refactor var names and improve docs

analog_input.h

@@ -35,19 +35,19 @@ class AnalogInput {
     void Process() {
         old_read_ = read_;
         int raw = analogRead(pin_);
-        read_ = map(raw, calibration_offset_, MAX_INPUT, calibration_low_, calibration_high_);
+        read_ = map(raw, offset_, MAX_INPUT, low_, high_);
     }
 
     // Set calibration values.
 
-    void AdjustCalibrationLow(int val) { calibration_low_ += val; }
-    void AdjustCalibrationOffset(int val) { calibration_offset_ += val; }
-    void AdjustCalibrationHigh(int val) { calibration_high_ += val; }
+    void AdjustCalibrationLow(int amount) { low_ += amount; }
+    void AdjustCalibrationOffset(int amount) { offset_ += amount; }
+    void AdjustCalibrationHigh(int amount) { high_ += amount; }
 
     /**
      * @brief Get the current value of the analog input within a range of +/-512.
      * 
-     * @return InputState 
+     * @return read value within a range of +/-512.
      */
     inline int16_t Read() { return read_; }
 
@@ -55,9 +55,10 @@ class AnalogInput {
     uint8_t pin_;
     int16_t read_;
     uint16_t old_read_;
-    int calibration_offset_ = 0;
-    int calibration_low_ = -512;
-    int calibration_high_ = 512;
+    // calibration values.
+    int offset_ = 0;
+    int low_ = -512;
+    int high_ = 512;
 };
 
 #endif