Best device(s) for this cosplay

Amethyst said:

-An intake and exhaust fan in the helmet, like RasPi mini fans (5v), for temperature and breathing. I plan to fit these in the "ears" of the helmet that the hoses attach to.

Depending on budget and space available, I would have a dedicated microcontroller for fan control and combine that with at least a temperature sensor, could be combined with a humidity sensor and then alter a 'fan curve' for how fast the fans rotate depending on temperature and humidity, with a manual override for "just whack it up to full speed please".

With the use of MOSFETs you can control fans that are 12v, though it then depends on your power supply, but that would allow you to use fans that were either larger, or more powerful to move the air as needed, while being controlled by a lower voltage microcontroller, say from an Arduino or similar.

You may also find that you only need an intake , or that you need two exhaust, with no intake, or only one intake, depending on how you want to setup the air pressure.

Amethyst said:

-Some kind of screen in the helmet that can tell me information from the board. Looking at battery level, temperature, and possibly proximity sensor information.

A small OLED or LCD screen can possibly do this for you, or if you find a small epaper/eink display then it only has to update and refresh the screen every few seconds or minutes rather than using power for the whole screen constantly. Again this could be a microcontroller or something 'beefier' with an operating system like a Raspberry Pi (such as a Zero or Zero W) but then that introduces battery drain and failure points and waiting for it to boot.

Amethyst said:

Arm Blaster:

-Ice Beam using compressed air, unless there's a good electronic alternative? 

-Ping pong or Airsoft pellets. Which would be cheaper to build? Doesn't need to be high pressure, of course. 

-Fireballs by flash paper and cotton with a glow plug. Suggestions on safest way to control it? Not sure I want a 12v stepper in my arm cannon, not sure if a lower voltage would do the job?

Hm, well if you're wanting more than a dummy 'push button, activate motor' or 'I'm reusing a nerf gun' then you're probably looking at using steppers and a microcontroller, because wouldn't it be cool to have it synchronised with sound and light actions too? It's probably easier to look at this from a 'what would it take to do each type of thing, does something already exist? does it need to be more complicated?' than trying to build it from the ground up off the bat.

Compressed air is going to have a limit, but perhaps there's something like the airzooka that would work in a smaller confinement?

Ping pong balls are relatively cheap, light. An alternative would be the nerf balls that blasters use, or a nerf blaster itself. Maybe the dog toy version.

I'd avoid fire. If only because of health and safety paperwork at cosplay conventions. 

I'm going to read this as I respond, because it's easier for me to sort that way than try to remember. ^_^;
That said, sorry if I ask or answer something you elaborate later. Also, I'm bad at the quote thing.

"...then alter a 'fan curve' for how fast the fans rotate depending on temperature and humidity, with a manual override for "just whack it up to full speed please"." 
Is there honestly a reason a complicate it using this? Just to save battery? So far, I'm planning to just connect the helmet to the main battery on my back.

"With the use of MOSFETs you can control fans that are 12v ... would allow you to use fans that were either larger, or more powerful to move the air as needed, while being controlled by a lower voltage microcontroller, say from an Arduino or similar.

I've never got to make anything with MOSFETS, AFAIK. With a fan blowing directly on me, I'm concerned too strong may be too much sensory. I'm also considering to run a hydration line from one of the shoulder pieces, like a hydration backpack. This would likely go down the tube from the right side of my mask, while air come in my left side, eg through the left hose. 

"You may also find that you only need an intake , or that you need two exhaust, with no intake, or only one intake, depending on how you want to setup the air pressure.'
Would you like to expand upon this? I'm still considering how I'll want the exhaust to work, though I'm looking at intake being through the right "ear" bubble.

"A small OLED or LCD screen can possibly do this for you"

My question here is how would I make it work in this confined space? Ideas? It's one of the two things that's been holding up my project. Specific models in mind? I have been wondering if there's a small LED projector that works by reflection, but that may be worth it's own post if not answered here.

