Some examples I have observed around the house and the city of San Francisco...
_conceptual model
original design:
I had a difficult time trying to open this door when I first moved into this apartment. It took me 5 minutes trying to figure out how to open it. The knob is there but when you turn it, the door won't open. Another try was to turn the knob on the top, but still wouldn't work. Then tried to turn both knobs, then the door finally opens. I found that I would have to turn the top knob and the door knob at the same time. The trigger on the top moves up and down to lock/unlock the door. It was confusing, but now I've gotten used to it. But for someone who doesn't know how to operate it, they could get locked inside when there is a disaster.
improvement:
Make it simple. A knob should be there to open the door when you turn it. The locking device should be a separate object and function.
original design:
This has got to be the worst design ever for a shower control. There is no indication or visibility for how to make the water come out of the shower. You'll never guess how you turn on the shower. You reach under the faucet, grab the part where the water comes out and pull down on it! This design is bad for a number of reasons. One is that nothing else works like this. Another is that the "control" for turning on the shower doesn't look anything like a control, so the control is basically hidden.
improvement:
Make the shower control visible to the user. Instead of it being underneath the faucet, there could be a button or knob on top of the water control handle or on top of the faucet head.
_contraints
original design:
This isn't quite the ordinary pencil. Say, you've gotten yourself this mechanical lead pencil and you figured that when you press the top, there would be something to stop the lead from going all the way out -- but with this, there was no constraint to stop the lead from going out when you are pressing the top, the end result is a broken lead from falling out.
improvement:
There should be something to stop the lead from going all the way out like the way the regular mechanical pencil is designed. One click should get a reasonable length of lead to come out, enough to be able to write.
_mapping
original design:
This image is the intercom buttons in front of an apartment gate. This illustrates an example of bad mapping because it does not let the user know which button is for which apartment. It is so badly designed that the numbers had to be written to indicate the designated number---furthermore, the numbers are not even written in order. Imagine if the numbers weren't written and all there was just the buttons, we would never know how to use it or even contact the person to let us in.
improvement:
The way we could improve this is to either design the buttons descending from 1 through however many numbers or from left to right.
original design:
This stove is an example of bad mapping as well because we have to assume that the right knob is for the bottom right, the second knob from the right would be for the top right, and so on. It is not natural mapping to the way we would perform it naturally---say, if the icons indicating the locations weren't there.
improvement:
The way we could improve this is to design it the way the locations of the burner were designed. In other words, bottom left, top left, top right, bottom right.
_feedback
original design:
An example of bad feedback in a power strip because it is already a red switch, there is no indication whether we know we are switching it on or off. No light to indicate power or even a label saying on/off.
improvement:
The way we could improve this is to provide lighting or some kind of sound to indicate the on/off.
original design:
Good feedback. It lets the user know when the button is on by the green light when he/she pushes it. When the user pushes it again, the light turns off.
