Halloween Ghostbusters Ecto-1 Float

Smigs is back! I still love this time of year and sharing my Halloween process with the few that will read this to the end :) In my quest to continue to be a rockstar dad to my little girl while simultaneously pushing myself to do and learn more, I once again had ambitious plans for Halloween 2025. This year would be the year of Ghostbusters. Admittedly, I did bite off a bit more than I could chew, even with an insane amount of help from my wife, but everything still turned out really well. The original goal was to have an Ecto-1 that I could pull along with us during trick-or-treating, while also showing off a functioning proton pack that both me and my daughter (she was Phoebe--from Afterlife--and I was Venkman) could trade off during the night. After realizing just how bananas both of these builds were, I landed on getting > 50% of the way through on the proton pack, but 100% done on the Ecto-1. Allow me to tell you the rest...

1. My requisite Radio Flyer wagons (that all of my builds fit into)
2. Rough plywood (for the wagon base)
3. Lots of common board (pine) from the local home/hardware store for the overall frame
4. EVA foam to cover everything
5. Rust Oleum Primer+Paint Spray paint
6. Small scale 3D printer files for Ecto-1
7. Ecto-1 roof rack 3D printer files
8. Ecto-1 license plate 3D printer file
9. Pixie lights (to outline the car and really light it up at night)
10. Puck lights (for head/tail lights)
11. 2 police light bars (for the roof rack)
12. 1 flashing red LED (for the roof rack)
13. Mod Podge (to prime the EVA foam prior to spray paint)
14. Miscellaneous coax and stereo cables (for one of the roof rack boxes)
15. Lots of PLA 3D printer filament (from Elegoo and Bambu Lab)
16. Large 1" thick styrofoam sheets (to support the roof rack items)
17. Heavy duty/larger hinges (to hold the two carts together)
18. 2 large AIWA stereo speakers (had these lying around from previous projects) to play music
19. Raspberry Pi 4
20. Digiamp+
21. Little Stay Puft Marshmallow men (from GB Afterlife)
22. Several pieces of plexiglass (for the windshield and trunk door)
23. LED sign that could show text and images (as a nod to GBII's Ecto-1)
24. Painted pool noodles (for the bumpers)
25. Cheap $1.25 grills from the dollar store (to be the front grills of the car)

By mid-Summer we decided we would do Ghostbusters. I wanted to do the proton pack and of course the Ecto-1. Online, a ton of people have built proton packs (there is a pretty sizeable community of people who do this and help each other to do this) but what I hadn't seen were Ecto-1 builds of the variety I was looking to use for inspiration. Ultimately, I found my search results fell into one of two classes:

1. 0.00001% of the population basically made the real Ecto-1. In fact my in-laws were at the beach getting pizza and saw a no-kidding Ecto-1, so they took a pic and sent it to me. It was completely movie accurate with all the bells and whistles. Totally dope.
2. 99.99999% of people did it for their toddlers or small children, so it was pretty lightweight without a ton of detail.

I wanted something that was in the middle. Bigger than something for a toddler that would have enough space to put cool accoutrements and details on (while also supporting cool lighting effects and music), but less than having to build a no-kidding car.

Back in August, my wife and I were mapping out the footprint of the Ecto-1. It was clear that it would have to span two Radio Flyer wagons (like my Hogwarts Express build did last year) and I would be constrained to make sure it could fit into my father-in-law's truck when detached. This led to the engineering drawings above. Full disclosure: I changed the sizes a few times, so for those who are checking my math, it may not totally add up :)

There are two recognizable features to the Ecto-1 IMHO. The first is that the car HAD to have the logo on the front/passenger doors and also the trunk. Secondly, was the roof rack itself. The former was relatively easy to do and we decided to 3D print our way out of the problem. The roof rack, however, was a different beast. My wife and I did a pretty in-depth search online for the roof rack and 2D printed out lots of pics to study. It was an interesting challenge to try and make all those pieces, but for two working parents who could only dedicate 2-3 hours a night on this (after the kiddo went to bed), we had to find another path that would be quicker. Luckily, we found two projects online (which were total gold mines) that contained absolutely amazing 3D printer models of the Ecto-1. THANK YOU to the makers!!

