<IT programmer mode>
Occasionally (not always) I see the new gates sometimes have erratic delays in opening their gates.
Sometimes when I run up to them, they hesistate, and open half a second later.
Other times, they whoosh open almost immediately.
I wonder what is causing this variable hesitation:
-- Variable processing loads in the firmware?
-- Internal poll delays?
-- Light reflections in sensor?
-- False-detection algorithms (e.g. fast moving legs versus reflections/shadows)?
This is important; a person late for work, jogging briskly at 5 meters per second, a 1ms difference means 5 millimeters difference (1/1000 of 5 meters equals 5 millimeters). 10 milliseconds delay means the person has moved forward a massive 5 centimeters forward. That can mean the difference between whoosh-through or "whoa! doors are not opening". Now, 100 milliseconds delay means.....yep..... HALF a meter!
Even if you're moving slowly, at a brisk walk, that's still many centimeters. People's brisk walk speeds are extremely precise (they often vary less than 5%). So don't vary the door-open behaviour by more than 5%. If the doors are not predictably open by the time you're about to crash into them, then the doors aren't really "feeling" reliable.
I hope the door programmers aren't using really bad polling like:
Code:
// Dumb, simplified computer programming example
while (sensor.Tripped == false)
{
Thread.Sleep(100); // wait 100 milliseconds
}
Doors.Open();
That would add a variable delay like [0..100] milliseconds. That is bad. 100 milliseconds erraticness is too big, and right now the door-open delay is more erratic than this today -- I'd daresay the erraticness of delay can be up to 300 milliseconds.
Door opening delay ideally should be millisecond exact, to feel predictable. However, even 50ms is superior to the current 300ms-500ms range of unpredictability. Just a mere few milliseconds is actually human perceivable -- the difference between whoosh through the doors and suddenly stopping your movement to wait for the doors to open. A variable delay can make it extremely hard to choose a speed to go, that you would trust the doors to open-on-time by.
Right now, they're rushing a deployment, but ultimately, the firmware should be refined over time.
The good thing is, they are firmware upgradeable remotely (well...eventually). The hardware is probably fine, as long as they behave like the whoosh moments.
Also, some resonant-vibrating-compensating algorithms should be added to the wide wheelchair doors. Basically, intelligently modulate pulses to the door-open/close servo motors to prevent bouncy opening-closings. They'll also open/close faster as a result. The mass of the doors is known, so you can pre-program a known motor-pulsing algorithm to more smoothly open the mass-laden wide gates without the bounciness I see.
</IT programmer mode>