View Full Version : question biomech forum

08-14-2007, 11:37 PM
Dear Biomech-subscribers,

I would like your opinion on the following matter, as I don't have
enough technical background and experience:
I want to measure the speed of horses passing two pairs of
photo-electric sensors. The horses are trotting in hand (speed
approximately 3.5 m/s). The timer interval indicator I connected to
the sensors has a pulse interval measurement range from 10 ms to 3200 s.
If I place the sensor pairs 2m apart, then the horse would cover this
distance in 0.5714 s. But I can also increase the gate length, eg to
4m. Then the horse would pass in 1.1428 s. The timer has a measurement
accuracy of +- 0.08% rgd (what does rgd mean??)+- 1 digit. The horses
are trotting in a straight line of 20 m, and I am collecting kinetic
data in te central part of this runway. I would like to collect speed
data with 3 significant digits (cf the interesting discussion on
significant digits on the forum earlier this year). What gate length
would be preferable technically? (I supposed a shorter gate lenght)

Maarten Oosterlinck
Faculty of Veterinary Medicine
Ghent University