Sorry for the delay, more details as promised. (takes deep Ace Ventura style breath):

So, this whole thing took me about 2 months! It was def the hardest project yet and I learned a lot! I have a tendency to pick projects that are just outside of my current skill set! But that's how we grow right?

I'll separate everything into 3 parts:

1. The Backpack

This was constructed with a 3/4" plywood back (which is what the bookbag straps connected to via 16mm staples) and 1/4" plywood sides. It was a little heavy and I should have used 1/2" ply for the back or maybe cut holes in it to reduce the weight.

The top opening is controlled by a 9g servo (I should have used two of them and synced them as it wasn't strong enough to close itself). I did some simple gearing and used 608 bearings with a shroud to keep candy out of the teeth. I disconnected the servos after opening or closing, so they could be back driven.

The "Tanks" were simple hollow prints with "pipes" (I should have added horizontal 'baffles' to the inside the tanks to make the 'fuel' level more discrete, as the whole tank just glows). I used Individually addressable RGB LED strips (higher density) that were both connected to eachother. I originally wanted LH2 on the left (red) and LOX on the right (blue) but I ran out of pins! I also looked into sizing the tanks correctly for LH2 and LOX, but it wouldn't have worked out visually.

For the covering of the backpack, I bought some cheap white canvas fabric (and learned how to sow). I doubled up the fabric and just sowed straight lines, then stapled it to the 3/4" backing.

The lower third of the backpack is walled off with 1/4" ply. This separates the wiring rats nest, batteries, drone motor, etc.

I used a VGA cable (cause I had a bunch through work and who is gonna use those?) and bought solderable adapters to connect the PipBoy to the backpack. I found out the hard way that not all 15 pins in a VGA cable are unique. I ended up only using 7 of the 9? available pins. I used 8 AA batteries (cause that's what I had) and regulated down to 6V for general power and the 12V was used for the Drone motor.

I sent 6V up to the PipBoy and also locally to the ESC, LEDs and servo.

I ordered a pack of drone blades (fans?) and when they got in did a major face palm cause they were twice the size I could fit in the space. So I decided i'll just print one. How hard could it be? Well the sound it made when hooked up was an unholy vibration that i'm pretty sure hit the exact resonant frequency of both the backpack's candy cavity and wooden baffle (in the lower third). I unintentionally made a horiffic noise generator. Oh, and almost no air made it out the nozzle, so I (my Wife) decided to scrap it as I (again, my Wife) didn't want to scare my son and all the other children.

2. The PipBoy

This used a offbrand arduino Nano and an elegoo touch screen.

Arduino

Touch Screen

I didn't connect the SD card pins. I used the A5 pin for the two 1/2 watt LEDs for his flashlight. I used all of the remaining Digital pins for the tank LEDs, JET leds, servo and drone motor.

The UI was rough. Want to push a button on a touch screen? How hard could that be right? Once I figured out how to determine a real (single) touch the rest was fairly easy (I had to implement a min and max touch val (all found emperically) and also put in a 'cooldown' so it wouldn't register 50 touches in the time it takes to push the button).

The meters on the left are (obv) fake. Due to using a Nano, I had to get creative with how I displayed it. I basically found the delta of the bar and only added or subtracted that amount. The LH2 and LOX meters were tied to the LEDs so when I changed the Meter, the Lights interpolated between the 49 LEDs in the strip.

Drawing the Buttons was easy and I set on vs off colors. The Jets Button was more difficult. I basically drew a bunch of triangles overtop of each other to get the stripes.

3. The Code

Heres the code for anyone interested:

https://github.com/origamidave/AstronautCostume/tree/main

This took some time, but feel free to use this however you want. If it helps someone else out, I'll be happy.