt(RIGHT_PIN, &interrupt<AXIS_X, 1>, ExtIntTriggerMode::CHANGE);
-  attachInterrupt(UP_PIN, &interrupt<AXIS_Y, -1>, ExtIntTriggerMode::CHANGE);
-  attachInterrupt(DOWN_PIN, &interrupt<AXIS_Y, 1>, ExtIntTriggerMode::CHANGE);
-  
 }