DMX 8 Channel Controller

DMX controller 8 Channel light controller

Please note: that this is provided for informational purposes only and you should be careful when working with any kind of electricity, as it can be dangerous if you are not careful. (This project includes high voltage, please use caution)

A while back I purchased a bunch of SSR’s from eBay and they have been sitting on a shelf, I recently bought a metal electrical box to house them and wire them up. This will have 8 Relays that can switch lights, this will be used as a dedicated controller in my haunted house, specifically the singing pumpkin. The relays are Grouped four to a plug, each plug can handle 13 amps. This will be more then enough to handle the lights that will be connected.

This project will be using the custom DMX controller that is used in the other relay boards I have posted. The solid state relays are activated when 4-6 volts is applied, This will allow me to run them directly from the Microcontroller’s output with out needing A buffer chip on the outputs. This makes it simpler to build the circuit, using only two chips on the board.

The high voltage wiring is pretty straight forward for this project. You connect all of the neutral sides of the outlets to the plug. For the hot side of the outlets, I removed the bridge from the outlets, this will allow me to control each socket independently, Giving me 8 plugs from 4 sockets. Each of the relays will connect to one of the sockets hot terminals, And the 2nd terminal of all eight relays will be connected together and tied to the hot wire from the two plugs. This completes the circuit once you connect the control board you will be able to activate each relay individually turning lights on and off, You can carefully test at this point by applying 5volts to the control side of the relays. This will cause the relay to activate and turn on what every light is connected to the relay.

The wiring for the controller board is straight forward as well, Basically each of the output pins goes directly to the positive side of the SSR’s and the grounds are all tied together and connected to the negative side of the 5 volt power supply, when it receives a DMX signal it turns on the selected output pin, which in turn, activates the relay, turning the lamp on or off.

What you will need:
1. Electrical Box
2. Custom DMX board w/ a 5 volt power supply
3. 2 DMX cables, 3 power cords
4. 8 Solid state relays
5. 4- outlet boxes, outlets, covers
6. screw terminals
7. Tools, Soldering iron, wire cutters, screw drivers, zip ties, drill
8. Wire and assorted nuts and bolts

Case:
The case I ended up using for the project was an all steel electrical junction box. It was about 18 inches by 18 inches. It has pre-cut holes that I used to install the power cables and DMX cables. I had to drill several holes to mount the various electronics and relays, along with the outlet boxes I ended up using.
There are two steps to prep this case. The first is to knock out he plugs in from the precut holes. I installed the power cables and the DMX cables in this holes. The second step is to drill the holes needed to bolt the relays down and to mount the outlet boxes. This also required that I make a route for the power cables to pass thought the first box in to the outlet boxes. I decided to attach the steel outlet boxes directly to the case, to do this I drill holes thought the controller box and the outlet boxes and using two bolt I attached the boxes side by side. There were also holes made to hold status LED’s. I drilled a couple of holes in the side of the case also so I could pass a couple of zip ties thought the case to secure a plastic enclosure inside the case, this was used to house the DMX control board.

Relay:
I used 8 Solid State relays in this build. Each one was rated for switching 120 Volts and had an input voltage of 3-6 Volts. This allowed my to power each relay directly from the micro-controller. I set the relays in the box lining them up in two rows with four relays each. Once this was done I used a pencil to make were I would need to drill the holes to mount the relays. After marking all the holes I removed the relays and drilled the case. Then I was able to set each relay back in place and secure it using two nuts and bolts. To lock the nuts in place preventing issues in the future I put a drop of superglue on the threads once it was tightened. With the relays in place I was ready to move on to the next step.

120 Volt Wiring and Outlets:
For the high voltage side of this controller I decided to split it in to two banks in case I needed to run a higher load on it. To start the wiring I installed two 120 volt power cords in to the box. I also crimped ring terminal ends on to 8 longer pieces of wire and on several short pieces that would be used to make the neutral connections. I connected one side of all the relays together and then the two banks each connect to one neutral wires on the power input cables. Each of the other terminals of the relays have a longer wire attached to them that will feed out to the electrical outlets, since the outlets had the tabs removed two wires will connect to each outlet allowing the two outlets to be controlled independently. The other side of the outlets are then tied together and connected to the hot side of the power cords. This allows me to only need four outlet boxes for control of 8 devices.

A connection was made to one of the power cords to allow a 5 volt power supply to be installed in to box. This was just wired directly to a cord and used to supply power to the controller board.

Controller:
The DMX board used for this project is one that I have used several time. It uses a single parallax SX MCU along with a differential bus transceiver. Since the relays are all 3-6 volts to activate them I was able to connect them directly to the MCU and switch them directly. The board is connected to the DMX in and out cables to pass the signal. It also connects to the 5 volt power supply and status LED’s. They relay connections are very simple, all the negative sides are tied together and to the power supply ground and the positive side each go to one pin on the board.

I Checked all my connections to make sure they were tight, and checked for any possible shorts with a multimeter, finding none, I connected the controller up to power and the computer, and tested all of the outlets, each of them worked perfectly, turning lights on and off when the proper DMX signal was sent. The testing was done using Track-skull, and programming will be done using VSA ultimate.

The controller in this project can be applied to other projects as well, it can be adapted to switch pretty much anything you want. It could be used to make a singing pumpkins or switching any lights on Halloween, or it could be used as part of a light show at Christmas. I am currently remaking this project in to a much small container, I will post that as a separate page when it is complete.

Any questions or comments email: HauntHacker@outlook.com