raspberry pi as a dmx light controller
When you change the color on the screen, the color on the DMX fixture changes in real time to match.
This can serve as a starting point for a variety of simple lighting items using Raspberry Pi (i. e.
Haunted House, screen lighting control panel, TV backlight, living room DJ settings, etc. ).
A standard $35 Raspberry Pi computer runs a program that generates a screen interface and sends commands to the DMX controller continuously via USB.
The DMX controller then sends the DMX command to the light fixture to change the color.
The hardware is chosen for cost and durability, the software is developed on the platform and is available free of charge in source code and binary format so you can start hacking right away.
What you need is (as pictured ): 1.
Raspberry Pi is a $35 credit card-sized computer with all the basic features of the \"real\" computer, including the free pre-
Built-in Linux operating system (via SD card )
USB for keyboard and mouse, and the most impressive full HDMI video output.
If you\'re new to raspberry pie (or raspi )
We strongly recommend that you wear gloves as soon as possible-
For anyone interested in how computers work, this is a great platform where you can write programs! 2.
USB | raspi, with a built-in DMX controller,
In the I/O connector that does all kinds of cool things, but for this project, we chose to use a USB port as our output interface, because it is simpler and stronger than using breadboards and ribbon cables.
Put things into the DMX (
Digital Lighting control)
Format, we will use Velleman USB to DMX interface.
This can be purchased in kit or pre-order
The constructed form is a very good introduction to controlling DMX devices from computers.
Once you have this controller, you will find it a great tool for any lighting control project you may be doing in the future. 3.
Almost any DMX control light fixture with a red, green or blue channel can work, in fact, if you want to control a whole beam of lights from your raspi, you can put a few chains together.
In this example, we are using the Chauvet LEDSplash 200B spotlight because we found a cheap spotlight online for about $60 and it is very bright,
If you have a DMX dimmer and a standard PAR tank is also good, then it is very important that you have a device that can receive red, green and blue intensity channels. 4. HDMI (
Or NTSC monitor)
Perhaps the best feature of raspi is its HDM interface (
Compared to Arduino video output)
, It provides complete 1920x1080 graphics resolution for any TV screen with HDMI input.
In this example, we used a cheap Vizio monitor, which is in our kitchen and works well for video monitors.
It can be interesting when you use this system as a starting point for a TV backlight project or something like a living room lighting effect because you have a video interface right there1. raspi-
Most of the work on this project is to prepare your raspi for the business.
You can buy raspi from several sources, but our preference comes from the great people of Adafruit industries --
They have been and will continue to be strong supporters of manufacturers everywhere.
You can purchase a raspi: 2 from this link.
Jacked I itself is just a card, so to turn it into a fully functional computer, you need some components that you most likely already have.
It\'s really worth building your raspi into a fully functional computer, because it\'s really a great machine to build any \"smart\" project you think of on the road.
The Raspberri Pi foundation website is a great resource for launching and running raspi.
Please read this page for the information you need to get raspi calculations: 3.
This project uses the stock Raspian \"wheezy\" operating system, which you can download for free from the Raspberry Pi Foundation website.
This page has full details on how to send the OS to the SD card-
Its program is very simple and in less than 20 minutes you can plug the SD card into your raspi and start it and get ready for business. 4. hello raspi!
Once you have the SD card ready and connected the cable, simply plug it into the SD card slot and hit the juice to the raspi.
To your surprise, a computer will appear on the screen.
The stock wheezy issue contains a window manager (LXDE )
You will use login (
Username: pi, password: raspberry)
Start your raspi adventure
Depending on the boot instructions, you can type \"startx\" to run the LXDE window manager.
It takes a few minutes to explore the system.
By the way, if you want to get it into the windows environment every time you insert raspi boot, you can follow the instructions below: 5.
Get the software that wheel\' creates the color wheel interface and talks to the DMX converter and can be downloaded directly to your raspi for free in binary and source formats.
To start, download the free DMXWheel application code from here: dmxwheel source code (zip file)
Launch Midori (
Icon from your desktop)
, And enter this URL.
Click the paper clip to save the file to the desktop when prompted;
This will create an icon marked as DMXWheel. tar.
Gz on your desktop \".
Next, open the terminal window to get the command line interface by selecting the icon in the lower left corner of the toolbar-> Accessories -> LXTerminal.
In the terminal window, type these two commands: this will unpack the DMXWheel application code on the desktop into a folder called \"DMXWheel.
You can open this folder to find the code referenced in the rest of this structure. 6.
Get the extra bits, although it is not necessary to run the program, two additional packages should be installed to make changes and build the source code.
These two packages contain Linux-
Native code for communication with USB (libusb-dev)
, Develop the user interface window (gtk+3. 0)respectively.
These packages are using the name \"apt-get\".
