DIY Rotary Quadrature Encoder

Neil, I think it is actually very good - If for example you were to use it for a spindle encoder for an ELS, it would be more than adequate at 0.5degree non-linearity. If used however as a 1:1 axial sensor on a rotary table, 0.5 degree error may not be acceptable..

What do you mean by absolute In terms of this device? It can give absolute angle in degrees from a calibrated zero point, give quadrature with a calibrated reference signal, and provide a 24bit PWM output related to angular position.

Regarding placing the IC in the center - I did make a automatic vacuum pencil that fits on my PCB engraver. The engraver also has a centering camera with cross hair, the idea being that I can engrave the PCB, and since the centre is then known, use the camera cross hair to center the pickup of the device and place it on the PCb with the vacuum pickup...If I were going to make a half a dozen...

Makes nice VFO tuning knob on my radio...

Joe

Sorry to resurrect a somewhat old thread but I just found this and it seems pretty impressive and also nice and small. I also see that RS sell a board with one already mounted (including a magnet).

I do have a question... I'm looking for something that can tell me the rotational position of a shaft on power up. Can these things do that or must they first be rotated to a zero position in order to 'find themselves' after power up?

The AS504x series from AMS are angular position sensors - they give an absolute angle from power on. You would obviously need to align the magnet to the shaft so that the required angle is presented.

The AS5147 I used just outputs pulses - 4096 edges per rev, with one index pulse per rev.

Joe

Excellent, thank you Joe.

I think something like the AS5040 will fit the bill... a resolution of 1/1024 of a turn which is probably a good deal more resolution than I need for this project.

I will buy one to experiment with in my next RS order.

Joseph,

Great work, I looked at those data sheets a while back to learn how sensors worked, good to see an implementation.

Adrian

Same device used for my lathe spindle encoder -