Make pretty colors with Arduino and NeoPixels.
The project depends on headers for the Adafruit NeoPixel, available at the @adafruit GitHub repository, and (for light sensing) the Adafruit TSL2561 library also provided by @adafruit.
This code was written for the Adafruit FLORA wearable Arduino, but it should work on any Arduino capable of addressing the NeoPixel PCBs - see the Adafruit docuemntation for up-to-date information.
This code expects NeoPixels to be connected on pin 6. If a different output pin is desired,
simply change the definition of PIN at the top of coruscate.ino.
If brightness sensing is desired, a TSL2561 module should
be connected to the I2C SCL and SDA pins; see your Arduino documentation for the locations of these pins.
If no TSL2561 is detected, coruscate.ino will set the NeoPixel brightness to DEFAULT_BRIGHTNESS .
PIN is the digital output to which the strip of NeoPixels is connected. Set this according to your physical hardware setup.
ONBOARD_ERROR_LED will blink if there is a problem detecting the TSL2561. Set this to an unused pin if TSL2561
is not in use or debug output is not desired.
RANDOM_SEED_PIN will be read on startup to seed the random number generator. Any ungrounded analog pin will
work well.
MINIMUM_LUX sets a floor on the brightness of the NeoPixel LEDs - even if very little ambient light is detected,
the LEDs will always be at least MINIMUM_LUX bright.
DEFAULT_BRIGHTNESS sets the brightness for NeoPixels if there is no TSL2561, or the TSL2561 can't be read.
(Failure to read the TSL2561 often results from either total darkness or complete saturation, situations
which are unfortunately indistinguishable; I chose to handle this by setting DEFAULT_BRIGHTNESS relatively high.)
MAXIMUM_DRIFT controls the maximum change in a red, green, or blue (independently) per change cycle. Valid values are 0 (never change the color) to 255 (allow any amount of change).
TWEEN_CONSTANT controls the speed of the change between randomly-chosen colors. Set this number high to get slow changes with many intermediate gradations; set it low to get quick transitions with few frames between them.