The TriggerTrap has enjoyed some success as a way to control your camera through either a dedicated piece of hardware, or a specific smartphone app. You can use it to trigger a camera shutter based on time, light, sound, or any of a number of different parameters. But now the folks at TriggerTrap have repurposed the set up for a slightly different task: firing the flash.
The TriggerTrap Flash Adapter will set you back around $30, and does for flashes what the original TriggerTrap did for cameras. So why would you control the flash directly, rather than just having the camera set the flash off for you? Because this way you can get much higher speed photography.
Using the TriggerTrap in its normal way gives enough of a delay that capturing really fast moving action is extremely difficult. With the flashes controlled by the TriggerTrap, you can instead darken the room, start a long exposure, and then use a flash burst to illuminate the action. It's a technique not far from what was used in these incredible astro photography wedding shots.
In the explanation below, you can see exactly how and why this new setup works. Meanwhile, the smartphone apps have been updated to overall work faster, as well as to take better advantage of the Flash Adapter.