I got a request to do a step-by-step for this cannon, so hold onto your britches 'cause this one will be in-depth!
Step 1: Go though your recycling bin and hit the thrift store.
I swear, the following picture shows almost all the materials my cannon was made out of, at least structurally. Lights and fancy shiny stuff not pictured, and I never did use the light-up mic.
Nobody drinks soda at my house, so I had to go buy ginger ale bottles, but most people will have these lying around. I used 2.5L bottles rather than the normal 2L ones, for size as well as because I went to the off-brand grocery store and that was all they had. The other stuff came from the local Goodwill. I recommend scoping out the children's toy section (that's where the plastic bicycle pump came from) and the electronics section (that's were the little red crab came from). My advice is to just get whatever looks cool to you: stuff with fiddly bits, things with lots of knobs, interesting shapes, etc.
Step 2: Make the base of the cannon.
Cut the base off both bottles. Cut the top fully off of one and cut a hole in the top of the other. Glue both bottles together to make a super-bottle. You will probably have to clip around the edges to make one bottle fit inside the other.
If you look hard, you can see I also glued a toilet paper roll inside to be the handle. When you are holding the gun, you can grip the "handle" to support the weight of the gun. (Also, it makes you feel cooooool).
The weird red crab thing I glued into the front of the gun is a toy called a "HEXBUG Giant Spider" and you can get them new on Amazon for about $40. Mine was broken and I got it for $2.99 at Goodwill.
I made sure the hole I cut in the top of the bottle was smaller than the base of the Hexbug, so I could glue it in with just the legs pointing out.
|I made the second section taller for variety|
I completely disassembled the child's bicycle pump, and cut up the pump part to create the "clamps" that attach the cannon to the arm.
I attached the clamps with hot glue and I do not recommend this method. They fell off basically immediately and had to be re-glued. I recommend a more industrial glue (E6000, for example). Make sure to properly ventilate if using a cement that's got fumes.
Step 3: Paint!
I spray painted the whole cannon with Krylon for Plastic in blue. Just got it at the local hardware store. Get lots of coats on, because you want it to be mostly opaque. Once there are lights inside, you don't want to see any of the internal structure.
|Threw the whole pack of LEDs inside just for fun|
I also collected all the miscellaneous parts from the bike pump, painted them blue, and glued them on just for fun. You could pretty much use any junky plastic bits and bobs for this--milk caps, pen caps, washers, frosting piping tips, whatever.
Step 4: Light it up!
I don't know a thing about LEDs or electrical engineering, so I bought a battery-powered string of micro-LEDs from Amazon for about $6. (These ones, to be exact).
I cut tiny holes, just big enough for the LEDs, and threaded the light string through. I wrapped it around the gun in each "light section" and then threaded in back in. I used tape to hold them in place, and the battery pack is taped in at the base of the gun. Make sure the battery pack is on the bottom of the gun, so you don't have to fight against gravity.
|Threading the lights through|
I wrapped the last bit of the light string around the top.
|With all the lights attached.|
I just used a dab of hot glue to hold the wires in place, but it was probably not a good idea to mix wiring and heat, so you might want to use something else.
Then it gets a little complicated and also I stopped taking pictures. XD
Step 5: Covering the light sections
Using any kind of flexible plastic (I used a plastic cutting board, but you could use whatever), create a short cone around the top of the gun, surrounding the lights. I used automotive vinyl with a carbon fiber pattern to cover this cone and make it look fancy, but you could just at easily paint it however you wanted.
I covered the light sections with a clear blue plastic (from an old binder divider from my school days), with a layer of blue tissue paper to diffuse the light. I hid the edges by gluing strips of plastic, again wrapped in shiny vinyl, over each yoga mat section. You could also use metallic paint.
|One finised light section.|
I got super fancy and painted some scarab language on the transparent blue plastic. It's just English with the scarab lettering (which I found on Google) and it reads: "Khaji Da, Assignment: Earth."
Once all the lights were in and everything was glued down, I went back with some acrylic paint to do shading, highlights, and touch-ups.
Here you can see it with the lights in, and also with the cone glued on. If you line the inside of the cone with anything blue and reflective, it looks super cool! I also put a layer of blue plastic/tissue paper over the top of the cone, to hide the wiring. Another piece of plastic (cut off the bike pump) was used to cover the gap between the Hexbug and the cone section.
As you can see, there was one LED that wasn't in the designated area, so I glued another little plastic washer over to make it look intentional.
I also cut some zigzags in the plastic that covered the larger light section, to give it that Blue Beetle flair.
And that's it! As long as you are resourceful and creative, every problem is just an opportunity to make something that looks even more awesome.
Total costs: Under $20, and 80% scraps and garbage.