So, the MCOM worked great. Much fun was had by all, and the box (due to its rather odd siren) was christened: Captain Quack.
It’s a 600x400x400 box built from softwood and 6mm ply, with aluminium edging and stainless steel corner covers. I was pleased with the look. Inside, I had a steel-lined chamber at the bottom of the box with vents between it and the outside. This is where the pyro was loaded, and also where the siren was mounted so that the sound could escape better.
The upper chamber contained the rest of the electronics, and enough space to put other game objectives if desired. There was a removable panel at the bottom so that the steel-lined chamber could be accessed to set the pyro. This was secured using cupboard magnets that I enhanced with some neodymium disc magnets for a more secure hold.
Unfortunately, I forgot to take a picture of it when I finished, and during its second outing, a slightly-more-powerful-than-I-expected pyro did a bit of damage.
Anyway, hopefully, you can tell from that picture how it looked before its misadventure!
It performed really well. The first game day there was an annoying bug where the timer would stop itself running. I’m pretty sure that the cause was a short, or some kind of capacitance effect. The box housing the electronics is a metal one, and although I lined it with tape, I think the pins at the bottom of the boards were poking through. Adding better insulation to the boards solved the problem.
After that, the electronics have worked flawlessly: before and after the pyro that blew it to bits 🙂
For the next version, I’m going to make the steel lined chamber more robust by getting rid of the removable panel and securing the top of the chamber more robustly. The top was completely forced off its mounting: the force of the explosion managed to push out eight 3/4″ screws, as well as blowing the ends and bottom off the box. To secure those, I’m going to screw them to the frame rather than pinning them. I’m also going to replace the vents at each end with a mesh screen.
Hopefully, a more robust steel lining combined with more ventilation at each end will allow the pyrotechnic’s gasses to escape at each end without doing any damage.
Since seeing it in action, I’m also going to add some new safety features: there’ll be a new piezo siren to sound when the explosion is 10 seconds away, the button will be disabled at that point, and we’ll brief players to stand clear when they hear the change in tone. I’m also going to add warning notices at the ends of the box.