Add TouchSensor class for capacitive touch sensors

Author: pjbRPF

docs/api.rst

@@ -109,6 +109,14 @@ MotionSensor
     :inherited-members:
     :members: 
 
+TouchSensor
+-----------
+
+.. autoclass:: TouchSensor
+    :show-inheritance:
+    :inherited-members:
+    :members: 
+
 Switch
 ------
 

docs/examples/touch_sensor.py

@@ -0,0 +1,13 @@
+from picozero import TouchSensor
+from time import sleep
+
+touch = TouchSensor(2)
+
+print("Touch the sensor...")
+
+while True:
+    if touch.is_touched:
+        print("Touch detected!")
+    else:
+        print("No touch")
+    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

picozero/__init__.py

@@ -1,43 +1,36 @@
 __name__ = "picozero"
 __package__ = "picozero"
-__version__ = '0.4.2'
+__version__ = "0.4.2"
 __author__ = "Raspberry Pi Foundation"
 
 from .picozero import (
     PWMChannelAlreadyInUse,
     EventFailedScheduleQueueFull,
-
     pinout,
-
     DigitalOutputDevice,
     DigitalLED,
     Buzzer,
     PWMOutputDevice,
     PWMLED,
     LED,
     pico_led,
-    
     PWMBuzzer,
     Speaker,
-
     RGBLED,
     Motor,
     Robot,
     Servo,
-    
     DigitalInputDevice,
     Switch,
     Button,
     MotionSensor,
-
+    TouchSensor,
     AnalogInputDevice,
     Potentiometer,
     Pot,
-
     TemperatureSensor,
     pico_temp_sensor,
     TempSensor,
     Thermistor,
-
     DistanceSensor,
 )

picozero/picozero.py

@@ -2027,6 +2027,35 @@ def __init__(self, pin, pull_up=False, bounce_time=1.00):
 MotionSensor.when_motion = MotionSensor.when_activated
 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
+# Note: No alias for is_inactive - use 'not touch.is_touched' for clarity
+TouchSensor.when_touched = TouchSensor.when_activated
+TouchSensor.when_touch_ends = TouchSensor.when_deactivated
+
 
 class AnalogInputDevice(InputDevice, PinMixin):
     """