> That makes sense. Failure-resistant sensing
> methods are definitely better and a magnet + hall
> sensor is a good step in that direction. I would
> ask, though, what kind of precision you can expect
> with that setup. What about a magnetic angular
> encoder?
> [www.digikey.com]?
> lang=en&mpart=AS5163-HTSP-500&cur=USD
I imagine the repeatability will be fantastic. qharley's reported that this setup works great for RepRap Morgan. Of course, I will not be using this like regular limit switches. I just need to get all arms in the same orientation. I will place approximate calibration values in the firmware. I will then level the bed to match the machine's output.
I have never heard of magnetic angular encoders. Very cool. From the datasheet it says that it can achieve 16384 steps per revolution. My large wheel will have 28800 steps per revolution if I use 1/16 microstepping. 1 microstep is only changing the length between a bottom vertex and the tool by 5 microns. I think this encoder will be more than sufficient and it is only $7. However, I don't want to have to deal with the electronics to use it so I will keep this in my pocket for an even more freeform design or a design that has not steppers.
> methods are definitely better and a magnet + hall
> sensor is a good step in that direction. I would
> ask, though, what kind of precision you can expect
> with that setup. What about a magnetic angular
> encoder?
> [www.digikey.com]?
> lang=en&mpart=AS5163-HTSP-500&cur=USD
I imagine the repeatability will be fantastic. qharley's reported that this setup works great for RepRap Morgan. Of course, I will not be using this like regular limit switches. I just need to get all arms in the same orientation. I will place approximate calibration values in the firmware. I will then level the bed to match the machine's output.
I have never heard of magnetic angular encoders. Very cool. From the datasheet it says that it can achieve 16384 steps per revolution. My large wheel will have 28800 steps per revolution if I use 1/16 microstepping. 1 microstep is only changing the length between a bottom vertex and the tool by 5 microns. I think this encoder will be more than sufficient and it is only $7. However, I don't want to have to deal with the electronics to use it so I will keep this in my pocket for an even more freeform design or a design that has not steppers.