Using Node.js and a Raspberry Pi to monitor Streaming ACN network for DMX changes and trigger actions

Awhile back, I wrote about the Shade Controller I created using Node.js and a USB relay running on a Raspberry Pi Zero. It works great. We can raise and lower the shade from anywhere on the network. However, I’ve always wanted a way to control this a little more automatically. The lighting volunteer is typically the person who operates the remote for the shade, so I really wanted a way to automate that part of the process for them so the shade can raise and lower exactly when we want it to, without them having to use an extra tool or device.

As I was working on some networking changes to one of our lighting consoles (we use Jands L5 consoles running Chroma-Q’s Vista 3), I had an idea… What if we could monitor the Streaming ACN lighting network for data changes just like any lighting node, and use that to trigger an action?

If you’ve not heard of Streaming ACN (sometimes called sACN or its official name E 1.31), it is an ethernet based protocol for sending DMX address and value information from a lighting console to receiver nodes which then relay the DMX information to lighting fixtures. It uses multicast traffic to send the information so it is very fast and efficient. At my church, we have several DMX universes of lighting information going over the network for each auditorium, controlling all of the light fixtures.

Luckily for me, a base protocol module for E 1.31 was already available for Node.js. So, using that module, I sat down and prototyped a solution and had something working in just a couple of hours. I’m calling my software sACN Translator. I’ve deployed it to a Raspberry Pi for production. It supports a simple REST API to allow you to control which universes it should listen to, as well as the fixtures to run triggers for. I also created a simple web interface which utilizes this API.

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Here is the simple web interface which interacts with the REST API.

Here is how I set it up on our system to trigger the shade controller. I started by adding two fixtures to the L5 console on Universe 1 (where I happened to have some spare room in my DMX addresses). I called these fixtures “Shades Up” and “Shades Down”, with DMX Addresses 511 and 512.

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Here are the two “fixtures” on the layout, with notes attached.
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I labeled the fixtures as generic “utility” fixtures with 1 DMX address each.

Then, I added entries in sACN Translator to monitor Universe 1 on the network and look for value changes to fixture addresses 511 and 512. I set it to run an HTTP trigger any time the values reaches 255 (100%). So, when I put the Shades Down fixture at 100% on the lighting console, the software sees that value, looks for a match in its list of fixtures, and then runs the corresponding HTTP request on the Raspberry Pi Zero connected to the USB relay to trigger the action which lowers the shade.

Here is a video of it in action:

Pretty cool! I decided to use separate fixture addresses for each trigger action, but I didn’t have to. I could have just one fixture and watch for two separate lighting values.

So now, all the operator has to do is run the cues like normal, and the programming will do the rest! I’ve made this software available for free on my Github repository. Let me know how it works for you!

Server-based countdown clocks with multiple client viewers using Node.js and a Raspberry Pi

A few months back, I shared about the client-side countdown clock script that I created for our team to use. It worked pretty well for its purposes, using Dropbox as the platform to share and update data between the computer creating the clocks and the computer viewing the clocks. The initial goal was to create something that required no backend server and would be easy to run on any computer.

It served us well but we quickly outgrew it with the desire to be able to publish clocks in realtime, not simply relying on the viewer client to refresh itself every 15 seconds to look for new data. So, I created a server based solution using Node.js.

I decided I wanted to run this project on a Raspberry Pi 3 B+, so I picked up this kit on Amazon. I wanted an easy way to spin up a web server that wasn’t tied to any production machine, and this does a great job.

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Here is the Raspberry Pi 3 B+, neatly installed in one of the video racks. I’m using the HDMI output and converting it to SDI to go into our video system.

Dubbed TimeKeeper, this project runs an Express web server within Node and has a REST API, which allows the user to poll for existing data as well as create new entries. As new entries are added, they are sent out to all connected clients in real time using the socket.io library.

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Here is a screenshot of a web browser client. This is actually running on the same Raspberry Pi that is hosting the Node.js server, with Chromium in kiosk mode.

Rooms:
Rooms allow you to control and specify which timers appear. This is helpful if you are running clocks in multiple venues or instances, and only want certain timers to appear on certain viewer screens.

Timers:
Timers are the objects that TimeKeeper will count down to, based on the viewer’s current local system time.

Messages:
Messages can be sent and displayed on viewer clients.

After implementing the API, I created a Dashboard custom panel to interact with the server. This serves as the primary interface for our volunteers. Because the panel fetches new data from the server on a recurring schedule, multiple computers can have the panel open and all stay in sync about what timer and message objects are currently being displayed.

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Screenshot of the custom panel in Dashboard.

We’ve been using this software for a few months now and it’s working great! I intended to write about it sooner, but with a busy work and family life, finding time to write for this blog can be a challenge!

The next version will support trigger actions when clocks hit a specified time or run out. I also plan to integrate with other clock systems to show time left on video playbacks, Planning Center Online, etc., when I have the time!

If this is useful or helpful to you, I’ve made it available on my Github repository.