I salvaged a projector that was damaged with a cracked case, and an exploded lamp assembly. It took a while and several bandaids to get all of the broken glass out of it, and then some super glue and a new lamp assembly and it is almost as good as new. Fortunately most of the damage was cosmetic and the internal electronics and optics weren’t damaged.
I wanted to use it to upgrade our virtual matrix/video display setup this year. Our old one used a really-cheap LED-based projector that wasn’t very bright and was definitely not high-definition. I figured I would make something similar to our old enclosure, which was made out of a wood storage box with a clear (plexi) side.
I decided to make it out of 1/2″ “PVC Board” which I found at Menards, and is likely available at most home centers. It’s similar to wood and can be cut and drilled with standard woodworking tools. It’s PVC- so is completely weather and waterproof.
First I cut out a base that’s about 3″ wider on all sides than the projector itself. I drilled a bunch of holes in a grid through it to provide ventilation. This is similar to what I did for the earlier 2021 model.
After making the base, I made a box out of the same material that would overlap it, with about 1/8″ gap all around. This will keep water off the base itself. It’s about 4″ higher than the projector as-well. I just cut the box top about 2″ wider and longer than the bottom, along with side panels to fit under it. I notched the front of the top and sides on a table saw so I could slide a piece of plexi in. I glued them together with plastic/model cement. I pre-drilled and added a couple of long deck screws through each panel joint for a bit of extra support. Once the glue joints were secure, I slid a piece of plexi into the notches in the front and glued and sealed it with clear silicone. I glued some scrap strips inside the box that will rest on the base to hold it up.
Here is what the inside of the initial box looked like after I added the Raspberry Pi (for video playback), fans, and power…
Note that I’m using a USB-to-Serial cable so I can control the projector using the projector plugin for FPP. In this initial version I’m using a small USB adapter to run the RPi and the 5v cooling fans. The fans exhaust out of Bud vents, drawing air in through the holes in the base. Here are the vents I used:
So here is where I say: This didn’t work.
The projector isn’t LED and uses a high-pressure incandescent lamp, which puts out huge amounts of heat. With this setup, the enclosure quickly reached 120℉ and I was afraid the projector would overheat or fail badly. It was also pushing the Raspberry Pi’s CPU to its limits. So, back to the drawing board…
I added a 3rd side vent near the output of the projector’s cooling fan. I also upgraded all three fans to 12v ones with a higher throughput, and added a small 12v PSU for them…
This helped, but the temperature was still hovering around 100℉, which wasn’t ideal. I wasn’t as concerned about the projector failing, but the CPU temperature of the Raspberry Pi was getting alarmingly high, so I made even more changes (Rev. 3)…
I decided to add a vent to the top, and found an RV “pipe cap” at Menards that seemed to fit the bill.
I added it, along with another 12v cooling fan, to the top of the box. I also decided to move the Raspberry Pi controller outside of the box, so there is more room inside for air circulation, and less danger of the Pi overheating. I put it in a small “Apache” waterproof box, along with its own small 5v PSU:
These little Apache cases from Harbor Freight are great for things like this. Unfortunately they are too small for the larger Mean Well PSUs we use, or they would also be perfect for differential receiver and PSU boxes.
The HDMI and serial cable wires just pass out through a hole in the bottom (side) of the Apache case, and enter the main enclosure through a 90-degree PVC electrical conduit fitting (working with what I had in my junk pile) that was just glued to the back. The controller box is just screwed into the back of the enclosure. With this setup, at an outside temperature of 70℉, the internal temperature doesn’t go over 90℉. Of course in the cold winter months it will stay much cooler.
So, this is what the inside looks like now:
Here it is from all sides. I used a small square of the PVC board glued to the bottom to provide a sturdier base for me to connect it to a flange, which was then added to our “Maxi” Tree. Again, this is very similar to what we did before in 2021. It’s not “pretty”, but isn’t really seen at night when the show is running. I might (still) paint it green or red so it’s a bit more “festive” during the daytime.
As a final step- I added some padlock hasps to keep the top secured to the bottom, so the top doesn’t blow off and it is less-likely to “walk away”. Here it is, ready to go, installed in our “Maxi” Tree:
I tested it during a few bad rainstorms and no water got into the enclosure. Being a bit paranoid though, since the top vent is right over the control buttons for the projector, I put a clear adhesive sheet of plastic over the top of the projector. It isn’t blocking any vent holes, but will protect it if any water does come in from the top. I don’t need access to the controls anyway.
The Raspberry Pi runs FPP with the “Projector Control” plugin. It sends commands to power the projector on and off through a USB to Serial adapter. I simply run the provided scripts remotely via my Show Runner FPP to power the projector on and off.
One big thing that is important with projectors like this- they need time to warm up AND cool off. I turn it on 15 minutes before it needs to be used, and make sure to turn it off and let it cool down before killing the show power. This is easy to do in FPP’s scheduler.
If you have a projector that doesn’t have a serial or network interface, you may be able to use this earlier project that I made for the old Vankyo LED projector we used previously. If you don’t use a Vankyo, but can find the appropriate remote codes for your projector, you can modify the code accordingly.