The team I mentored in 2017 used a focusable flashlight from Amazon. It would project a square patch of light that was about 6" x 6" or 8" x 8" at 15 ’ from the light. It was bright enough to be seen from the other side of the arena. Several flashlights were tried. Some produced a fuzzier pattern. They used a voltage regulator board from Amazon to make the 4.5 V to replace the 3 AAA’s. The only downside was that the flashlights have some sort of control chip that makes it flash quickly if it was cycled on and off quickly.
Foreword: We are using a limelight, and all the below is based on the green LED on it.
We found the issue was not with the light reaching the other side of the field, but having the correct camera resolution to still see it. The zoom feature of the limelight help us, but I would definitely do some testing if you are using your own camera.
I would also like to remind people to tune for other’s lights. There were matches in 2016 that I remember people using flashlights cause other’s vision tracking algorithms to go amiss. I was at no fault of the flashlight user, but rather that people didn’t consider this as a possibility. (We sure didn’t)
The focusable lights have to be aimed strategically. In 2017, ours was aimed horizontally at a point just above or below the loading station slot so it never projected light over the top of the metal part of the driver station wall.
Last year, we had one aimed horizontally through the hole in the hatch panel.