The biggest challenge was a combination of a few things. The neutron wand was tricky since I attempted to find pieces for the body but kept failing. I eventually settled on craft plywood from Michaels which I’d Dremel into shape before glueing it like crazy with wood glue. But there was definitely a lot of wasted time trying to find something pre-made that was good enough. Secondly was the audio and wiring within the wand. I knew I wanted to have some noise come out from it and not have it completely localized in the backpack. Eventually, I settled on a cheap 5V amplifier from adafruit I had ordered a while back and a cheesy portable speaker from The Source.
Finally, the biggest issue was getting the WaveShield to behave. The library was a little finicky and I had to deal with things such as the fact it could only ever play one sound at a time and had to play it to completion before it’d read any switch states. The pack had a variety of sound states I had to individually create such as “pack turning on”, “pack turning off”, “pack idling”, “pack idling with neutron wand starting”, “pack idling with neutron wand firing”, and tweak the lengths so that it didn’t keep making noise for like 10 seconds after letting go of a button.
For those who want the sound clips, you can find them here:
Here’s the pack in action:
Prototyping the LED chaser circuit:
Prototyping the sound board:
Dollar store PKE meter:
How the cut EVA foam is layered together to make the base.
What I had managed to document on the blog about the project before life got in the way: