So some of you may have seen how the north-eastern boys identifed the bargraph used on the throwers for the first Ghostbusters movie. Unfortunately at over $1k per bargraph, it’s not exactly something most people can afford or are willing to spend that kind of money on. But since they actually had one in hand we finally got some detailed shots of it so I took it upon myself to see if I could make a reasonably convincing replica on the cheap.
I started by thinking about the bargraph as layers, and then traced out those layers in Illustrator to be laser cut out of acrylic.
I knew there were going to be black opaque layers and then transparent layers that would either be clear or have a pattern etched into them, so I placed the transparent layers aside and used the opaque layers to build what is essentially the housing, which was then molded and cast.
The housing has a very thin frame around the outside edge, a smaller frame underneath, silver “teeth” that must have something to do with the leads on the real bargraph, and since the correct 30-segments are hard to come by I went ahead and added a layer that divided out 30 segments.
The first layer of the transparent acrylics. In the future I will have the pattern from the middle piece engraved onto the thicker acrylic to the right.
Then I’ve added the second layer of acrylic, the face cover. The fit is a little tight so I had to sand the edges of the acrylic, I will have them cut slightly smaller in the future so the edges will be clean.
I’ll try to get a video later. Using a 15-segment bargraph isn’t perfect, it looks okay, but I would imagine the animation would look much smoother using one of the 40-segment bargraphs.
TC, your skill just continues to floor me, excellent work on the pieces… you’ve brought it as close to perfection as you can get without having the real thing.
Consider myself another interested party if you decided to mass produce these.
This looks amazing! I have been thinking about a replica like this for quite a while now and the ways it could be put together, but you were able to come up with a working idea it and make it a reality. I am very impressed with this.
As for the way the 15-segment lights look… it seems like the light is bleeding a lot, creating a bit of undesirable glowing effect. I wonder if there is a way to better isolate the individual LEDs so that light from a lit LED does not bleed into the portion of the bargraph that should be unlit.
When I look at the LEDs without the bargraph replica in place, they are bleeding into each other. So I would imagine it could be solved by placing a little bit of black electrical tape between each LED then making sure the LEDs are bumped right up against the back of the replica. I’m just holding these all together by hand, nothing fancy.
I’m amazed by this, I hope they do go on sale because it will add so much to alot of builds and I suspect the majority of people won’t be able to afford or be willing to splash out on the original item.
I am a sparky, so the mechanical building is all black magic to me. Would you mind giving details somewhere about how you go about getting something “molded and cast”? Maybe a separate design/build thread or pointer to similar info would be greatly appreciated!
Have you thought of using lenticular material instead of patterned acrylic?
In a cover for my bargraph I am using 75 lpi, 18 mil PET and it gives a look very close to the striations that are visible in the actual bargraph photos.
