added advanced leds demo (#301)

Author: EricPobot

demo/misc/leds.py

@@ -0,0 +1,82 @@
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+
+# ------------------------------------------------------------------------------
+# Copyright (c) 2015 Eric Pascual
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in
+# all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NON INFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+# THE SOFTWARE.
+# -----------------------------------------------------------------------------
+
+""" This demo illustrates how to use the two red-green LEDs of the EV3 brick.
+"""
+
+import time
+import math
+
+from ev3dev.ev3 import Leds
+
+print(__doc__.lstrip())
+
+print('saving current LEDs state')
+
+# save current state
+saved_state = [led.brightness_pct for led in Leds.LEFT + Leds.RIGHT]
+
+Leds.all_off()
+time.sleep(1)
+
+# cycle LEDs like a traffic light
+print('traffic light')
+for _ in range(3):
+    for color in (Leds.GREEN, Leds.YELLOW, Leds.RED):
+        for group in (Leds.LEFT, Leds.RIGHT):
+            Leds.set_color(group, color)
+        time.sleep(0.5)
+
+Leds.all_off()
+time.sleep(0.5)
+
+# blink LEDs from side to side now
+print('side to side')
+for _ in range(3):
+    for led in (Leds.red_left, Leds.red_right, Leds.green_left, Leds.green_right):
+        led.brightness_pct = 100
+        time.sleep(0.5)
+        led.brightness_pct = 0
+
+Leds.all_off()
+time.sleep(0.5)
+
+# continuous mix of colors
+print('colors fade')
+for i in range(360):
+    rd = math.radians(10 * i)
+    Leds.red_left.brightness_pct = .5 * (1 + math.cos(rd))
+    Leds.green_left.brightness_pct = .5 * (1 + math.sin(rd))
+    Leds.red_right.brightness_pct = .5 * (1 + math.sin(rd))
+    Leds.green_right.brightness_pct = .5 * (1 + math.cos(rd))
+    time.sleep(0.05)
+
+Leds.all_off()
+time.sleep(0.5)
+
+print('restoring initial LEDs state')
+for led, level in zip(Leds.RIGHT + Leds.LEFT, saved_state) :
+    led.brightness_pct = level
+