For a project I need to know the exact (absolute) angular position of a turning axle with a resolution of exactly 1 degree. There are many rotary encoders or magnetic sensors, but they all have a (360/2n) resolution and I need exactly 360 positions (so a 1 degree resolution). I already made a gray-code disk with 360 positions, but I can't read it well with IR-reflection. A single track gray code could be a solution, but I don't know how to make a 9 sensor, 360 position single track gray coded disk I also can't use a AS5040 for example, because the shaft comes out of a gearbox, and the other side is connected to a turntable (model trains).
Is the AS5048 Magnetic Rotary Encoder useful? It has 360 degree angle precision sensor with 14-bit resolution. The IC measures the absolute position of the magnet’s rotation angle.
@ b4ip: Like I said, I can't fit a magnet to the bottom of the axle, there is a gearbox.
@ jremington: When I use a 10bit for example, I always get 360/210 = 0,3515 degrees, so I can never position my turntable at 17 degrees for example. This is why I prefer a sensor that gives me the exact location in degrees where it is (or in 0,5 degrees).
My error tolerance... I think about 0,1 degree. I'm using a stepper to control it, so when I have the location I can position it exactly.
For the 10 bit example:
0.3515 degrees x 3 = 1.055 degrees, within your error tolerance.
0.3515 x 48 = 16.87, which differs from 17 degrees by only 0.13.
A 12 bit absolute encoder will position to within 0.088 degrees.
servewouters:
I'm using a stepper to control it, so when I have the location I can position it exactly.
So you just need a mechanical reference point (micro switch or ANY low res absolute encoder).
And write to flash a few seconds after you have turned the table.
Leo..
I also can't use a AS5040 for example, because the shaft comes out of a gearbox, and the other side is connected to a turntable (model trains).