I got some samples of the nifty looking AS5040 10-bit magnetic rotary encoder IC from Austria Microsystems.  I want to do some experiments with these chips to possibly replace the mechanically coupled encoder I was planning to use to measure the spindle speed on my CNC mill.  The chips basically have Hall Effect sensors and signal processing internally to automatically detect the rotation of a magnet with very good precision (1024 counts per rotation, or 0.35 degrees per count!).  They can run up to 30,000 RPM, so speed is no issue for my application.  They can output quadrature like a regular mechanical or optical encoder, commutation signals for brushless motor control, or you can talk to them over a SPI bus.  Very cool!

To test out the chip (and possibly actually use it in my applications), I needed a PC board.  Laen’s service is a no-brainer when it comes to making a small board, as it’s practically free.  Here’s the little board I put together (red is top layer, blue is bottom layer (flipped).

And, if you’re interested, here is the schematic.