Share your code. npm Orgs help your team discover, share, and reuse code. Create a free org »

    leddriverpublic

    node-leddriver

    This is a node.js library to control a SPI led driver.

    I wrote this to control my Adafruit 24-Channel 12-bit PWM LED Driver using the TLC5947 with my Raspberry Pi. This should also work with different SPI devices or host systems but my examples referr to this configuration. It could also be used for other PWM modules like motor controls etc.

    installation

    npm install leddriver

    initialization

    var LEDDRIVER = require("leddriver");
    var driver = new LEDDRIVER(24, 12);

    parameters:

    • the number of channels your leddriver has
    • the bits per channel of your leddriver
    • (optional) the name of the SPI device (if omitted /dev/spidev0.0 as defined in node-simplespi )

    directly setting values

    driver.set(5, 819);

    parameters:

    • the channelnumber to set (0 to number of channels - 1)
    • the direct value to set in the channel

    This example sets the value of channel 5 to 500. The maximum allowed value depends on the bits per channel of your device. Since I am using a 12bit SPI device it has 3 hexadecimal digits per channel ("000" to "FFF"). In decimal this is a value between 0 and 4095.

    percentage value setting

    driver.pset(5, 0.2);
    • the channelnumber to set (0 to number of channels - 1)
    • the percentage to set in the channel (0 - 1)

    This example sets the value of channel 5 to 0.2 * maximum value. In my 12bit example this has exactly the same result like the first example (0.2 * 4095 = 819) but it is far easier to use like this.

    sending the values to your driver

    driver.send();

    This updates your led driver by sending the values.

    example

    var LEDDRIVER = require("leddriver");
    var driver = new LEDDRIVER(24, 12);
     
    driver.pset(0, 1);
    driver.pset(1, 0);
    driver.pset(2, 1);
    driver.send();
     
    setTimeout(function() {
     
        driver.pset(0, 0.5);
        driver.pset(1, 0.5);
        driver.pset(2, 0.5);
        driver.send();
     
    }, 5000);

    When running this example the LEDs connected to channel 0 and 2 should be fully turned on while channel 1 is off. After 5 seconds all the LEDs go to half brightness.

    setting RGB-LEDs

    The library also includes a helper for setting RGB-LEDs to a color defined in csslike hex style:

    driver.setRGB("#e010ff", 0, 1, 2);

    parameters:

    • the color to set as hexcode
    • the channel of the red LED
    • the channel of the green LED
    • the channel of the blue LED
    • (optional) the channel of the second blue LED

    Special issues with MOSFETS

    When driving with MOSFETS like discussed in the adafruit Forums you should invert (1=0, 0=1) your output. You can turn on inversion of setRGB:

    driver.invert();

    thx @ jnovack

    wiring the Raspberry Pi (example with adafruit led driver)

    Connect your Pi like this to the LED driver:

    Raspberry Pi led driver
    GND GND
    5V or 3.3V (or external) input V+
    SCLK input CLK
    MOSI input DIN
    CE0 input LAT

    Connect /OE on the LED driver to GND or to a GPIO of your choice (you can quickly turn off all LEDs by using a GPIO).

    The SPI interface requires root access on the Raspberry Pi. Run your app with sudo! For more details on getting SPI to run see node-simplespi!

    I am not responsible for any damages to your hardware. Use this at your own risk.

    Keywords

    none

    install

    npm i leddriver

    Downloadsweekly downloads

    6

    version

    0.0.3

    license

    none

    repository

    githubgithub

    last publish

    collaborators

    • avatar