"or if you find a small epaper/eink display then it only has to update and refresh the screen every few seconds or minutes rather than using power for the whole screen constantly"
Same as above, but this simplicity seems closer to what I wanted , except quick alerts if I included a form of sensor to detect behind me. Can this be updated more quickly with more power? Eg I trigger it to redraw the screen if something is 5ft behind me? That sounds AMAZING!

"this could be a microcontroller or something 'beefier' with an operating system like a Raspberry Pi (such as a Zero or Zero W) but then that introduces battery drain and failure points and waiting for it to boot."

I'm perfectly fine with a "Boot Sequence". Hell, I can make that work amazingly!
Imagine it's booting up, and plays the NES "Secret Area" music? Then when completed, it plays the "Same Start" music?! It making that music could also tell me my battery is dying, others here it as I seem to rush off (not knowing to change my battery).

"you're wanting more than a dummy 'push button, activate motor' or 'I'm reusing a nerf gun' then you're probably looking at using steppers and a microcontroller, because wouldn't it be cool to have it synchronised with sound and light actions too?"
I've planned it to be a mix of parts in there, but I NEVER considered having it change the lights! Even if I do repurpose a nerf gun or something, I can have a button to push with it to do so! Thanks!


"It's probably easier to look at this from a 'what would it take to do each type of thing, does something already exist?" 
That's why I'm asking. I know other ways to do most of this, but did not keep up with tech over 5 years.

"Compressed air is going to have a limit"
There's a trick you can do with compressed air that it shoots ice crystals. I just try to leave it vague because it can be dangerous if not handled correctly.

"Ping pong balls are relatively cheap, light. An alternative would be the nerf balls that blasters use, or a nerf blaster itself. Maybe the dog toy version."
Thanks! Will look into. Like I said, can still connect a trigger to a light button... but I may want to use it manually anyhow, eg on stage.

"I'd avoid fire. If only because of health and safety paperwork at cosplay conventions."
I hear you. I've been friends with some convention owners, and their rules for attractions are different usually than guests. They also make exceptions for some cosplay props. I remember one year I cosplayed Raiden while wearing a gadget that covered my body in thousands of volts of static electricity. Sparks came from my fingertips near metal. For some reason, people didn't want to give me a high five. 

Point is, I'd probably work whatever out with the head of a convention in advance, because nobody else would even know I have certain things until I'm up on stage. 

...Now I'm wondering if I may want redo how the costume attaches in the future. My current way is a black catsuit, with velcro and a couple straps. Now I'm imagining keeping guests completely in the dark that I have the full costume UNTIL the competition or showcase starts. To do so, I'd be connecting CERTAIN points to the Zero Suit Samus (her blue outfit), so I can wear it UNDER the costume... but I'd def need one that's breathable unless I add fans through my body. 

Amethyst said:

I have been wondering if there's a small LED projector, but that may be worth it's own post if not answered here.

There is the likes of the TI Pico projector

/products/roadtest/rt/roadtests/103/dlp_pico_display_pro#pifragment-4106=9&pifragment-4100=4

Amethyst said:

I have been wondering if there's a small LED projector, but that may be worth it's own post if not answered here.

There is the likes of the TI Pico projector

/products/roadtest/rt/roadtests/103/dlp_pico_display_pro#pifragment-4106=9&pifragment-4100=4

Thanks, I'll give it a go!

I updated my comment to specify, I'm wondering if there's one that can work as a reflection, eg how some HUDs on cars reflect from the winsdhield. That's what I'm imagining in my head.

Transparent OLED may be worth a look. Can look directly through it or reflect it.

Qwiic Transparent OLED HUD Hookup Guide

https://learn.sparkfun.com/tutorials/qwiic-transparent-oled-hud-hookup-guide/all

https://www.youtube.com/watch?v=8Xre5bewfVE