Why are there 2 buttons on outside of a lift?

413x

413x

413x

Caporegime
Joined
13 Jan 2010
Posts
33,397
Location
Llaneirwg
One for up amd one for down?

No matter what i press it seems to affect nothing once you go in and further select a floor?
I understand the idea is to push down if you are traveling to a lower floor?
 
I think the lift will pick you up if it is on the way down (for example) with passengers and you are also going down. But if you were going up it would drop them off first and come back for you.
 
if you were on the second floor and wanted to go up and it is going up already it will stop for you. however if you are going down it will go past you, go up and then come for you after those passengers have been dropped off.
 
Last edited:
Well let's say you have 5 floors.
The lift is at the fourth floor and someone gets in going to five
Someone's at the third floor who wants to go to five


It's more efficient to go down to the third floor then up to five than it is to go up to five then back down to 3 then back up to five.
 
RomanNose said:
Well let's say you have 5 floors.
The lift is at the fourth floor and someone gets in going to five
Someone's at the third floor who wants to go to five


It's more efficient to go down to the third floor then up to five than it is to go up to five then back down to 3 then back up to five.
Click to expand...

That doesnt work because the lift doesnt know what floor you want to go to, it only knows you want to go up. The guy on the 3rd floor might only want to go to the 4th floor.
Priority is always given to whoever is in the lift at the time. So, in your example, the guy who gets in on the 4th floor and wants to go to 5 gets taken to 5th floor first. Then the lift goes for the other guy.

If the guy on the 3rd floor gets in first, the lift will stop at the 4th floor on the way up to pick up the other guy, because he is travelling in the same direction as the lift.
Pressing the correct direction means that when the lift stops to pick you up, it will always be travelling in the right direction and you never get that annoying thing when you get in and it goes the opposite way to what you expect. Unless theres somebody with you who doesnt understand it and presses both buttons thinking it makes the lift come sooner :rolleyes:
 
Last edited:
muon said:
I get annoyed by people who press both buttons.
Click to expand...

Unfortunately the world is 80% idiot

These people will press both buttons just in case and then get annoyed when the lift they get into goes the wrong way. Had they simply applied logic to the scenario we would all be in a happier place.
 
al4x said:
I did that :-P just cause i have a burton fettish tho.. I enjoy seeing them light up :-P
Click to expand...

Get in a lift with someone on a building with lots of floors and press for every floor. Video reactions and post on youtube.
 
touch said:
That doesnt work because the lift doesnt know what floor you want to go to, it only knows you want to go up. The guy on the 3rd floor might only want to go to the 4th floor.
Priority is always given to whoever is in the lift at the time. So, in your example, the guy who gets in on the 4th floor and wants to go to 5 gets taken to 5th floor first. Then the lift goes for the other guy.
Click to expand...
That sucks then, because it would be more efficient going down first regardless if he was going to the fourth or fifth floor.
4-5
5-4
4-3
3-4
vs
4-3
3-4
4-5
 
That's why buildings now have clever lift systems where you select what floor you want before entering a lift. Every office I have been to, has them.

However, I find they don't always utilise all the lifts instead preferring to fill up lifts in a single direction.
 
RomanNose said:
That sucks then, because it would be more efficient going down first regardless if he was going to the fourth or fifth floor.
4-5
5-4
4-3
3-4
vs
4-3
3-4
4-5
Click to expand...

By that logic, if the elevator picks up the person on the 4th floor, then goes to 3 and picks him up, goes to 4 again but a new person is on 3, it should go to 3 and pick him up, then once it goes back to 4 another person on 3 could show up wanting to go to 5 etc....

It would end up in endless loops, people being on the elevator for extended periods of time and potentially never getting to the proper destination if it keeps going back for more before it reaches the destination. Or what if the person on 3 actually wants to go down but pressed up, should the elevator go down to floor 3 only to pick up a guy who first has to go to 5 before going down to his floor 2 or 1 destination.
 
Last edited:
RomanNose said:
That sucks then, because it would be more efficient going down first regardless if he was going to the fourth or fifth floor.
Click to expand...

Overall, yes it would be more efficient but it doesnt make a fair wait for each person.
If you tried this algorithm in a busy building with lots of floors, you would find that the lift would go up and down between the middle few floors and people at the very top or bottom would have to wait a long time.

There has been masses of research into lift algorithms and the system we have now is the best balance between overall efficiency and equal waiting times.
 
Interesting factoid: On 90% of lifts the "close door" button doesn't actually do anything. It was eliminated decades ago, but they leave the button there because people like to feel they have the power to control the doors. That's why when you punch it (to speed things up) it never does anything for a few seconds anyway......it would have closed by itself after the same length of time :)

I heard this on the radio the other morning. This in the US....may not be the same over there.
 
Curio said:
Interesting factoid: On 90% of lifts the "close door" button doesn't actually do anything. It was eliminated decades ago, but they leave the button there because people like to feel they have the power to control the doors. That's why when you punch it (to speed things up) it never does anything for a few seconds anyway......it would have closed by itself after the same length of time :)

I heard this on the radio the other morning. This in the US....may not be the same over there.
Click to expand...

There are some people who have said that the close door button can be used on some elevator as part of an 'override' way of skipping past floors that would normally be stopped at, such as for police/security to go directly to where they want. No idea if there is any truth to that though or what sort of button press combination would be required.
 
Curio said:
Interesting factoid: On 90% of lifts the "close door" button doesn't actually do anything. It was eliminated decades ago, but they leave the button there because people like to feel they have the power to control the doors. That's why when you punch it (to speed things up) it never does anything for a few seconds anyway......it would have closed by itself after the same length of time :)

I heard this on the radio the other morning. This in the US....may not be the same over there.
Click to expand...

My lift must be in the 10% then as it definitely closes quickly when I press it.
 
You must log in or register to reply here.
Back
Top Bottom