node-enttec-open-dmx-usb 🔌

A Node.js library for interacting with the Enttec Open DMX USB interface

As it uses serialport under the hood, it should also work in these environments.

Install

The minimum required Node.js version is v18.0.0.

yarn add enttec-open-dmx-usb
# or
npm install enttec-open-dmx-usb

Usage

View documentation on jsdocs.io

import { EnttecOpenDMXUSBDevice as DMXDevice } from "enttec-open-dmx-usb"

(async () => {
  const device = new DMXDevice(await DMXDevice.getFirstAvailableDevice())

  device.setChannels({
    1: 0xFF,
    2: 0x44
  })

  // same as
  device.setChannels([0xFF, 0x44])

  // same as
  device.setChannels(Buffer.from([0xFF, 0x44]))
})()

What to do when this doesn’t work

TLDR: Because setTimeout is imprecise, install easy-sleep and pass the usleep function provided by it as the third parameter to the constructor of EnttecOpenDMXUSBDevice. See the example below.

From the Node.js documentation regarding setTimeout:

Node.js makes no guarantees about the exact timing of when callbacks will fire, nor of their ordering. The callback will be called as close as possible to the time specified.

Because of this and the passive nature of the Enttec Open DMX USB interface, sometimes the timing requirements of the DMX specification are not met. Using a library such as easy-sleep which allows sleeping (i. e. blocking the event loop) for a precise amount of microseconds is a possible workaround.

You may pass a function sleeping for n microseconds as the third parameter to the constructor of EnttecOpenDMXUSBDevice.

For example, using easy-sleep:

import { EnttecOpenDMXUSBDevice as DMXDevice } from "enttec-open-dmx-usb"
import easySleep from "easy-sleep"

new DMXDevice(await DMXDevice.getFirstAvailableDevice(), true, easySleep.Thread.usleep)

Events

ready - startSending may be called.

error - An error occurred. error events from serialport are passed through.