Feature/TouchSensor

docs/api.rst

@@ -117,6 +117,14 @@ MotionSensor
     :inherited-members:
     :members: 
 
+TouchSensor
+-----------
+
+.. autoclass:: TouchSensor
+    :show-inheritance:
+    :inherited-members:
+    :members: 
+
 Switch
 ------
 

docs/changelog.rst

@@ -22,6 +22,7 @@ Change log
 -----------
 
 + Introduced ``MotionSensor`` class for PIR sensors
++ Introduced ``TouchSensor`` class for capacitive touch sensors
 
 0.4.2 - 2023-05-12
 ------------------

docs/examples/touch_sensor.py

@@ -0,0 +1,12 @@
+from picozero import TouchSensor, pico_led
+from time import sleep
+
+# Capacitive touch sensor output connected to pin 2
+touch = TouchSensor(2)
+
+while True:
+    if touch.is_touched:
+        pico_led.on()
+    else:
+        pico_led.off()
+    sleep(0.1)

docs/examples/touch_sensor_callbacks.py

@@ -0,0 +1,15 @@
+from picozero import TouchSensor, pico_led
+from time import sleep
+
+touch = TouchSensor(2)
+
+# Set up event callbacks
+touch.when_touched = pico_led.on
+touch.when_touch_ends = pico_led.off
+
+# Keep the program running
+try:
+    while True:
+        sleep(1)
+except KeyboardInterrupt:
+    pico_led.off()  # Make sure LED is off when exiting

docs/recipes.rst

@@ -145,6 +145,17 @@ Turn the :obj:`pico_led` on when a :class:`Button` is pressed and off when it is
 
 .. literalinclude:: examples/button_led.py
 
+Touch sensor
+------------
+
+Detect touch using a capacitive touch sensor:
+
+.. literalinclude:: examples/touch_sensor.py
+
+Use callbacks to respond to touch events:
+
+.. literalinclude:: examples/touch_sensor_callbacks.py
+
 Motion sensor
 -------------
 

picozero/__init__.py

@@ -25,6 +25,7 @@
     Switch,
     Button,
     MotionSensor,
+    TouchSensor,
     AnalogInputDevice,
     Potentiometer,
     Pot,

picozero/picozero.py

@@ -2359,6 +2359,36 @@ def __init__(self, pin, pull_up=False, bounce_time=1.00):
 MotionSensor.when_no_motion = MotionSensor.when_deactivated
 
 
+class TouchSensor(Button):
+    """
+    Represents a capacitive touch sensor (e.g. TTP223)
+
+    :param int pin:
+        The pin that the capacitive touch sensor is connected to.
+
+    :param bool pull_up:
+        If :data:`True`, the device will be pulled up to
+        HIGH. If :data:`False` (the default), the device will be pulled down to LOW.
+        Most capacitive touch sensors work with pull_up=False.
+
+    :param float bounce_time:
+        The bounce time for the device. If set, the device will ignore
+        any touch events that happen within the bounce time after a
+        touch event. This is useful to prevent false triggers from
+        electrical noise or multiple rapid touches.
+        Defaults to 0.02 seconds.
+    """
+
+    def __init__(self, pin, pull_up=False, bounce_time=0.02):
+        super().__init__(pin=pin, pull_up=pull_up, bounce_time=bounce_time)
+
+
+TouchSensor.is_touched = TouchSensor.is_active
+TouchSensor.is_not_touched = TouchSensor.is_inactive
+TouchSensor.when_touch_starts = TouchSensor.when_activated
+TouchSensor.when_touch_ends = TouchSensor.when_deactivated
+
+
 class AnalogInputDevice(InputDevice, PinMixin):
     """
     Represents a generic input device with analogue functionality, e.g.