Hall Effect Sensor.

[MyFeetHurt]

Hey, Stu, it's Christine. I did some calculations.

Wheel radius = 4", Robot speed = 10 ft/sec, gear by sensor has 45 teeth

2 * pi * 4" / revolution

* 1 revolution / 45 teeth

* 1 sec / 120 "

* 1000 mSec / sec

= 4.65 mSec / tooth

In other words, you can't do this by polling the sensors in a 26 mSec cycle, and you probably can't do it in the fast cycle either.

I think the right way to do this is to hook the sensors to a digital counter and poll the counter. I could be wrong. I don't know squat about counters, it's after midnight, and I can't remember how quickly the fast code cycles.

I won't be there this weekend. See you all Monday.

[Joe Ross]

You can get very similar Hall effect sensors from Newark (they are actually just the next version newer, ATS665LSGTN) for $5. So, teams shouldn't limit themselves to just the two in the kit if they want more. There were 762 in stock when I posted this.