Google Interview Question: How do you design an interfac... | Glassdoor

Interview Question

User Experience Designer Interview London, England (UK)

How do you design an interface for a 1000 floors elevator


Interview Answer

5 Answers


Firstly I am assuming that there won’t be any budget problem. Ok there are two options and we have to test which one is the user preferred yes I mean user preferred, with real user testing.

a)It has to be touch screen (sleek user interface with LCD screen). The interface can be like calculator (not exactly like calculator just the key part) were user can punch the key in and the output will be seen on LCD touch screen.

b)Second option > the idea inspiration comes from Apple, yes iPhone were you slide and select the fore (just like how we set date or time in iPhone)
Yes of course both the interface has to be tested, when I say tested; tested with real users.

Note: There has to be some big/or small LCD displaying on each floor (not sure about each floor) to display were the lift is going to stop. Both inside and outside the lift. Putting LCD outside the lift in a proper location will be easy but not inside. It has to be placed in L shape were the door open.
on top of the door ( \ like this) so each one can see the LCD no matter where they are standing or tall or short one ;)

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Nadeem Khan on Aug 28, 2012

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Use a dial-pad rather than an abundant amount of buttons.

Anonymous on Jan 10, 2014

I would say to let people to enter the floor number into a keypad while they wait for the elevator. This gives them ample amount time to dial in their floor number while waiting instead of having to fight over the keypad after they get into the cramped space inside the elevator. Since most people goes to the same floor every day (assuming this is an office or residential building), there can also be a companion app for employees/residents of the building. It detects that they are waiting for the elevator with a proximity sensor and already knows which floor they need to go to.

By pre-entering the floor numbers while waiting, the lift can prioritize which floors to access based on who arrived first and how close these floors are to each other. For example, if the distribution of riders falls into two clusters, then one elevator can take the riders to one cluster of floors, while a second elevator takes them to the second cluster. (This is assuming that there are multiple elevators). Then as the elevator is arriving, it will display the floor numbers it will be accessing.

This also reduces the annoyance of the person who jumps in the last minute and chooses a floor arriving ahead of yours.

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Edmund Yu on Oct 4, 2014

Most of the time, we jump start on solving such a problem from the point of view of lowest floor (street level) problem.
Instead, we need to ask some probing questions to understand the scope of the problem.

For a 1000 floor building, what is the amount of foot traffic are we talking about (on each floor)? How many elevators are in the building. What is the type of building (Residential, Commercial, Hotel etc.).

Once we make some assumptions or get answers to these questions, we can start looking at the complexity of the issue. While it is important to know the people on street level want to go to a certain floor, there are also people who are coming down and people who want to move from some floor to other floors. Hence, the solution needs to allow the elevators to generate its own paths and programmatically decide which direction it will move next.

The simplest solution would be to have a place in each elevator lobby for people to enter which floor they want to go, as soon as you enter the floor, the system will display which elevator you need to go and stand. They can either enter the floor number or use NFC based access cards (as suggested by Edmund above). Each of these (multiple) elevators can have numbers (E1/E2?E3 etc.) on each floor.

Based on the demand, the elevator logic will decide which elevator goes where and directs people to the respective elevators (to optimise its operation in terms of time, crowd management and electricity consumption).

My solution is somewhat a mix of new concepts and some earlier discussions above (as I wanted to build on others ideas and improve the solution).

Hope you like it :)

Sajid Saiyed on Jan 18, 2017

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