Merge pull request #198 from EAGrahamJr/servo-trim

Allows ServoTrim to set 0 to X arc for the motor.

diozero-core/src/main/java/com/diozero/api/ServoTrim.java

@@ -5,7 +5,7 @@
  * Organisation: diozero
  * Project: diozero - Core
  * Filename: ServoTrim.java
- * 
+ *
  * This file is part of the diozero project. More information about this project
  * can be found at https://www.diozero.com/.
  * %%
@@ -17,10 +17,10 @@
  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  * copies of the Software, and to permit persons to whom the Software is
  * furnished to do so, subject to the following conditions:
- * 
+ *
  * The above copyright notice and this permission notice shall be included in
  * all copies or substantial portions of the Software.
- * 
+ *
  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
@@ -62,6 +62,9 @@ public class ServoTrim {
  private static final int MG996R_RANGE_US = 2_000;
  public static final ServoTrim MG996R = new ServoTrim(DEFAULT_MID_US, DEFAULT_90_DELTA_US, MG996R_RANGE_US);
 
+ // Metal-gear micro servo ("size-compatible" with an SG90) but with an extended range
+ public static final ServoTrim MG90S = new ServoTrim(400,2600,200L);
+
  private final int midPulseWidthUs;
  private final int ninetyDegPulseWidthUs;
  private final int minPulseWidthUs;
@@ -81,11 +84,40 @@ public ServoTrim(int midPulseWidthUs, int ninetyDegPulseWidthUs) {
  this(midPulseWidthUs, ninetyDegPulseWidthUs, 2 * ninetyDegPulseWidthUs);
  }
 
+ /**
+ * Assumes 180 degree range of movement
+ *
+ * @param midPulseWidthUs Pulse width in microseconds corresponding to the
+ * centre position (90 degrees)
+ * @param ninetyDegPulseWidthUs Pulse width in microseconds corresponding to a
+ * 90 degree movement in either direction
+ * @param rangePulseWidthUs Pulse width in microseconds corresponding to the range
+ * of motion in either direction (this is subtracted from
+ * the 90 degree value
+ */
  public ServoTrim(int midPulseWidthUs, int ninetyDegPulseWidthUs, int rangePulseWidthUs) {
  this(midPulseWidthUs, ninetyDegPulseWidthUs, midPulseWidthUs - rangePulseWidthUs / 2,
  midPulseWidthUs + rangePulseWidthUs / 2);
  }
 
+ /**
+ * Assumes 180 degree range of movement.
+ * <p>
+ * Note: if the min/max pulse widths exceed the
+ * mid-point +/- the 90 degree mark, value for min/max angles <b>may</b> be out of the
+ * 0-180 range.
+ * </p>
+ *
+ * @param midPulseWidthUs Pulse width in microseconds corresponding to the
+ * centre position (90 degrees)
+ * @param ninetyDegPulseWidthUs Pulse width in microseconds corresponding to a
+ * 90 degree movement in either direction
+ * @param minPulseWidthUs Pulse width in microseconds corresponding to the minimum
+ * rotation location (see description)
+ * @param maxPulseWidthUs Pulse width in microseconds corresponding to the maximum
+ * rotation location (see description)
+ * @see ServoTrim#MG996R
+ */
  public ServoTrim(int midPulseWidthUs, int ninetyDegPulseWidthUs, int minPulseWidthUs, int maxPulseWidthUs) {
  this.midPulseWidthUs = midPulseWidthUs;
  this.ninetyDegPulseWidthUs = ninetyDegPulseWidthUs;
@@ -97,6 +129,32 @@ public ServoTrim(int midPulseWidthUs, int ninetyDegPulseWidthUs, int minPulseWid
  midPulseWidthUs + ninetyDegPulseWidthUs, 0, 180, false);
  }
 
+ /**
+ * Assumes minimum value is assigned to 0 degrees and the maximum value is associated with the full arc.
+ * <p>
+ * Note: the arc parameter is defined as a <b>long</b> to avoid conflicts with the other constructor(s).
+ * </p>
+ *
+ * @param minPulseWidthUs Pulse width in microseconds corresponding to the minimum
+ * rotation location, or 0 degrees
+ * @param maxPulseWidthUs Pulse width in microseconds corresponding to the maximum
+ * rotation location, aka {@code arcDegrees}
+ * @param arcDegrees How far the servo rotates when {@code maxPulseWidthUs} is applied.
+ */
+ public ServoTrim(int minPulseWidthUs, int maxPulseWidthUs, long arcDegrees) {
+ minAngle = 0;
+ maxAngle = (int)arcDegrees;
+ this.minPulseWidthUs = minPulseWidthUs;
+ this.maxPulseWidthUs = maxPulseWidthUs;
+
+ // calculate everything else
+ int pulseRange = maxPulseWidthUs - minPulseWidthUs;
+ this.midPulseWidthUs = Math.round(pulseRange / 2f) + minPulseWidthUs;
+
+ float ninetyLocation = 90f / arcDegrees;
+ this.ninetyDegPulseWidthUs = Math.round(ninetyLocation * pulseRange) + minPulseWidthUs;
+ }
+
  public int getMidPulseWidthUs() {
  return midPulseWidthUs;
  }