As mentioned earlier, I just got a Laserlyte training target, and while it was really fun it was acting a bit balky. Sometimes the reset sensor would not register, sometimes hits would not register, sometimes the display would not go. And when I took it apart I found that while the batteries did have a tendency to come loose that was not the problem.
No when trying it out in my workshop I realized something... the light in my living, room for some reason, is '"icky" for the sensors. But in my workshop the thing works flawlessly.
I think the bugger's really sensitive to ambient light. The laser light from the chamber piece does have to go through a thick semi-transparent red sheet on the cover of the target to reach the sensor array.
I'm also kicking myself for not taking a picture of the thing disassembled. The way the grid of sensors is laid out for the target is really neat. There's over sixty in the target circle alone. Gives rather good resolution all in all.
So in short, if you get one of these things and it starts being balky... try a different room.