[SOLVED] Quadrature encoder pic programs

[Guest]

Quadrature encoder help

Hi all

Who knows a schematic to analog decode a quadrature encoder!?

I think about using a frequency to voltage converter, but this solution only give to me the absolute velocity, not the direction....

How can I extrat with a analog circuit the rotation direction?
the output voltage will be positive if rotational clockwise, and negative if rotation anti-clockwise

Best regards
Pendragon

 

[flatulent]

usual way

The encoder is usally alternating states, such as dark and light areas, that are equally wide. The pickup is two sensors that are spaced by half the width of the dark and wide widths.

The output of these sensors is square waves 90 degrees apart. The direction is decoded with a phase detector like the frequency-phase detector in a PLL or with sequential logic. The turns are decoded by counting square waves.

 

[sibi]

quadrature decoder

This application note from Atmel may help