Fall 2005»CSCI 380 Homework 1 Crosby

CSCI 380 Homework 1 Crosby

Keddaris Crosby
CSCI 380
Sept. 20, 2005

CSCI 380 Homework 1

1. Introduction


  • It looked very modern, but simplistic. Because the interface wasn't cluttered with the unnecessary uselessness that the majority of the car radios out there suffer from(i.e. - faceplate art, buttons/knobs to change font & background color of the display, etc.), the learning curve for the basics was small and very welcoming.

Minimalism is the key to a good car radio interface.

Attach:85R589.jpg Δ Example of a car radio with unnecessary clutter.

  • To control the volume, there's a knob to turn. It was incredible how my brain saw this knob, and instantly thought, "Aw! Use that to control the volume."
  • There's a big button that says "Source." I instantly knew that was the button I use to switch from the radio mode to CD mode.
  • The slot loading cd drive was a great idea. It eliminates the need to fondle with trays and such - not generally a good idea to do while driving.


  • There's a slide button thing that's wrapped around the knob. It was a little tough to associate this slide button as a widget to change the radio frequencies manually and automatic in radio mode, and as a widget to fast-forward/rewind and skip back and forth between tracks in CD mode. My conceptional model of these actions delineates between these actions by having separate buttons/knobs to do them in each mode.

Attach:radio2.jpg Δ The slide button thingy around the volume knob caused some confusion.

  • There's a button titled "sens" that I'm unclear to what it's function is right off the bat. To this day, I've never used it. Why use something that seems useless?

2. Functionality

The car radio has the following basic functionality: listen to the radio w/ the ability to set presets for your favorite stations (includes FM & AM), listen to audio CDs w/ the ability to skip and scan tracks, displays an assortment of information (including - time, radio frequency, CD track #, and time a CD track has been playing). Includes a basic equalizer and the ability to adjust where the sound is outputted (i.e. - rear, front, left and right).

3. Tasks

Turn the car radio on. Listen to the radio. Switch between AM and FM. Save favorite radio stations somehow for quick access. Put in CD and listen to it. Change the track the CD is currently playing. Seek/skip to other tracks on the CD. Put in MP3 CD and listen to it. Seek/skip to other tracks on the MP3 CD. [Easily] read of the track names off of the MP3 CD. Put in cassette tape and listen to it. Rewind/Fast-forward thru a cassette tape. Check the time. Set the time. Change the volume. Adjust the bass/treble.

A user from an older generation may be more adept to using cassette tapes, more so than CDs and MP3 CDs; on the contrary, a user from a younger generation may be more adept to using CDs and MP3 CD, more so than cassette tapes. It's hard to know which generation the user will be apart of, therefore the question on whether the functionality of this device is greater, equal, or less than what the user needs is subjective. However, because this device only supports CDs and excludes cassette tapes and MP3 CDs, it has found some common ground between this generational problem. For that reason, the functionality of this device is equal to what the user needs.

4. Usability Breakdown

The task I attempted was to set the clock.

  • I looked for a button or text on the face of the radio that insinuated "use me to set the clock." After about 2 minutes of scanning all the buttons/text, nothing.
  • I tested out all the buttons (from left to right) by pressing and holding them to see what happens. After a few minutes, the 'display' button did the trick. The hour's digit was blinking.
  • Since that slide button was used to scan/seek thru tracks, I assumed it would function the same way to adjust the clock digits. So I moved it up and down . . . nothing happened. I tried the volume knob, and it correctly adjusted the hour's digit.
  • I pressed 'display' again, thinking it would automatically go from hours to minutes. It resulted in the hours digit no longer flashing. Apparently that's how you finishing setting the clock. I got the hours digit flashing again, and pressed the 'mode' button, thinking it would go from hours to minutes and again, the hours digit stopped flashing. I got the hours digit flashing yet again, and thought, " What the heck." I pressed the 'sound' button. It worked. The minutes' digits were flashing. I set the minutes, pressed display, and the clock was set.

5. Analysis

Visibility was violated.

  • There was a display button, and when I used it, it did what I expected it to do (i.e. - display info about the clock, CD track #, radio frequency, the time a CD track as been playing). There was nothing that visually made it obvious that the display button, when held down, is used to change the time. Likewise, when I pressed the sound button, it was obvious that it would bring up options to adjust the sound. I would never intuitively think that pressing the sound button would enable you to adjust the minutes.

Consistency was violated.

  • A "sound" button should only be used for sound-related functionality.

6. Improvements

Definitely separate controls to adjust/set the clock. Or maybe instead of the sound button being used to switch from hours to minutes, use the Source or Mode buttons (preferably the Mode button). Going from hours to minutes is like changing the mode of adjustment, or the source in which you're adjusting.

Certification of Authenticity:

I certify that this submission is entirely my own work, as per course collaboration policy.

Signature: West K Crosby Date: 9/20/05