piripherals.led module

Things that have to do with controlling LEDs

class piripherals.led.NeoPixels(*args, **kwargs)

Bases: object

an interface to NeoPixel LEDs based on rpi_ws281x.

This wraps around PixelStrip and adds additional functionality, especially asynchronous animation support.

Constructor arguments are passed to PixelStrip.

Parameters:

• num (int) – # of LEDs on the strip
• pin (int) – BCM pin number of data pin. not all pins are allowed, see pin usage information of rpi_ws281x.

animate(func, atexit=None, freq=1, period=0, timeout=0, cycles=0, fade=0, delay=0.01, wait=False)

asynchronous animation

The animation is executed on a separate thread. The animation is stopped, when any function, that changes the state of the LEDs, is called. The animation is defined in func. This function gets passed 3 arguments:

• p - raw PixelStrip, call methods of this to manipulate the LEDs,

  which results in the animation

• s - normalized time in [0,1] in animation period, use this

  to create cyclic animations

• t - time in seconds since startof animation

func is called repeatedly with delay between the calls.

Parameters:

• func (callable(p,s,t)) – animation function
• atexit (callable()) – exit hook, function to call after animation
• freq (float) – animation frequency in Hz
• period (float) – animation period in seconds (freq=1/period), give either freq or period, period has higher priority
• timeout (float) – animation duration in seconds
• cycles (float) – animation cycle count, (timeout=cycles/freq) give either timeout or cycles, cycles has higher priority
• fade (float) – fade out animation over this number of seconds (sets timeout=fade)
• delay (float) – delay in seconds between calls of func
• wait (bool) – wait for animation to finish, synchronous animation, requires timeout

blink(pattern='10', fade=0, color=None, **kwargs)

blink LEDs on strip with given blink pattern.

Parameters:

• pattern (str) – the blink pattern, that is played back in each
• period. It is either a str of 1 and 0 without space, (animation) –
• a str with space separated float brightness values. (or) –

for other args see animate()

breathe(n=1, fade=0, color=None, **kwargs)

brightness breathing animation.

This was inspired by http://sean.voisen.org/blog/2011/10/breathing-led-with-arduino/.

Parameters:

• n (float) – nonlinearity of brightness function
• color (tuple(r,g,b)) – color set on animation start

for other args see animate()

brightness(b=1)

set brightness, affects all LEDs

Parameters:b (float) – brightness in range [0,1]

clock(secs=1, **kwargs)

a clock.

Works best on a circular strip with 12 LEDs. Hours are red, minutes are green, seconds are blue.

Parameters:secs (int) – show blue seconds 0 = do not show seconds, 1 = show blue seconds, 2 = flash white seconds in 12th position, 3 = run white seconds around in loop

for other args see animate()

color(led=None, r=0, g=-1, b=-1, v=-1)

set color

Parameters:

• led (int) – # of LED on strip to set the color for, None = all LEDs
• r (float) – red value from range [0,1], if not given r = 0
• g (float) – green value from range [0,1], if not given g = r
• b (float) – blue value from range [0,1], if not given b = g
• v (float) – brightness, see brightness(), is applied to all LEDs

rainbow(**kwargs)

rotating rainbow animation, for args see animate()

sequence(colors=[(1, 0, 0), (0.5, 0.5, 0), (0, 1, 0), (0, 0.5, 0.5), (0, 0, 1), (0.5, 0, 0.5)], **kwargs)

animate first LED with given sequence of colors.

Parameters:colors ([(r,g,b),..]) – sequence of colors

for other args see animate()