1. Ecto-1 roof rack 3D printer files focused on just the roof rack for a small scale mode
2. Small scale 3D printer files for Ecto-1 had files for the entire car--both exterior AND interior. We used this to add more details around the car

This just saved us and accelerated our progress. Once we knew the dimensions of the Ecto-1, we just scaled up these files appropriately and then had my 3D printers (an Elegoo Neptune 3 Max and Bambu Lab P1S) going ALL the time during September and October.

I laid out my designs and started finding and buying plywood and pine board to use. Because I had two carts, as I was framing everything, I had to make choices which would allow me to disassemble the Ecto-1 into two carts again. Because of this, we decided the "split" would be right after the driver/passenger door. It looked natural and we could temporarily join the plywood bases together for both carts using old, but heavier-duty hinges.

Once the plywood was cut and installed in the carts, I then took my pine board and started framing around the perimeter of the cart and stamping out pieces that would eventually become the doors. There were 6 of these and since I designed them to be all identical, this part flew by,

I then also had to think about the front and back of the car. In the front, I made a somewhat larger area for the headlights and grill because the Ecto-1 had two rows of headlights and I also wanted to fit a decent sized license plate. The hood was simple to make but it retrospect, it shouldn't have been totally horizontal since actual cars don't have a horizontal hood. Finally, I made sure to angle the windshield a little bit to add a touch of realism. For the trunk, we designed and implemented a simple door. We didn't want to have a boxy back end, however, and instead wanted something that looked more realistic. To achieve this, we ended up cutting out several identical curved wooden pieces such that when we put the EVA foam over the top, it would give the curved appearance.

To accommodate the roof rack, the strategy was simple. We built a wooden frame (and could temporarily join the two roof frames from both carts with more heavy-duty hinges) that would allow us to drop a 1" thick sheet of styrofoam on top (made to be removable) and on top of the styrofoam would be the roof rack items. Since these were all 3D printed and distributed over the styrofoam uniformly, we weren't worried about the weight.

I had never worked with EVA foam before. Typically for my builds, I always used either purple interior styrofoam insulation which I then primed and painted or another form of interior insulation that I also primed and painted. There are many foamsmiths (yep, it's a thing) online that walk you through what to do; one example is here. I wanted to try it since it looked fun and was light and easily stored. The downside is it was rather expensive to buy. And I'm not thrilled with how easily the paint job can be marred despite following people's online instructions (at least I think I did).

There was no special magic to installing this. We cut pieces to the appropriate size, cut out holes where necessary, and then chose to screw it into the wooden frame rather than adhere it using contact cement. There were reasons to do this which I won't get into, but it seems to be just fine. After it was installed, I then took my heat gun and applied heat all over the foam to seal it, primed it with a product like Mod Podge (which I think is just a glue/water mixture), and then it's ready for paint. The sealing and priming step was pretty important otherwise the foam would soak up all the paint and the finish would not look great. I ended up using Rust-Oleum primer+paint which I've used for years. I wasn't thrilled with the results, TBH, since scratches on the foam were obvious. I don't know if that was a paint problem or a foam problem, but if I did it over again, I would apply a clear coat layer to hopefully prevent scratching.

As I mentioned in the intro, my 3D printers were going bananas while we were building in the garage. From both of those 3D printer file repos, we were able to use existing designs to help outfit the Ecto-1. I think we scaled and printed all of the roof rack files. They came out incredibly well and we were very happy with them. The only minor issues we had is that some of the larger pieces (such as the fence surrounding everything) had to be broken up into pieces (even on my Neptune 3 Max) and so joining those together created a weak point we couldn't stress too much.

From the full Ecto-1 repo we were able to leverage (hopefully it's exhaustive)

1. Ladder going down the side of the Ecto-1
2. Logos on the doors
3. Tail fin lights
4. Some interior "computer" pieces
5. Blue hose holder
6. Headlights holder
7. 4 wheels
8. Trunk door vent
9. Tail light holders

This particular repo was fantastic and I will be printing a full on miniature version for my office :)

This was the simplest it's been in a long while due to the extent of the Ecto-1 build itself. There were really no moving parts, but lots of lights and music. All the puck lights can be controlled by touch or remote and were AA alkaline battery powered. The police bar and red LED were also battery powered and push-button controlled. The pixie lights required a small power bank, so the only thing I really had to worry about was the music.

