How to use a USB keyboard to simultaneously send a keystroke to 2 computers and flash a light w/o modifying computers?
Basically, I need to press a key on a keyboard which will start a video clip that participants will watch being displayed on one computer, simultaneously trigger a keystroke on the second computer to establish a timestamp for the physio acquisition, and flash a light on the video so that we can time sync participant behaviors to patterns we see in the physio data.
Preferably I would like to assign different keys to multiple different colored lights to allow us to signal all of the different events in the study (3 on/off events, so 6 keys/lights).
I should have USB keyboards at my disposal that I can hack, but I can't touch the actual hardware of the computers. I've read the only instructables I could find having to do with something like this and those projects used the Caps, Num, and Scroll locks. Although that solution would work for controlling the lights, I don't think I can easily assign those keys to the software programs we're using to control the needed functions on the computers.
If there is a commercial product that will do this and that is a reasonable price, I can probably buy it rather than try to build it, but it seemed like a fun project to try to tackle and I can't think of anything commercial that would fit the needs I have without being way overbuilt and expensive.
I can solder and have plenty of tools at my disposal. I've worked with an arduino one other time on a project and got that working, but I'd be at a complete loss for programming the thing for a situation like this. I'm guessing the solution is going to include one of those...
Looking for links, ideas, etc. I may be in a little over my head, but you only learn by doing, so I appreciate the help!