Translating Rotary Motion Into a Two-Channel Output
The HEDR-5300 series contains a Light Emitting Diode (LED) light source, an integrated circuit with detectors and output circuitry, and a reflective codewheel. The LED and detector are mounted in a single IC package which contains two lenses molded into the top. The lens over the LED focuses light onto a reflective codewheel that rotates above the emitter and detector. Light is either reflected or not reflected back to the lens over the photodetector IC.
    As the codewheel rotates, an alternating pattern of light and dark that corresponds to the codewheel's pattern, falls upon the photodiodes. This light is used to produce internal signals: A and A' and B and B'. As part of the "push-pull" detector system, these signals are fed through comparators that are part of the signal processing circuitry to produce the final outputs for channels A and B, which are two square waves in quadrature.

Quick and Easy Assembly
With the HEDR-5300, the emphasis is on easy assembly. The encoder was designed to be quickly mounted to a motor. Power and signal connections are made through a standard four-pin connector located at the top face of the encoder's cylindrical housing. The HEDR-5300 is ideal for applications such as printers, plotters, and other motion control systems.

Detecting Linear or Rotary Motion
The HEDS-9730 makes it possible to have sophisticated motion detection at a low cost. The C-shaped emitter/ detector module, when coupled with a codewheel, translates rotary motion into a two-channel digital output. When the module is paired with a codestrip, it translates linear motion into a digital output. Typical applications include printers, plotters, and office automation equipment. The standard HEDS-9730 is designed for use with an 11 mm or 23.36 mm optical radius or a linear codestrip.

Integrated Phasing Technique
The module contains a single LED as its light source. The light is collimated into a parallel beam by a single lens located directly over the LED. Opposite the emitter is the integrated detector circuit consisting of multiple sets of photo detectors and the signal processing circuitry needed to produce the digital waveforms. Because of the light source and a unique photodetector array, the module is extremely tolerant to mounting misalignment.
      The codewheel/codestrip moves between the emitter and detector, causing the light beam to be interrupted by the codewheel/codestrip's pattern of spaces and bars. As the photodiode outputs are fed through the signal processing circuitry, two comparators receive these signals and produce the final outputs for channels A and B. Because of this integrated phasing technique, the digital output of channel A is in quadrature with channel B (90 degrees out of phase).

Conclusion
Hewlett-Packard's HEDR-5300 and HEDS-9730 optical encoders offer two-channel output, high performance, low cost, and small size for high-performance motion detection.