now I just need to work out the battery requirements...
bunch of different options:
1) each module gets it's own battery located in the chamber, pointer style, with a common switch
2) single large battery/array lots of wire and a common switch (possible resistance issues?)
If your lasers have separate drivers (and they should!) you can use one big battery at the needed voltage and power them all. Just make sure that the battery can provide enough amperage to supply all the lasers.
Note that this is for single types of lasers. If you want to combine colors, you should have separate batteries just so you can ensure you have the right voltage. It may not matter if you use Dr. Lava's Flexdrive, however, since they can accept virtually any input voltage for any output voltage. That might be the way to go to use a single battery source.
3) cylinder rotates with trigger pull, laser activated by contact pad/brush location at top dead center, power needs to be strong enough to achieve full power with split second contact and over coming the resistance of the contact/brush set up
If you're going for a gatling-gun type look, are you really going to need multiple lasers since they're supposed to look like they're coming out of the same single barrel? Instead, you could just use one powerful laser in the output barrel, and turn on/off the laser to make it appear like it's shooting individual pulses from multiple chambers, while rotating the barrel. This would eliminate the mechanical aspect of having a laser in the barrel, making potentially high-powered sparks, etc.
For more colors, check out these $100
10mW blue lasers. They have TTL modulation, so you can turn them on and off as needed. It won't help you if you still want to spin the barrel with the lasers, but it's still a nice bright blue.
You can likewise get a TTL-modulated
green for $50.
For red, you'll be limited by the brightness the beams appear to have. Something to try is to mix them with a bit of green to get a more yellowish (center) beam effect. It'll give the beam a brighter core in conjunction with the reddish halo around it. A lower-powered green core with two or three reds around it would make a nice fat, bright beam.
4) remote power pack connected by quick disconnect cable
For portability, get some LiPo batteries that can source enough current (
like this). You can also use some NiMH battery packs, the kinds used for RC cars.
Finally, you might just want to buy some
battery holders and use some 18650 LiPo batteries since they're pretty high capacity, useful voltage (3.7-4.2V), and can source quite a bit of juice.
4) 1 module and beam splitter mirror array..... not really a great idea for a hand held prop that needs to be able to take some bumps and knocks
It's hard to get those aligned precisely, and when you do, you need something extremely rigid. Check out Morgan's mini
beam combiner. Maybe look at what If you do rig something up, I'm sure you could sell them here too.