Introducing hardware dimmer using analogWrite()

src/Dimmer.h

@@ -5,7 +5,7 @@
  *
  * Author: Balazs Kelemen
  * Contact: prampec+arduino@gmail.com
- * Copyright: 2012 Balazs Kelemen
+ * Copyright: 2020 Balazs Kelemen
  * Copying permission statement:
     This file is part of SoftTimer.
 
@@ -42,7 +42,7 @@ class Dimmer : public Task
     /**
      * We use the SoftPwmTask for dimming.
      *  pwm - The predefined SoftPwm task.
-     *  frequencyMs - Milliseconds will be passed in the OFF->ON->OFF cicle.
+     *  frequencyMs - Milliseconds will be passed in the OFF->ON->OFF cycle.
      *  stepCount - Steps should be perform between a full ON-OFF state.
      */
     Dimmer(SoftPwmTask* pwm, int frequencyMs, byte stepCount = DEFAULT_STEP_COUNT);
@@ -82,7 +82,7 @@ class Dimmer : public Task
     void revertDirection();
 
     /**
-     * Milliseconds will be passed in the OFF->ON->OFF cicle.
+     * Milliseconds will be passed in the OFF->ON->OFF cycle.
      */
     void setFrequency(int frequencyMs);
 

src/HardDimmer.cpp

@@ -0,0 +1,108 @@
+/**
+ * File: HardDimmer.cpp
+ * Description:
+ * SoftTimer library is a lightweight but effective event based timeshare solution for Arduino.
+ *
+ * Author: Balazs Kelemen
+ * Contact: prampec+arduino@gmail.com
+ * Copyright: 2012 Balazs Kelemen
+ * Copying permission statement:
+    This file is part of SoftTimer.
+
+    SoftTimer is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+*/
+
+#include "SoftTimer.h"
+#include "HardDimmer.h"
+
+HardDimmer::HardDimmer(int pwmPin, int frequencyMs) : Task(10, &(HardDimmer::step))
+{
+  this->_pwmPin = pwmPin;
+  this->direction = DIMMER_DIRECTION_HIGH;
+  this->value = 0;
+  pinMode(this->_pwmPin, OUTPUT);
+  this->stepCount = DEFAULT_STEP_COUNT;
+
+  this->setFrequency(frequencyMs);
+}
+
+
+void HardDimmer::startPulsate() {
+  this->stopOnLimit = false;
+  analogWrite(this->_pwmPin, (int)this->value);
+  SoftTimer.add(this);
+}
+
+void HardDimmer::hold() {
+  SoftTimer.remove(this);
+}
+
+void HardDimmer::off() {
+  this->hold();
+  digitalWrite(this->_pwmPin, LOW);
+  SoftTimer.remove(this);
+}
+
+void HardDimmer::revertDirection() {
+  this->direction *= -1;
+}
+
+void HardDimmer::setFrequency(int frequencyMs) {
+  this->_stepLevel = (float)(this->_topLevel - this->_bottomLevel) / (float)this->stepCount;
+  this->periodMicros = (float)frequencyMs * 500.0 / (float)this->stepCount;
+  /*
+  Serial.print("Dimmer");
+  Serial.print(this->_pwmPin);
+  Serial.print(": stepLevel= ");
+  Serial.print(this->_stepLevel);
+  Serial.print(", periodMicros= ");
+  Serial.println(this->periodMicros);
+  */
+}
+
+byte HardDimmer::getUpperLimit() {
+  return 255;
+}
+
+
+void HardDimmer::step(Task* task)
+{
+  HardDimmer* dimmer = (HardDimmer*)task;
+
+  boolean isOnLimit = false;
+
+  dimmer->value += dimmer->direction * dimmer->_stepLevel;
+  if((dimmer->direction < 0) && (dimmer->value < dimmer->_bottomLevel)) {
+    dimmer->value = dimmer->_bottomLevel;
+    dimmer->direction *= -1; // -- next time go in the other direction
+    isOnLimit = true;
+  } else if((dimmer->direction > 0) && (dimmer->value > dimmer->_topLevel)) {
+    dimmer->value = dimmer->_topLevel;
+    dimmer->direction *= -1; // -- next time go in the other direction
+    isOnLimit = true;
+  }
+
+  // Serial.print("Dimmer");
+  // Serial.print(dimmer->_pwmPin);
+  // Serial.print(" = ");
+  // Serial.println((int)dimmer->value);
+  analogWrite(dimmer->_pwmPin, (int)dimmer->value);
+
+  if(isOnLimit && dimmer->stopOnLimit) {
+    SoftTimer.remove(dimmer);
+  }
+
+}
+

src/HardDimmer.h

@@ -0,0 +1,121 @@
+/**
+ * File: HardDimmer.h
+ * Description:
+ * SoftTimer library is a lightweight but effective event based timeshare solution for Arduino.
+ *
+ * Author: Balazs Kelemen
+ * Contact: prampec+arduino@gmail.com
+ * Copyright: 2020 Balazs Kelemen
+ * Copying permission statement:
+    This file is part of SoftTimer.
+
+    SoftTimer is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+*/
+
+#ifndef HARDDIMMER_H
+#define HARDDIMMER_H
+
+#include "Task.h"
+#include "SoftPwmTask.h"
+#include "Arduino.h"
+
+#define DIMMER_DIRECTION_HIGH 1
+#define DIMMER_DIRECTION_LOW -1
+
+#define DEFAULT_STEP_COUNT 8
+
+/**
+ * HardDimmer should be a drop in replacement for Dimmer,
+ * expect for the constructor.
+ */
+class HardDimmer : public Task
+{
+  public:
+    /**
+     * We use the SoftPwmTask for dimming.
+     *  pwm - The predefined SoftPwm task.
+     *  frequencyMs - Milliseconds will be passed in the OFF->ON->OFF cycle.
+     */
+    HardDimmer(int pwmPin, int frequencyMs);
+
+    /**
+     * Start an unlimited pulsation from the current value on, in the current direction.
+     */
+    void startPulsate();
+
+    /**
+     * Hold current PWM value on the output.
+     */
+    void hold();
+
+    /**
+     * Stop PWM, and set output to LOW.
+     */
+    void off();
+
+    /**
+     * Make the dimming to change direction.
+     */
+    void revertDirection();
+
+    /**
+     * Milliseconds will be passed in the OFF->ON->OFF cycle.
+     */
+    void setFrequency(int frequencyMs);
+
+    /**
+     * Get the upper level of the pwm.
+     */
+    byte getUpperLimit();
+
+    void setBottomLevel(byte value = 0) 
+    {
+      this->_bottomLevel = value;
+    }
+    void setTopLevel(byte value = 255) 
+    {
+      this->_topLevel = value;
+    }
+
+    /**
+     * Current dim level PWM value. Note that the value should be between bottomLevel and topLevel.
+     */
+    float value;
+
+    /**
+     * Stop if zero, or pwm->upperLimit is reached.
+     */
+    boolean stopOnLimit;
+
+    /**
+     * Can be one of DIMMER_DIRECTION_HIGH or DIMMER_DIRECTION_LOW.
+     */
+    char direction;
+
+    /**
+     * Level-arranging steps should be performed within each full OFF->ON change. Will be applied if setFrequency() is called.
+     */
+    byte stepCount;
+
+  private:
+    int _pwmPin;
+    float _stepLevel;
+    static void step(Task* me);
+    float _topLevel = 255;
+    float _bottomLevel = 0;
+};
+
+#endif
+