To do this, I used my Raspberry Pi 4 with a Digiamp+ and wrote a REST API web interface to serve a browser page which I could control music, car sounds, and the siren from. This was actually something I leveraged from last year's Hogwarts Express build but I wanted to add one small feature which turned into a decent sized code reorg which made it better :) Last year, after a song was over, the logic did not kick off the next song. I wanted to instead just have the next song play.

I tried several times by myself to get this working and I was failing hard :) so I decided to pull in my good friend ChatGPT. With several rounds of back and forth and experimentation with ChatGPT, I landed on a really nice solution.

With this solution I was able to tie my Aiwa speakers into my Digiamp+ and have loud, obnoxious music and sounds parading down the street

The Ecto-1 is rather plain from the roof down. It's a white car (actually based on a 1959 Cadillac Miller-Meteor Futura Duplex which apparently is a combo ambulance and hearse), with some color call outs. The logos were easily printed but the red racing stripes down the side are what make it pretty recognizable as the Ecto-1. My wife and I had a lot of cardboard lying around, so we made a cardboard template for the racing stripes which we would eventually fashion out of EVA foam. We then used that to cut the foam, sealed it, and spray painted it red. We also wanted to secure the cool looking red tail lights to the stripe at the end of the car. To do this we fashioned some styrofoam supports which we cut, glued together, taped with red duct tape, and attached to the foam racing stripe. Given the presence of the styrofoam support, we were able to superglue the red tail lights to it.

Another cool detail, to break up the monotony of having white everywhere, were adding trims and details around the doors. These were fashioned from 5/8" thick pieces of EVA foam that were cut, sealed, and painted too. It just added a little extra realism to the build.

On the driver's side of the Ecto-1 are blue hoses that we definitely wanted to have. Initially unsure how to proceed, my father-in-law said he had old pool hoses in his shed. When he brought them over, they turned out to be the perfect color. So we cut them, and mounted one set of ends into a custom 3D printed box that I designed to secure them to the roof, and the other end went into the back driver's side of the Ecto-1. I simply cut a hole for that and added a surrounding bracket to make it look like it always had been there.

Afterwards, we took our previously printed 3D printed computer pieces (from the full Ecto-1 3D repo) and my proton pack (discussed below), along with stuffies, speakers, etc. and packed it all inside the interior. It was looking pretty cool.

The last cool detail was the LED sign that sat on top passenger side. This was an homage to Ghostbusters II when they had their own LED sign that said something like "We're back" and "For hire". My wife saw something similar on Amazon so we had to grab it. She provisioned it with all the right text and images and then it was ready to go.

I won't spend a ton of time on this because it's not done yet and wasn't a critical part of this year's Halloween design, unfortunately. I used the Tacobelli q-pack model for my build. This had pros and cons.

1. Pros
2. Lots of choices for the design
3. Files support different printer sizes
4. Many people online have done this and share Qs and experiences via Facebook groups etc
5. Cons
6. Instructions are not super clear or complete
7. The repo is not well organized (there's 3-4 versions all mixed in with each other) and it's hard to know which things you should be printing
8. Mounting the pack to the aluminum backing and then mounting that entire assembly to the military ALICE frame (shown in the pic above) is not well-documented

If you have limited time to do this, don't do it. You'll need to start months in advance. It's slow-going. The other complication, which I didn't fully appreciate, is that dealing with the electronics is a whole other beast. Some folks like Wholesome Joe's YouTube series have been amazing at posting their process online, but there just doesn't seem to be a standardized, thorough document for how to do this. Rather, it seems like everyone has to figure it out for themselves every time. Definitely not ideal, and I assume most people are like me, thinking "I just want to get it done to use it vs writing instructions".

So, overall, despite my complaints above, it is super fun to do, but definitely an investment of time. Watching it come together is rewarding, and my goal is to finish it before the end of CY2025.

Despite this build taking a ton of time, and during some of those times feeling like I was riding the struggle bus, we actually ended up finishing two days early! Hooray! Seeing it all come together and roll down the street with crazy, bright, flashing blue lights made my family's eyes sparkle. It was the culmination of two months of effort and we're all very proud of the build we did.

Halloween night was magical. It's the one night of the year I can take a float like this and parade it down the street at obnoxious volume levels at 730pm. My kid was excited, so were my wife and I. People ogled the Ecto-1 and I felt validated lol.

Thanks for reading and see you next year!