Add dead zone to knobs

software/firmware/europi.py

@@ -128,17 +128,18 @@ class AnalogueReader:
     not need to be used by user scripts.
     """
 
-    def __init__(self, pin, samples=DEFAULT_SAMPLES):
+    def __init__(self, pin, samples=DEFAULT_SAMPLES, deadzone=0.0):
         self.pin_id = pin
         self.pin = ADC(Pin(pin))
         self.set_samples(samples)
+        self.deadzone = deadzone
 
     def _sample_adc(self, samples=None):
         # Over-samples the ADC and returns the average.
-        values = []
+        value = 0
         for _ in range(samples or self._samples):
-            values.append(self.pin.read_u16())
-        return round(sum(values) / len(values))
+            value += self.pin.read_u16()
+        return round(value / (samples or self._samples))
 
     def set_samples(self, samples):
         """Override the default number of sample reads with the given value."""
@@ -148,7 +149,9 @@ def set_samples(self, samples):
 
     def percent(self, samples=None):
         """Return the percentage of the component's current relative range."""
-        return self._sample_adc(samples) / MAX_UINT16
+        value = self._sample_adc(samples) / MAX_UINT16
+        value = value * (1.0 + 2.0 * self.deadzone) - self.deadzone
+        return max(0.0, min(1.0, value))
 
     def range(self, steps=100, samples=None):
         """Return a value (upper bound excluded) chosen by the current voltage value."""
@@ -255,12 +258,12 @@ def clock_division(self):
     """
 
     def __init__(self, pin):
-        super().__init__(pin)
+        super().__init__(pin, deadzone=0.01)
 
     def percent(self, samples=None):
         """Return the knob's position as relative percentage."""
         # Reverse range to provide increasing range.
-        return 1 - (self._sample_adc(samples) / MAX_UINT16)
+        return 1.0 - super().percent(samples)
 
     def read_position(self, steps=100, samples=None):
         """Returns the position as a value between zero and provided integer."""

software/tests/experimental/test_knobs.py

@@ -258,9 +258,9 @@ def test_access_by_index(mockHardware: MockHardware, knob_bank: KnobBank):
     mockHardware.set_ADC_u16_value(knob_bank.current, MAX_UINT16 / 5)
 
     assert round(knob_bank.knobs[0].percent(), 2) == 0
-    assert round(knob_bank.knobs[1].percent(), 2) == 0.80
+    assert round(knob_bank.knobs[1].percent(), 2) == 0.81
     assert round(knob_bank.knobs[2].percent(), 2) == 0.67
-    assert round(knob_bank.current.percent(), 2) == 0.80
+    assert round(knob_bank.current.percent(), 2) == 0.81
 
 
 # KnobBank.Builder tests

software/tests/test_knob.py

@@ -9,8 +9,8 @@
     "value, expected",
     [
         (1, 1.0000),
-        (0.75, 0.7500),
-        (0.66, 0.6600),
+        (0.75, 0.7550),
+        (0.66, 0.6632),
         (0.5, 0.5000),
         (0, 0.0000),
     ],
@@ -25,8 +25,8 @@ def test_set_knob_percent(mockHardware: MockHardware, value, expected):
     "value, expected",
     [
         (0, 1.0000),
-        (MAX_UINT16 / 4, 0.7500),
-        (MAX_UINT16 / 3, 0.6667),
+        (MAX_UINT16 / 4, 0.7550),
+        (MAX_UINT16 / 3, 0.6700),
         (MAX_UINT16 / 2, 0.5000),
         (MAX_UINT16, 0.0000),
     ],
@@ -41,8 +41,8 @@ def test_percent(mockHardware: MockHardware, value, expected):
     "value, expected",
     [
         (0, 99),
-        (MAX_UINT16 / 4, 74),
-        (MAX_UINT16 / 3, 66),
+        (MAX_UINT16 / 4, 75),
+        (MAX_UINT16 / 3, 67),
         (MAX_UINT16 / 2, 49),
         (MAX_UINT16, 0),
     ],