Switch Designs Already

       The two light switches (pictured above; one is hiding due to being painted over) and the fan knob have poor mapping. The fan knob (above the switch plate) also has poor control signifiers. Norman states that "[b]asic switches and controls should be relatively simple to design well. But there are two fundamental difficulties. The first is to determine what type of device they control....The second is the mapping problem...." The light switches have poor mapping because the light switches on the far left do not turn on the lights on the left side of the room. The same goes for the light switches on the right. Also, since there are two light switches, a user does not know which panel is for the room and which one controls the lights outside. The lights in my house also have a constraint, not allowing the user to make the lights brighter or darker through a dimmer. The fan has poor mapping because it appears as though it is a dimmer for one of the lights due to it's proximity to the light switch plate. Norman mentions that the closer objects are to one another, the more likely a user thinks the controls are related. The fan knob has poor control signifiers because a user cannot tell that it turns on the fan and it doesn't display a signifier that tells the user how to make the fan go faster.
       There are a few solutions to the light switch and knob usability problem. One way that the knob could be more usable is by putting a picture of a fan on the plate that tells the user how to make the fan go faster. This signifier would also let the user know that the knob controls a fan. The designer could have eliminated the constraint of only being able to start at a slow speed by allowing the knob to turn left from the starting position. The light switch mapping could be fixed by what Norman did in his home by having a box-like figure come out of the wall. However, another solution that would make the lights more usable for the user would be to place signifiers under the light switches or just make sure that the switches on the left side of the panel turn on the lights that are farthest left in the room and the light switches on the right side of the panel turn the lights on in the right side of the room. The light switches should go in the order in which the lights are placed in the room so mapping is afforded.