ws2801-connect

    1.2.2 • Public • Published

    WS2801-Connect

    Codacy Badge Coverage Status npm npm npm

    This library contains a javascript class, which represents a WS2801 led stripe connected via SPI. Whereby the SPI implementation is open and not necessarely coupled to the hardware SPI of your controler device of choice.

    Precondition

    The library is implemented in ECMAScript 2015, so your project should support at least this version.

    Installation

    Install it via npm:

    $ npm install ws2801-connect

    Usage

    Start with importing the module via:

    var WS2801 = require("ws2801-connect")

    Create an instance providing the number of led lights and a callback function for the communication with the SPI:

    // 32 led lights, callback with SPI communication
    var leds = new WS2801({ 
       count: 32, 
       spiWrite: (data) => { spi.write(data) }
    })

    The callback gets an array as parameter containing the data to be sent to the SPI and finally to the led stripe. See Examples to get an idea how it works.

    Clear

    Make all led lights black with:

    leds.clear()

    Fill

    Fill all led lights with one color:

    leds.fill("#FF0000") //fill with red
    leds.fill(0, 255, 0) //fill with green
    leds.fill([0x00, 0x00, 0xff]) //fill with blue

    Set single light

    Set the color of a single led light by index (starting with 0):

    leds.setLight(0, "#FF0000") //set first light to red
    leds.setLight(1, 0, 255, 0) //set second light to green
    leds.setLight(2, [0x00, 0x00, 0xff]) //set third light to blue

    Set all lights

    Set possibly all led lights by provided an array with color information:

    // set first three lights with red, green and blue
    leds.setAll([
       [ 255, 0, 0 ],
       "#00ff00",
       "rgb(0, 0, 255)"
    ])

    Consider

    • If you supply less colors as led lights you have, the rest lights will be cleared
    • If you supply more colors as led lights you have, the superfluous are ignored

    Show lights on hardware

    Send finally your color configuration to the led stripe:

    leds.show()

    Consider: After you have changed your color configuration through any of the above modifying methods, you have to call show() to send the new configuration to the led stripe i.e. to call the callback function you specified at construction.

    Change RGB order

    If your led stripe has another order as red, green, blue (mine have red, blue, green) you can specify on construction another option to define the RGB index:

    var leds = new WS2801({
       count: 32, 
       spiWrite: (data) => { spi.write(data) },
       rgbIndex: [0,2,1]
    })

    In this example I used my configuration: first red, second blue, third green. This has only an impact for the resulting data you will get at the callback function.

    Hint

    On specifying colors you can use any format, which the color library supports with its constructors.

    Examples

    rpi-softspi npm

    Software implementation of SPI to use any pin for the interface on Raspberry Pi instead of using the hardware SPI of the RPi.

    First you have to instantiate the SPI representation and open the communication. In the callback for the WS2801 you have to call the write() method.

    var sleep = require("sleep")
    var SoftSPI = require("rpi-softspi")
    var WS2801 = require("ws2801-connect")
     
    /* we only need clock and mosi for the WS2801 led stripe
     * for all other options of SoftSPI we can use the default
     * begin SPI communication immediately
     */
    var spi = new SoftSPI({
       clock: 5, // GPIO 3 - SCL
       mosi: 3 // GPIO 2 - SDA
    })
    spi.open()
     
    // the led stripe has 32 lights; supply callback as lambda
    var leds = new WS2801({
       count: 32, 
       spiWrite: (data) => { spi.write(data) })
    })
     
    // first make all lights black
    leds.clear().show()
    sleep(1) // wait a second
    // next fill red
    leds.fill("#FF0000").show()
    sleep(1)
    // fill green
    leds.fill(0, 255, 0).show()
    sleep(1)
    // fill blue
    leds.fill([0x00, 0x00, 0xff]).show()
    sleep(1)
    // and black again
    leds.clear().show()
     
    // end SPI communication
    spi.close()

    rpio NPM version

    High performance node.js addon which provides access to the Raspberry Pi GPIO interface including SPI

    First you have to initiate the SPI communication with rpio. In the callback for the WS2801 you have to call the spiWrite() method.

    var rpio = require("rpio")
    var WS2801 = require("ws2801-connect")
     
    // initiate SPI and begin communication
    rpio.spiBegin()
    // max. 25 MHz
    rpio.spiSetClockDivider(10)
    rpio.spiSetDataMode(0)
     
    // the led stripe has 32 lights; supply callback as lambda
    var leds = new WS2801({
       count: 32, 
       spiWrite: (data) => { 
                               let buf = Buffer.from(data)
                               rpio.spiWrite(buf, buf.length)
                            }
    })
     
    // first make all lights black
    leds.clear().show()
    rpio.sleep(1) // wait a second
    // next fill red
    leds.fill("#FF0000").show()
    rpio.sleep(1)
    // fill green
    leds.fill(0, 255, 0).show()
    rpio.sleep(1)
    // fill blue
    leds.fill([0x00, 0x00, 0xff]).show()
    rpio.sleep(1)
    // and black again
    leds.clear().show()
     
    // release SPI
    rpio.spiEnd()

    API

    Check out the documentation for details.

    License

    MIT

    Install

    npm i ws2801-connect

    DownloadsWeekly Downloads

    2

    Version

    1.2.2

    License

    MIT

    Unpacked Size

    1.07 MB

    Total Files

    37

    Last publish

    Collaborators

    • vertumnus