What sensors are used to detect the hot LED lights on the FRC field?

[DjScribbles]

Originally Posted by tr6scott

Don,

I was thinking of doing this too, did you buy the lights the field uses, or did you have access to a field that did? Once the bot is in the bag, we are working on hot goal detection, anything you can share?

I'm also quite curious about this. It had crossed my mind, but I didn't get any further than that with the idea.

Are the individual LEDs close enough together and bright enough that they don't simply appear as individual spots of light without making the filtering stage too permissive?