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

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

Amethyst said:

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.

You can keep it as simple or as feature-filled as you wish. Whatever works for your peace of mind.

I would consider doing the fan control this way because it would mean I wouldn't have to turn it on or off manually, and it would help to save battery power if it's not fully 100% constantly, you could also not have to think about controlling it.

However, you could simply connect it up with a potentiometer to change the speed. Whatever works for you, but that means putting the controls somewhere.

Amethyst said:

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. 

Larger fans are usually 12v fans, and they move more air while running at a slower revolution per minute, so it would be less noticeable than a smaller and higher-pitched fan running full speed, that's my reasoning for suggesting it.

Amethyst said:

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.

From my understanding, it can be called "forced convection" and uses "pressure differential". This can cause the force of air to increase, and cool more effectively if there is a difference in pressure, if there are more things in the way between the intake and the exhaust, you typically need more pressure to move the air.

Having two active intake fans and one exhaust fan, or no exhaust fans (simply a vent) causes a pressure difference, or having two exhaust fans, and only one active intake fan, or only intake vents, can cause a pressure difference. 

You then alter the speed at which the air moves by how fast the fans turn, in combination you get more air moving and cooling effectively.

A lot of the heat in your helmet will obviously come from your mouth and nose, so you could take the approach of having air intake at the front to counter the heat you're outputting, or immediately exhaust out the front. Perhaps a vent at the front would work, and then two or more fans elsewhere, which then will pull cool air in and over you, and expel the heat out. There may be designs online for 'cooling helmets' that could make sense and assist. I'm only spitballing ideas.

Amethyst said:

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.

I think beacon_dave's been posting good ideas on that one, I'm not sure the pico projector he has linked is still in stock or available but there are definitely small projectors and using a small OLED screen via a 'peppers ghost' type of effect can work. 

Amethyst said:

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).

I agree, that does sound cool. I had meant 'boot' as that's the term for something to take time while it loads its operating system, but I think we can disregard that concern for your idea

Amethyst said:

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.

I admit, I've done that on a hot day.

Amethyst said:

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. 

Indeed, our e14phil has/had a license for working with special effects that behave in this way too. Maybe they'll also pop into the thread with some ideas.

Amethyst said:

Also, I'm bad at the quote thing.

The site's a bit bad at being mobile-friendly, but I'm taking notes to talk with the dev' team about improving that, thanks for being patient with it. 

cstanton said:

Larger fans are usually 12v fans, and they move more air while running at a slower revolution per minute, so it would be less noticeable than a smaller and higher-pitched fan running full speed, that's my reasoning for suggesting it.

Thanks for pointing that out! I didn't know 12v ran at lower RPM. As long as there's a layer between my ear and the fan, would the higher RPM be less audible to me (since higher frequencies penetrate less), or are higher RPM fans just generally louder? There a term for the level of sound emitted by fans, or a bearing type that would be cheap but quiet?

Not having controls handy is why I was thinking of just having it plugged: IDK where'd I'd put a switch or pot.

cstanton said:

You then alter the speed at which the air moves by how fast the fans turn, in combination you get more air moving and cooling effectively.

Thanks for the explanation! Something like that was running around in my head.... I was already planning to run the airflow into the front bottom of the mask. I think I considered the breath thing when I originally designed that part. I also figured if I didn't put an exhaust, I may let it vent out down my neck. I'll look into the helmet ideas you mentioned!

cstanton said:

small projectors and using a small OLED screen via a 'peppers ghost' type of effect

This! I didn't know there was a name for it! Thanks... but do you have any ideas how I can make this work, without potentially blinding a person when it's shining light onto the helmet? I also don't need anything high res, just like ability to draw a square (for detecting people) and things like temperature or battery levels.

I remember an old arcade machine at a grocery store as a kid, it had baseball that used THIS exact technique to create an illusion that had it look like it was 3D! I'm so happy I have a way to look that up now! 

cstanton said:

I had meant 'boot' as that's the term for something to take time while it loads its operating system

So question here... there a way to play a sound file when it's still loading? EG loading the Raspian screens in memory?

All that aside, for the flash paper, it's pretty much harmless. My main concern is the ice canon.... I'd likely just keep a canister in my hand, inside my arm cannon, just for the showcase. I was just seeing if there was a better method. It uses a compressed air: If you turn it upside down, it sprays out the liquid that turns into a crystalized mist. I heard this can cause instant frostbite, so was hoping for a safer alternative. 

And thanks for the all the discussion and being a great asset to this site! <3 

cstanton said:

I'm not sure the pico projector he has linked is still in stock or available

Farnell appear to be still selling them (but 100wk+ lead time).

Buy Now

Mouser have 200+ in stock.

cstanton said:

I'm not sure the pico projector he has linked is still in stock or available

Farnell appear to be still selling them (but 100wk+ lead time).

Buy Now

Mouser have 200+ in stock.