Using an RGB full-color LED DMD

Related Config File Sections
displays:

MPF supports RGB full-color LED DMDs. There are several hardware options you can use for this:

This guide shows you how to configure MPF to use one of these displays.

By the way, these RGB LED DMDs have been called “real” Color DMDs in the forums since the displays are arrays of RGB LEDs rather than an LCD monitor running a display that is made to look like a DMD. Many people like these better than LCD-based displays because they’re brighter and more vibrant, and the blacks are actually black since the LEDs are off versus LCD displays which have blacks are are actually dark gray.

../../_images/display_rgb_dmd.jpg

We will also show you how to create an on-screen popup window which will show the contents of the DMD, like this (with a blank DMD):

../../_images/on_screen_basic_dmd_window.png

If you want to use a physical RGB DMD without the on-screen equivalent, we’ll show you how to do that at the end of this guide.

If you want to only have an on-screen DMD without the physical one, like if you want to replace the DMD with an LCD screen but still have it look like a color DMD, then read this guide instead.

The final version of the relevant sections of your machine config for a physical RGB DMD with an on screen window too will look like this:

1. Shout-out to Eli Curtz!

It’s likely that no one would be using RGB LED DMDs if it wasn’t for the efforts of Eli Curtz.

Eli first posted about these types of panels in the P-ROC forum in 2014. At that time we could only find panels with 3mm spacing between pixels which was a bit larger than traditional pinball DMDs, but that’s what kicked off the conversation about, “Whoa, maybe we could use these for ‘real’ color DMDs some day.” Then in September 2015, Eli posted again telling us that we could now get panels with 2.5mm spacing which is the perfect size we need. Eli also showed us how to connect them and what software we needed to make everything work. So really everything here is because of Eli. All we did is take everything he showed us and write it down. (Well, that and we also created the interface for MPF, but that was the easy part.) So thanks Eli!

2. Add your displays to your MPF config

Next, add the DMD display to your list of displays in your machine-wide config file:

displays:
  window:
    width: 600
    height: 200
  dmd:
    width: 128
    height: 32
    default: true

The example above contains two displays. The first is named “window” and has a size of 600x200. This will be the display that shows up on the computer screen. (Again, if you just want the DMD without an on-screen window, we’ll show you how to do that later, but for now it’s probably easiest to create a screen window so you can see what’s happening with the display if you’re working on your game without a physical machine attached.)

The second display, which we’re calling “dmd”, will be the display that provides the content for the physical RGB DMD. This display is 128x32, which is the pixel size of the DMD. If you have a different size DMD, enter the size (in pixels) here.

Notice that we set default: true for the DMD display. This is because as we’re creating display content in our game, we want it (by default) to show up in the DMD (since that will be the primary display in our game).

3. Add your window configuration

The window: section of the machine-wide config holds the settings for the on-screen display window. If you don’t have this section, add it now.

You can make the width and height anything you want. In this case we’re just configuring it to be 600x200 with a window title of “Mission Pinball Framework”.

window:
  width: 600
  height: 200
  title: Mission Pinball Framework

Check out Step 2. of the LCD guide for more details on this window section, and be sure to check out all the window options in the window: section of the config file reference.

Notice that in this case, we did not add the source_display: window setting to this section. That’s because we have a logical display called “window”, and when you have that, the on-screen window will automatically use that display as its source.

4. Configure a window slide to show the on screen DMD

Now we have a working on-screen window and a working physical RGB DMD. But if you run mpf both now, your on screen window will be blank because we haven’t built any slides to show up.

So in this step, we’re going to build a slide for the on-screen window that will be shown when MPF starts. We’ll add some widgets to that slide to make it look like the screen shot at the beginning of this guide.

First, create a slides: section in your machine config (if you don’t have one already), and then create an entry for the slide that we want to show. In this case, we’ve decided to name that slide “window_slide_1”. (Of course you can call this slide whatever you want.)

slides:
  window_slide_1:

Next we have to add some widgets to that slide. (Refer to the documentation on widgets if you’re not familiar with widgets yet.)

The first widget will be a Color DMD widget which is a widget which renders a logical display onto a slide in a way that makes it look like a DMD:

- type: color_dmd
  width: 512
  height: 128

Again, there are lots of options here. Note that we’re adding a height: and width: of 512x128. This is the on-screen pixel size of the DMD as it will be drawn in the window. In this case we chose an even multiple of the source display for the DMD (which is 128x32), meaning that each pixel of the original DMD will be rendered on screen as 4 pixels by 4 pixels. This is big enough to get the circular “dot look” filter to look good, and being an even multiple means that we won’t have any weird moire patterns.

There are other options listed in the Color DMD widget documentation to control settings like how big the circles are versus the space in between them, the ability to not have the “dot” filter, and the ability to set the “glow” radius of each dot, color tint, limiting the color palette, etc.

Note that in this case, we did not have to add the source_display: option because we have a display called “dmd” which will automatically be used as the source for the color DMD widget.

Next, we also added two more widgets to this slide—a text widget with the title of the machine, and a gray rectangle that’s slightly larger than the DMD to give it a nice border.

- type: text
  text: MISSION PINBALL FRAMEWORK
  anchor_y: top
  y: top-3
  font_size: 30
  color: white
- type: rectangle
  width: 514
  height: 130
  color: 444444

5. Configure the slide to show when MPF starts

Now we have a nice slide with the virtual DMD on it, but if you run MPF, you still won’t see it because we didn’t tell MPF to show that slide in the window. So that’s what we’re doing here:

slide_player:
  init_done:
    window_slide_1:
      target: window

If you don’t have a slide_player: entry in your machine-wide config, go ahead and add it now. Then create an entry for the init_done event. This is the event that the media controller posts when it’s ready to be used, so it’s a good event for our use case.

Then under that event, create an entry to show the slide you just created in the previous step. Notice that we also have to add the target: window entry to tell the slide player that we want this slide to show on the “window” target. We need to do this because the default display (from Step 2) is the DMD, so if we don’t specify a target, this slide will show on the default, which would be the DMD, instead of being shown on the window. (In this case, we would show a slide on the DMD which contains a DMD widget whose source is the DMD, and we’d probably open up some kind of wormhole and destroy the universe. So don’t do that.)

And this point, you’re all set! Of course there’s no content on the DMD yet because we haven’t set up any slide_player entries to add content to it, but that’s something you can do by following the tutorial or looking at the guides for the slides and widgets here.

6. What if you don’t want the on-screen window?

There might be some scenarios where you just want the physical DMD with no on-screen DMD. (For example, maybe you’re using a low-power single board computer and you don’t have enough horsepower to run a graphical environment.)

This is fine. To do it, just remove the window-related components from the config.

In this case, you wouldn’t need the default: true entry for the dmd in the displays: section because you only have one display, so it will automatically be the default.

7. Configure your RGB DMD Hardware

At this point you have two displays configured, and you have default content showing up in both of them. The final step is to add the configuration for your physical RGB DMD so that MPF can talk to your hardware.

The exact steps to do that vary depending on which DMD hardware platform you’ve chosen, so click on the one you have from the list below and follow the final instructions there to get everything set up.