In the terminal, type these commands and follow the program prompt: 7. raspi-
At this point, you should have raspi ready to complete the rest of the project.
The software you will use will be found in the DMXWheel folder on your desktop.
Take a moment to browse this folder and read the README-
It provides valuable information about what the code is, what it does, and how to run it.
We will introduce some basics, but this README file can be used as your local reference document.
There is a lot of cool things to explore on raspi, so when you have time to explore the Raspberry Pi Foundation forum, you can get some great ideas and support from the raspi community.
Now that your raspi is ready, the next step is to connect the light to it.
This is a simple process that basically involves connecting the USB cable from the raspi to the DMX interface, as well as the DMX cable from the interface to the fixture you are using.
Let\'s take a look at the DMX converter first. 1.
USB | DMX | FTW now makes things easier (
Go along this road)
, We are using Velleman\'s VM116 USB to control the DMX interface.
This box performs the simple function of converting the serial data sent via USB to the DMX signal sent to the DMX unit.
The unit has two models depending on whether you buy it as a kit (K8062 )or assembled (VM116 ).
The kit is not particularly difficult to manufacture and the price difference is about $20: as can be seen from the picture, the device needs USB (D )
Input, this is the most common USB cable connection.
Chances are you already have a D to flat USB connector located somewhere.
The DMX out connector is a standard XLR connector commonly used for microphones and other balanced audio functions;
These cables are good, so don\'t bother buying DMX specific cables unless you feel you need to spend more money. 2. hub up?
Yes, one thing you may have observed is that raspi has two USB ports, both of which are currently used by your keyboard and mouse.
For this reason, we recommend that you look for cheap USB hubs;
You may already have one sitting somewhere, or you may find a mouse set on a keyboard (i. e. internal hub).
We got an electric hub at Office Max for $10, so with some shopping you\'ll find that working with raspi makes life easier.
Another reason to get the power hub is that it removes the power load from the USB connection on the raspi, thus reducing the power load on the power supply on the raspi.
Of course, you can run this project without a hub (
Disconnect the keyboard after starting the program)
, But developing an application in any important way can be cumbersome. 3.
Put it all together to complete the connection of the raspi to light, connect the USB cable from the converter to the raspi, and from the converter to the DMX light unit.
At this point, you should have the cable to connect the mouse, keyboard, display, DMX converter and lights together and be ready to start the program.
The last thing in this project is to start the project and have some fun! 1.
The source code contained in the DMXWheel release contains the two programs needed to run the project.
The way the code works is that there is a program running as a background process that reads the shared memory location that contains the state of the DMX channel.
The second program runs directly at the front desk and opens the color editor to change the strength value in the shared memory segment.
This division of labor allows the raspi to maintain a constant line of communication, turn on the DMX controller, and update at a fixed time interval, regardless of which application manipulates shared memory.
The two programs communicate with each other using a C library containing simple functions that set up DMX channel data so that shared memory operations are transparent.
These programs are published in binary format and do not need to be recompiled, but you can do this if you want to make changes to the code or write your own program using a DMX controller.
The software you downloaded has the following structure: the first step to getting started is to start the DMX controller interface program running in the background.
In Linux, this is the daemon.
This program only needs to be started once each time the system is started.
To start this program, Type: 3.
The second step in showing the color to get things going is to start the DMXWheel program.
This program creates a window with familiar color wheels that you can edit with your mouse.
As you can see in this photo, there is an outer ring with a grab line, you can drag around to change the tone, a circle inside the center triangle that allows you to adjust the saturation and brightness.
When you move this control, the color of the light changes accordingly.
You can start the program using the following command (
And exit the program by closing the window)
Congrats you did a good job.
After trying the color wheel, all sorts of outrageous ideas are likely to pop into your mind.
With the hardware you have, you have all the resources you need to use your DMX compatible device in your raspi app.
It\'s time to start making!
You may find something useful when developing your own application: 1.
Look at DMXWheel.
The program is very simple but shows you two important things.
First, it shows you how to set the DMX channel using the DMX library function call.
You can easily change the code to support different channels, additional channels, etc.
Second, it shows you how to open the GTK window on the screen.
Search on GTK and you will find a complete function library that can be used in-
You don\'t need to see the screen interface from scratch. 2. check out dmxd.
C The program is the other side of the shared memory coin for serial command communication for the DMX controller.
This code describes the packet format for sending data and provides you with details on how the DMX controller explains the data. 3.
See how cool other DMX devices are-
This simple app only writes three channels for the light unit that represent the available 512 in red, green and blue, but you can also support motors, lasers, strophers, and a variety of smart devices, just adjust the code a little. 4.
Take a look at the raspi we \'ve touched on this amazing device, but if you go around, you\'ll find the board can be impressive
3D graphics, stereo audio, Universal I/O, etc.
It\'s just released so keep an eye on how it\'s going and more features and apps can make your project live.