Sunday, November 23, 2008

ATM User Interface

ATMs - a convenient fixture of the modern world. Fast cash. Reasonably safe and secure (even if they can't figure out voting machines worth a damn). Awfully nice if you can find one that has no fees (as I can at my workplace).


Here we see a glaring example of poor design. The ATM dispenses cash in incremements of $20. The daily maximum one can withdraw from an ATM is usually $200 or $300, depending on the bank and the ATM. So, the number of possible input values is pretty small - you could count them on your fingers: $20, $40, $60, ..., $200. And yet, when I want to enter in my desired withdrawal of $100, I need to enter 1-0-0-0-0 on the keypad. Not only the zero after the twenty-dollar increment, which is superfluous, but also the cents as well. Since the machine is utterly incapable of dispensing change of any sort, why bother displaying or entering the cents amount at all. It seems to me that, to ask for $100 dollars from an ATM machine, I should need only press '1'. It can't be one dollar, or ten, or one thousand - '1' should only mean $100 within the rules of ATM machines.

Or, since the machine directs you to enter the amount in incremenets of $20, perhaps it would be better to simply ask: how many $20s do you want?

There are also those eight keys: four on either side of the screen. Some other, more intelligent software designs utilize those to give the user a few typical choices: press this button for $20, this one for $40, etc., and not even bother with the numeric keypad. Sure, eight keys can't give you all the possibilities, but could probably cover 95% of requests.

Even though I am an engineer, I wouldn't claim to be a guru of user interface design; perhaps if I did more software programming. Even so, I like to think I can recognize good design when I see it, and bad design when it smacks me upside the head - most everyone can. After all, it's supposed to be intuitive, isn't it?

1 comment:

Martha said...

how about the brail? especially on the drive up ATMs =)