Can two racers, each with their own mini-lap receiver use the same transmitters? one at the start and one at the finish line?

The mini-laps will be attached to the bottoms of racing skateboards. the racers will be about 10 or 12 feet apart from each other - side by side. If they cross the finish line very close to each other, will one rider block the beam from the other? Or can the beam make it's way around the first skateboard to trigger the racer on the other side?

There will only need to be one transmitter to trigger as many Mini-Lap, or Ultra-Laps as you want. Each time you pass one it will trigger a lap.

For your situation, which is "point to point" I'm assuming. You will need one transmitter at the beginning to trigger the start, and one at the end to trigger the end.

You can not line up for a start right next to the transmitter or it will start the timer while you are waiting. You will have to put the first transmitter a little way down the track.

The transmitter can be blocked by other competitors, but is generally not a problem even at the high speeds achieved during road racing because of the reflection of the infrared light.

Thank you.