On theatre and actor-triggered sound effects

It's actually quite fascinating knowing a theatre director. You get to learn all sorts of things, and get a bit of an "in" to see even more stuff.

For example, I was able to see what you might call a minimalist production of “Hound of the Baskervilles” that used three males actors and a two-sided fireplace, and was later invited to usher the same show at another venue.
(we joked about starting a new theatre company called Three Men and a Fireplace. It would work! Honest!)

Anyway, there were a few scenes where one of the actors had a small plastic gun they had to fire a series of shots from, but the shot sound effects were part of an audio file played through the sound system, so they had to synchronize their hand motions to the audio file, which didn't work very often.
(well, not to me, anyway)

So I decided that there ought to be a better way to do this.

I found out that they use a program to cue up all the sounds that make up the sound effects portion of the show into a sort of audio script.
It's triggered somewhat like PowerPoint, just keep pressing a key to trigger the effects.

You can also trigger particular effects via other keys on the keyboard if your script isn't actually a single linear progression.
This is important, because it makes what I'm trying to do possible.

I also found out that you can buy a hobbyist-oriented four-button key fob and wirelessly-activated relay.

Put these two thoughts together, and you get a key fob whose relay activates a key on the guts from a USB keyboard.

Now, while you can get USB keyboards pretty cheap nowadays, there is an issue with most of their circuit boards.

The pads used to connect the board to the key matrix do not actually accept solder.
In fact, the one board I'd tried actually had the hot solder roll around on top of it, and broke right back off easily after letting it cool and harden.

Second option was to use any of a multitude of microcontrollers, small very low-end computers that are (usually) easily programmed to do simple tasks.
Well, there aren't too many things simpler than pushing a button when an input changes, so it should work fine, right?

First test was with an Adafruit Trinket, a small ten-pin micro microcontroller that has three data pins and a bunch of power pins. Useful for small projects.
Plus I was able to have it emulate a USB keyboard! =^.^=

Unfortunately, I need about six I/O pins or so (might be up to eight, I'm not sure yet), so while it was great as a temporary test rig, it won't be useful in the long run.

Because the Trinket is compatible with Arduino microcontrollers (as are many microcontrollers nowadays, much to my relief), I'm currently mocking up some software on my recently-purchased Arduino Leonardo (one of their latest official boards) before I choose a smaller board to 'port it over to.

Ideally, I want to put as much of the parts as possible into a small plastic project case so it all looks fairly professional.
(with the added benefit of preventing connections from getting bumped)

Anyway, I'd tried to show my progress to my director friend, and she and her husband (who does the music and sound effects for her shows) are both quite happy about the possibilities.
Unfortunately, due to a faulty cable, I wasn't able to actually demonstrate the project to them, but I will have a working model to show them later.
(honest! =^.~=)