analog pwm output example

add configurable channel to analog_output example

catch prev. values

fixup analog_out

Author: brentru

examples/basics/analog_output.py

@@ -0,0 +1,72 @@
+"""
+`analog_output.py`
+-------------------
+PWM a LED from
+Adafruit IO!
+
+Requires:
+    - Adafruit-Blinka
+    - Adafruit-CircuitPython-PCA9685
+"""
+# import system libraries
+import time
+
+# import Adafruit Blinka
+from board import SCL, SDA
+from busio import I2C
+
+# import the PCA9685 module.
+from adafruit_pca9685 import PCA9685
+
+# import Adafruit IO REST client
+from Adafruit_IO import Client, Feed, RequestError
+
+# Set to your Adafruit IO key.
+# Remember, your key is a secret,
+# so make sure not to publish it when you publish this code!
+ADAFRUIT_IO_KEY = 'YOUR_IO_KEY'
+
+# Set to your Adafruit IO username.
+# (go to https://accounts.adafruit.com to find your username)
+ADAFRUIT_IO_USERNAME = 'YOUR_IO_USERNAME'
+
+# Create the I2C bus interface.
+i2c_bus = I2C(SCL, SDA)
+
+# Create a simple PCA9685 class instance.
+pca = PCA9685(i2c_bus)
+PCA_CHANNEL = 4
+
+# Set the PWM frequency to 60hz.
+pca.frequency = 60
+prev_read = 0
+
+# Create an instance of the REST client.
+aio = Client(ADAFRUIT_IO_USERNAME, ADAFRUIT_IO_KEY)
+
+try: # if we have a 'analog' feed
+    analog = aio.feeds('analog')
+except RequestError: # create an `analog` feed
+    feed = Feed(name='analog')
+    analog = aio.create_feed(feed)
+
+
+def map_range(x, in_min, in_max, out_min, out_max):
+    """re-maps a number from one range to another."""
+    mapped = (x-in_min) * (out_max - out_min) / (in_max-in_min) + out_min
+    if out_min <= out_max:
+        return max(min(mapped, out_max), out_min)
+    return min(max(mapped, out_max), out_min)
+
+while True:
+    # grab the `analog` feed value
+    analog_read = aio.receive(analog.key)
+    if analog_read.value != prev_read:
+        print('received <- ', analog_read.value)
+        # map the analog value from 0 - 1023 to 0 - 65534
+        analog_value = map_range(int(analog_read.value), 0, 1024, 0, 65534)
+        # set the LED to the mapped feed value
+        pca.channels[PCA_CHANNEL].duty_cycle = int(analog_value)
+    prev_read = analog_read.value
+    # timeout so we don't flood IO with requests
+    time.sleep(0.5)