add gamma correct

Author: ladyada

examples/espatcontrol_cheerlights.py

@@ -0,0 +1,107 @@
+"""
+This example will query ThingSpeak channel 1417 "CheerLights" and display the
+color on a NeoPixel ring or strip
+"""
+import gc
+import time
+import board
+import busio
+from digitalio import DigitalInOut
+from Adafruit_CircuitPython_ESP_ATcontrol import adafruit_espatcontrol
+import neopixel
+import ujson
+import adafruit_fancyled.adafruit_fancyled as fancy
+
+
+
+# Get wifi details and more from a settings.py file
+try:
+    from settings import settings
+except ImportError:
+    print("WiFi settings are kept in settings.py, please add them there!")
+    raise
+
+#              CONFIGURATION
+TIME_BETWEEN_QUERY = 10  # in seconds
+
+# Cheerlights!
+DATA_SOURCE = "http://api.thingspeak.com/channels/1417/feeds.json?results=1"
+DATA_LOCATION = ["feeds", 0, "field2"]
+
+uart = busio.UART(board.TX, board.RX, timeout=0.1)
+resetpin = DigitalInOut(board.D5)
+rtspin = DigitalInOut(board.D9)
+
+# Create the connection to the co-processor and reset
+esp = adafruit_espatcontrol.ESP_ATcontrol(uart, 115200, run_baudrate=460800,
+                                          reset_pin=resetpin,
+                                          rts_pin=rtspin, debug=True)
+esp.hard_reset()
+
+# neopixels
+pixels = neopixel.NeoPixel(board.A1, 16, brightness=0.3)
+pixels.fill(0)
+builtin = neopixel.NeoPixel(board.NEOPIXEL, 1, brightness=0.1)
+builtin[0] = 0
+
+# we'll save the value in question
+last_value = value = None
+the_time = None
+times = 0
+
+def get_value(response, location):
+    """Extract a value from a json object, based on the path in 'location'"""
+    try:
+        print("Parsing JSON response...", end='')
+        json = ujson.loads(response)
+        print("parsed OK!")
+        for x in location:
+            json = json[x]
+        return json
+    except ValueError:
+        print("Failed to parse json, retrying")
+        return None
+
+while True:
+    try:
+        while not esp.is_connected:
+            builtin[0] = (100, 0, 0)
+            # settings dictionary must contain 'ssid' and 'password' at a minimum
+            esp.connect(settings)
+        builtin[0] = (0, 100, 0)
+        # great, lets get the data
+        print("Retrieving data source...", end='')
+        builtin[0] = (100, 100, 0)
+        header, body = esp.request_url(DATA_SOURCE)
+        builtin[0] = (0, 0, 100)
+        print("Reply is OK!")
+    except (RuntimeError, adafruit_espatcontrol.OKError) as e:
+        print("Failed to get data, retrying\n", e)
+        continue
+    print('-'*40, "Size: ", len(body))
+    print(str(body, 'utf-8'))
+    print('-'*40)
+    # For mystery reasons, there's two numbers before and after the json data
+    lines = body.split(b'\r\n')  # so split into lines
+    value = get_value(lines[1], DATA_LOCATION) # an get the middle chunk
+    builtin[0] = (100, 100, 100)
+    if not value:
+        continue
+    print(times, the_time, "value:", value)
+
+    if last_value != value:
+        color = int(value[1:],16)
+        red = color >> 16 & 0xFF
+        green = color >> 8 & 0xFF
+        blue = color& 0xFF
+        gamma_corrected = fancy.gamma_adjust(fancy.CRGB(red, green, blue)).pack()
+
+        pixels.fill(gamma_corrected)
+        last_value = value
+    times += 1
+
+    # normally we wouldn't have to do this, but we get bad fragments
+    header = body = None
+    gc.collect()
+    print(gc.mem_free())  # pylint: disable=no-member
+    time.sleep(TIME_BETWEEN_QUERY)