leddriver
v0.0.3
Published
a node.js library to control a SPI led driver (p.e adafruit leddriver) with your Raspberry Pi
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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
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).
I am not responsible for any damages to your hardware. Use this at your own risk.