Electric Dollar Store

LED is a “Smart LED”, a bright LED emitter with color completely under software control. You can use it for indicators at low brightness and console lighting at full brightness. LED uses a bright, clear, flicker-free RGB LED that is controlled over I²C using a straightforward write-only protocol. Up to 8 LEDs can share an I²C bus under completely independent control.

LED uses 16-bit per channel high-speed PWM to drive each color channel. The output is gamma-corrected so that the increase in brightness s smooth over the entire 1-255 value range.

LED has two commands: an instantaneous "set color" command, which specifies the red, green and blue color byte values:

0x00
<red>
<green>
<blue>

and a fade command for smooth color transitions:

0x01
<red>
<green>
<blue>
<time>

where <time> is the fade duration in units of 1/30th of a second. For example 15 gives a fade time of a half second, and 60 gives a fade time of two seconds. 

import sys
import serial
import time
import struct
import random

from i2cdriver import I2CDriver, EDS

if __name__ == '__main__':
    i2 = I2CDriver(sys.argv[1])

    d = EDS.LED(i2)
    TEAL    = 0x008080
    ORANGE  = 0xffa500
    while 1:
        time.sleep(1)
        d.hex(TEAL, 3)
        time.sleep(1)
        d.hex(ORANGE, 3)

#include <Wire.h>

// Set the color to (r,g,b). Each is a byte 0-255.
// If t is nonzero, the change happens over t/30 seconds.
// For example if t is 15 the color fades over a half-second.

void led(byte r, byte g, byte b, byte t = 0)
{
  Wire.beginTransmission(0x08);
  Wire.write((t == 0) ? 0x00 : 0x01);
  Wire.write(r);
  Wire.write(g);
  Wire.write(b);
  if (t != 0)
    Wire.write(t);
  Wire.endTransmission();
}

// Set the color to hhh, a 24-bit RGB color.
// If t is nonzero, the change happens over t/30 seconds.
// For example if t is 15 the color fades over a half-second.

void led(uint32_t hhh, byte t = 0)
{
  led(hhh >> 16, hhh >> 8, hhh, t);
}

#define TEAL    0x008080L
#define ORANGE  0xffa500L

void setup() {
  Wire.begin();
}

void loop() {
  delay(1000);
  led(TEAL, 3);
  delay(1000);
  led(ORANGE, 3);
}

from machine import I2C
import time

class LED:
    """ LED is an RGB LED """
    def __init__(self, i2, a = 0x08):
        self.i2 = i2
        self.a = a

    def rgb(self, r, g, b, t = 0):
        """
        Set the color to (r,g,b). Each is a byte 0-255.
        If t is nonzero, the change happens over t/30 seconds.
        For example if t is 15 the color fades over a half-second.
        """
        if t == 0:
            self.i2.writeto(self.a, bytes((0, r, g, b)))
        else:
            self.i2.writeto(self.a, bytes((1, r, g, b, t)))
        
    def hex(self, hhh, t = 0):
        """
        Set the color to hhh, a 24-bit RGB color.
        If t is nonzero, the change happens over t/30 seconds.
        For example if t is 15 the color fades over a half-second.
        """
        r = (hhh >> 16) & 0xff
        g = (hhh >> 8) & 0xff
        b = hhh & 0xff
        self.rgb(r, g, b, t)


def main():
    i2 = I2C(1, freq = 100000)

    d = LED(i2)
    TEAL    = 0x008080
    ORANGE  = 0xffa500
    while 1:
        time.sleep(1)
        d.hex(TEAL, 3)
        time.sleep(1)
        d.hex(ORANGE, 3)
Default I²C address 0x08 (0b0001000)
Current consumption (typ.) 25 mA
Vcc 3.3 V