How can we solve the ambiguity and improve interaction of the elevator controls?
What are user interpretations of existing button interface?

Lot of research has been done concerning to the algorithm of elevator function, reduce waiting time of the user, design of elevator buttons, etc. In the context of algorithm for elevator function, it is defined depending on the number of floors in a building. Odd, even floor functioning lifts are observed in corporate offices. There is anoher algorithm that places half the lifts on the ground floor when inactive and other half on the top floor, experiments have done to keep some inactive lifts in a middle floor. In order to reduce waiting time for user, a researcher claims installation of mirrors for user engagement. Different installations have been tested concerning to the design of elevator call button. The gap is that not all users understand the meaning of up-arrow call button function:
Some users press the up-arrow call button thinking it will call the lift up to their current floor, and then he can go down; This contradicts with the actual meaning of the up-arrow call button - to be pressed when you need to go upwards.

Fishbone Analysis

Design goals

Improve the interface of the lift system so that it conveys the right meaning to users
Avoid mismatch between hall button entry and floor entry inside
Visibility of system status - lift's route and number of stops; Help user plan his journey
Ensure the lift doesn’t stop when it is already full
Accomodate call cancellation outside lift

Proposed solution - 1

Redesigned the existing hall button interface with no technical changes in the working of lift. The proposed interface is easy to understand, hence avoids misinterpretation. Hence, unnecessary stops due to confusion of hall button symbol is reduced.

Merits:
- Simple and cost-effective way to solve the problem of misinterpretation of Hall Buttons
- Minimal modification to the present system is required. Only the end user interface needs to be changed; machinery of the lift remains the same

Demerits:
- Does not solve the problem of mismatch between hall button entry and the floor entry inside
- Is not effective in reducing waiting periods

Proposed solution - 2

The following interface indicates the interaction between user and the elevator system outside the lift. He can choose the destination floor, cancel the call, and know the status of the lift and it’s journey for the next two floors. The user has to give a single entry, so there is no question of mismatch of entries before and after getting in the lift. The user can no longer cheat the lift. The elevator control system receives information about the destination floor beforehand, hence making it easier to plan. Sensors are provided so that the lift doesn’t unnecessarily stop when there is no passenger waitng and when the lift is full.

Goals achieved:
- No mismatch of user entries
- Usability of interface is high
- Senses the waiting passengers
- Visibility of system status - route
- Call cancellation available
- Unnecessary stops reduced
Problems:
- Installation is difficult, will require complete change of existing system
- All controls are given outside the lift - there is a possibility of misuse

Research question

User frustrations - Outside Lift

Design goals

Proposed solution - 1

Proposed solution - 2