This may sound a little bit silly though.. but I do hope you guys can give me a little bit of tips if u do have any? :)

Which kind of optical encoders you think is the easiest to use if I am to connect to a micro?

The term "use" perhaps can be explained in terms of:

  1. sizing flexibility
  2. mounting method
  3. wiring work

OH! and I do have another question for the reflective sensors!

Do you guys know why some of the small reflective optical sensor recommends ROP of 11mm? especially AEDR family ones.. Maybe in case of space constraint, where a small code wheel is needed, Can I just shorten the ROP to less than 11mm, but of course still maintaining the recommended LPI?

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    \$\begingroup\$ I hate abbreviations that are jargonesque in nature. \$\endgroup\$ – Andy aka May 28 '14 at 8:11

Radial encoders of high resolution can have a wide range of linear codes depending resolution, speed and thus frequency response of the optical system. Both reflective and transmissive methods work well.

HP>Agilent> Avago> has pioneered high resolution optical encoders in both methods. Since the geometry of circular area detectors and radial lines has a distortion or crosstalk between dark and light, there are good reasons to standardize on the smallest wheel size to support a wide range of resolutions from 100 to 2000 pulses per revolution. This standard optical radius is called the Rop. At one time a 1" diameter was standard or Rop of 0.5" newer reflective glass and metallized wheels from Avago use 11mm.

Their smallest solution uses precision reflective optical technology with a 1mm gap on an 11mm radius wheel. The size and cost reduction of the optics is the significant difference, while maintaining the same resolution.

Of course you try to make your own smaller diameter wheel, but at the cost of lines per mm , LPmm and then compromise in radial to linear error which results in lower signal to noise and higher detection error rate with dust. The limitation is determined by spot size of emitter & detector areas.

CPR = LPmm x 2π x ROP , Where CPR = Counts Per Revolution

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