Hobbyist Forums banner

1 - 12 of 12 Posts

·
Registered
Joined
·
2,680 Posts
Discussion Starter #1
Continuing my minor obsession with "The Invaders" of late.

This is a very simple 3D printed kit I got off of eBay, only 3 parts, buy the resolution is very low, large print lines.





As you can see, it's very shallow.

I used XTC-3D to smooth out the surface.



And a coat of primmer.



This seems to have worked well.
 

·
Registered
Joined
·
2,680 Posts
Discussion Starter #2
As near as I can figure out the body was painted a dark silver/grey. I chose light gun metal.
The center disk is black.







So now I have a decision to make. Do I close everything up and make it a static prop?

Or do I try and light it?

The major issue is the lack of space. The inside only has 1/8 inch of depth.

I did find this:



It fits well:



But there is no room for a battery.

I don't want power wires coming off of it, so if I cant find a very thin battery I'll go with a static prop.
 

·
Registered
Joined
·
2,680 Posts
Discussion Starter #4
Thanks, but everyone I've found is too thick.
The LED disc uses 12V, which kind of limits things.
 

·
Registered
Joined
·
1,038 Posts
How are your soldering skills? You could cut the traces on the PC board to isolate the LEDs into smaller groups and solder wires to put those groups in parallel. If using a 3V battery you would use 2 LEDs in series with 5 pairs in parallel.

But those LEDs would kill a wafer battery pretty fast and those are not cheap, can you cut out 2 slots deep enough for AAAs?
 

·
Registered
Joined
·
2,680 Posts
Discussion Starter #6
Good idea Marty, thanks very much for the suggestion.

Unfortunately the the LED board is sealed on the bottom.



In that photo I put a AAA battery inside the disk. It's way too wide.



As you can see the whole housing is just about the same thickness as the battery.

For this to work I'll need some unltra thin battery.

Has anyone heard from teslabe lately? He always seems to find interesting ways to light/motorize very small things.
 

·
Registered
Joined
·
1,038 Posts
I can see the traces on the top of the board under the solder mask, so it would be easy to cut them. Looks like that is an aluminum sheet on the back of that LED board, probably a heat sink, and I just noticed it says 5W on it. So those are half watt LEDs, those would kill any small battery in no time.

Trying to think what would fit in the center hole, a couple of watch batteries would fit, along with some really small LEDs glued to the wall of the hole. Best it would do is give a little glow to the transparent 3D printed disk.

The old school prop department way of doing it is to paint the part you want to glow with highly reflective paint, then shine a light on it. More modern stuff is microprismatic tape. You could tear apart a white driveway reflector disk and drill it out to look like the 3D printed disk. Or glow in the dark paint on the back side of the disk.
 

·
Registered
Joined
·
5,754 Posts
I love this and intend to discuss it later, but for now here's an old school idea via the forgotten past and a friend of mine.

How about taking apart a 9 volt battery and using the cells contained within? I recall various fan made items that used these. Mind, when the power died you had to go back to the maker to put new cells in...

What I recall is that each cell was like a smaller than AAA battery, all connected. I think they worked out to 3v each.

Do they make 'green' (rechargeable) 9v batteries? if so maybe the cells could be used, and just need a micro USB port.
 

·
Registered
Joined
·
2,680 Posts
Discussion Starter #9
Thanks for the input!

Marty, you obviously know much more than I do about this stuff, it makes sense that the 5W means .5W and would kill a small battery very fast.
I have some 3mm LEDs on the way. I could probably fit 3 CR2032s inside for power. That might be the way to go.

I also like your idea of a reflector. This is what I did when I made my season 1 death disk. The "lights" are small crystals.



I can easily do that for this prop.

Steve H,

Wow! taking apart a 9V! I've never heard of that, ambitious and a very interesting idea.
 

·
Registered
Joined
·
1,038 Posts
Yes, some 9V batteries have 6 tiny cells in series that look like small AAAs, each one the same voltage as a single AAA/AA/C/D (1.5V) just smaller capacity.

But some 9Vs have a stack of flat cells in them that can not be separated into working cells.

I don't know if it's an alkaline/rechargeable/drycell thing or completely random, but I'm sure there are plenty of videos out there that have people tearing apart 9V batts.
 

·
Super Moderator
Joined
·
24,372 Posts
I was wonder how they powered the original prop back on the show? I was thinking an external power source held in the hand behind the disk. With todays technology a magnetic/electrical charger or power transfer would work the same way maybe?
 

·
Registered
Joined
·
5,754 Posts
I was wonder how they powered the original prop back on the show? I was thinking an external power source held in the hand behind the disk. With todays technology a magnetic/electrical charger or power transfer would work the same way maybe?
I would guess the prop was lit with pea bulbs, with a cord running up the sleeve to an off screen power source. If it flickered or pulsed it was likely manually controlled via a rheostat. I haven't seen hardly any of the show (I had my 'misfortune' before I pulled the trigger on buying the DVDs. and of course can't afford such luxuries now) so I don't know how it was used or shown in the episodes. If we only see it lit in close up then I would assume it was only shot by a second unit guy with some assistant doing the holding/operating.

Might it be safe to assume this was developed to reduce the need for rotoscoping death beams? :)
 
1 - 12 of 12 Posts
Top