In this post, I am going to help you build your own relay box for controlling your Christmas lights
. I wanted to share and help you with this project because perhaps it doesn’t make financial sense for you to buy one of these when you don’t need as many channels for your display as the commercial controllers offer.
The good news is that I was able to build this for less than $40. Some of the items I already had available and the rest I did find on Amazon.
Supplies Needed
Listed below are the supplies used in this tutorial.
3 Channel DMX Relay Controller – Buy on Amazon!
Short Extension Cord: Buy on Amazon!
Ammo Box: Buy on Amazon! (Much Cheaper from Harbor Freight or Similar Stores)
Cable Glands: Buy on Amazon!
DMX Cable: Buy on Amazon!
12v Power Supply: Buy on Amazon!
Before getting started I want to note that if are not comfortable with working with electricity then I do recommend reaching out to an electrician or someone that is comfortable with doing these types of tasks.
When working with electricity always be sure to have the power supply disconnected before we start.
Prepping Your Box
For the box, I used a simple ammo box that you can most likely find in a hardware store and you’ll most likely want to go with a plastic one.
You’ll need to install the cable glands so that you can feed your cords through the box. In this tutorial, I only added two but if you want to add more you can do so.
Prepping the Wires
Once you have your box set up and ready it’s time to work on the wires. I just used an extension cord. One for input and one for output. To keep them separate I just used different colors.
In this example, I do use a DMX Cable but if you are just working with standard Christmas lights you can use a network cable instead if that’s what you have around – both will carry the signal just fine!
Connecting the Terminal Block
When working with my DMX Relay Controller I prefer to remove the terminal block to keep the rest of the relay protected while I hook it up.
With this particular relay that I ordered off of Amazon, it did not come with the user manual and it was only available on the product description as seen below.
Please be sure to check this when ordering and make note of the diagram when setting up the terminal block.
The manual will show you what each terminal is and that is very important when setting everything up.
Wiring Everything Up
The first thing to do is to strip your wires for the input and output and be sure to strip enough. Then you’ll want to feed your cords through the cable glands.
Wiring Up the Terminal Block
As I mention in the video as well as earlier in this post when working with electricity always be sure that your Power Supply is off.
Also, if you don’t feel comfortable with working with wires be sure to either have an electric technician or an associate that is comfortable doing these types of projects.
Unplug the terminal block from the relay to help make it easier to wire up everything. First, you want to wire up the outputs to the switched signals. Be sure to refer to your diagram for the relay.
Normally Christmas lights will not have a ground but if you are working with lights that have a ground you do need to make sure you wire it up properly.
When working with your wires be sure that no copper wire is showing because this could fry your relay if the wires cross.
Based on the unit you are working with and the diagram you can start tying off your cables with a wire nut as shown in the video. Once you have everything organized you can start with hooking up the live wires to the terminal block and tightening everything down.
Power Supply
In this tutorial I use a small 12 volt power supply because this is only being used to power the relay, not the actual lights. You can use any 12 volt to 24 volt power supply unit.
If you are not sure which ones are the negative or positive you can use an electrical meter. Just set it on volts and DC, then just make sure you positive is on the positive and the negative is on negative. Just be sure to test this before you turn on your relay.
If you meter reads positive then you are good to go but if it reads negative then you’ll want to switch your wires.
Wiring the DMX
In this case I am using a DMX Cable so I just strip the cable and begin hooking it up to the relay. Be sure to refer to the wiring diagram for your cable to make sure everything is hooked up properly.
With the DMX Cable if anything happens to get hooked up wrong it won’t do any damage. You’ll just need to go back and adjust the wires accordingly.
Setting the Dip Switches
By default, this switch is set on Test Mode. You’ll need to refer to the users manual and set it up as you want. In this tutorial, I set it in DMX mode.
Testing the Box
Once you have everything connected just pull your cables through and close up the box. Just plug everything in and make sure it works properly – not only with test mode, but also with DMX control!