Wheel driver and portable electronic device having the same

A portable electronic device comprising:

• a pattern wheel driver;
• and
• a microprocessor configured to display information on a display based on a signal received from an encoder,
• wherein the pattern wheel driver comprises:
• a rotatable pattern wheel with patterned regions repeatedly formed on the pattern wheel, each of the patterned regions having a plurality of patterns, wherein each pattern of the plurality of patterns has a different width;
• only a single photodiode configured to detect the plurality of patterns, the single photodiode mounted at a position where the patterned regions of the pattern wheel pass when the pattern wheel rotates;
• the encoder configured to produce the signal indicating whether the pattern wheel rotates in a forward direction or a reverse direction based on signals produced by the single photodiode;
• and
• a housing assembly configured to rotatably mount the turn dial, wherein the single photodiode is fixed in the housing assembly so that it can detect the patterned regions of the pattern wheel,
• wherein each of the patterned regions has at least one of at least three reflective sections with differing widths or at least three non-reflective sections with differing widths.