Lasers as better finish-line emitters?
Posted: Fri Mar 17, 2017 3:04 pm
So, a recent discussion has prompted some research into light sensitivity of Pinewood Derby timers. Namely, how most timers are affected by large amounts of ambient light. Sunlight, camera flashes, etc, seem to have the potential to oversaturate the light sensors and prevent them from detecting when a car has crossed the finish line.
I've had one person tell me they've even seen timers triggered by a camera flash. I have to admit that I don't understand the physics of how that would work, but if somebody knows, I'm listening!
Anyhow, I was thinking about how most (all?) finish line detectors use infrared emitters and sensors. Perhaps there's a better way?
Laser emitters are dirt cheap nowadays. I mean, I can buy a laser pointer at the dollar store. What if we built a finish line timer that used lasers as the light source, and some kind of photo sensor that was set to require a particularly high intensity of incoming light (e.g. from a laser beam) to register?
As an added bonus, because the beam to a laser can be precisely directed, the sensor could be recessed down a small and narrow space (a tube, perhaps), to further cut down on any light pollution.
Any thoughts on this? Reasons it's a Bad Idea(tm)?
Bonus: It would also provide a cool effect as the cars ran under the laser and the beams diffracted off of them.
I've had one person tell me they've even seen timers triggered by a camera flash. I have to admit that I don't understand the physics of how that would work, but if somebody knows, I'm listening!
Anyhow, I was thinking about how most (all?) finish line detectors use infrared emitters and sensors. Perhaps there's a better way?
Laser emitters are dirt cheap nowadays. I mean, I can buy a laser pointer at the dollar store. What if we built a finish line timer that used lasers as the light source, and some kind of photo sensor that was set to require a particularly high intensity of incoming light (e.g. from a laser beam) to register?
As an added bonus, because the beam to a laser can be precisely directed, the sensor could be recessed down a small and narrow space (a tube, perhaps), to further cut down on any light pollution.
Any thoughts on this? Reasons it's a Bad Idea(tm)?
Bonus: It would also provide a cool effect as the cars ran under the laser and the beams diffracted off of them.