Author Topic: Cheap Absolute Angle Sensor  (Read 197 times)

jpigg55

Cheap Absolute Angle Sensor
« on: October 12, 2022, 10:17:01 AM »
I was recently looking for a solution to a problem for an upcoming project and found one I think will work.
I realized this could have multiple uses in automation/digitizion of various metalworking application and decided to see if there's any interest in our community. If so, I'll try my best to document everything in a thread.
The basic concept is a low cost (sub $100) Absolute position rotary angle encoder with sub 0.1 degree of rotational accuracy for use with rotary, tables, indexers, tachometers, and more.
Here's links to a few of videos showing what it is and how it works.
https://www.youtube.com/watch?v=t323DEj0k_s
https://www.youtube.com/c/CuriousScientist/search?query=AS5600

FYI, both video posters have multiple videos on the subject. The "Robert's Smorgasbord" video link is discussing the Allegro A1334 chip which is now obsolete, but available. It was replaced by the A1335 chip, which he also has videos on.
Here's the Digikey link for the AS5600 sensor board https://www.digikey.com/en/products/detail/ams-osram/AS5600-SO-EK-AB/5066879 which is currently priced at $16.76. Add in $20-$40 for an Arduino and you can understand how cheap this could be made.
SB 9A, Clausing 8520, Sanford MG 612

4GSR

Re: Cheap Absolute Angle Sensor
« Reply #1 on: October 12, 2022, 02:39:52 PM »
Here's one in a compact cube with a USB cable....

https://www.ebay.com/itm/255102328735?hash=item3b65489f9f:g:7zIAAOSwM3RhILj0

Pretty much does the same thing IMO.

jpigg55

Re: Cheap Absolute Angle Sensor
« Reply #2 on: October 12, 2022, 06:45:22 PM »
Here's one in a compact cube with a USB cable....

https://www.ebay.com/itm/255102328735?hash=item3b65489f9f:g:7zIAAOSwM3RhILj0

Pretty much does the same thing IMO.
Can't say for sure since listing is no longer there, but since it was listed under the protractor category, it may not be the same.
Most of the rotary encoders I've seen listed are incremental which don't retain the absolute position although they have higher resolution in the order of 1024 positions per revolution or higher.
If that level of precision is needed then they are the way to go, but the quadrature incremental encoders I've priced run in the $250+ price range for the cheap ones and the absolute ones running closer to $1,000 or more.
SB 9A, Clausing 8520, Sanford MG 612

Carpenter84

Re: Cheap Absolute Angle Sensor
« Reply #3 on: October 12, 2022, 09:10:59 PM »
My Milwaukee 12" sliding chop saw has a digital encoder on the miter table. 0.5* resolution. I have once upon a time pondered a project that would have utilized a rotary encoder for positioning, but I cannot remember what that project was and it obviously never came to fruition - hence, I cannot remember.
But I can see how an encoder and display could be useful. On a rotary vise, for example. Or a more accurate indexer for making knobs or graduated collars, etc etc etc.
Shawn

4GSR

Re: Cheap Absolute Angle Sensor
« Reply #4 on: October 13, 2022, 08:45:01 AM »
That's weird.... the listing is still there when I open it.....

Yeah, the REAL rotary encoders are expensive and are far more accurate than the one I posted in the eBay link.  I have very little experience with the new stuff used today.  Worked with a few way back in the late 1970's.  They actually got a little cheaper since then. Back then they were a little different kind of animal from what we use today.  They had a couple of functions built in them back then.  Along with rotary positioning, they provided feedback to the controller as a resolver they called it.  The controller unit had to be adjusted exactly or the motor would not turn or turn a turn or two. As i said, I'm not up to speed on this stuff today. 
Ken

jpigg55

Re: Cheap Absolute Angle Sensor
« Reply #5 on: October 13, 2022, 03:26:57 PM »
Yeah, if I were looking for high accuracy I wouldn't use this type, currently not that accurate.
Where I can see uses for this technology would be for something like an attachment for indexing a lathe headstock that could also at as a tachometer. Since all it needs is a small radially magnetized magnet glued or attached directly, I can see using it for initial setting of a cross slide angle and possibly for positioning a mill head for angle cutting and get it close before tramming.
From what I've gathered, this is the technology the automotive industry is using for cam and crank position sensing, steering wheel position sensing, and even wheel monitoring.
SB 9A, Clausing 8520, Sanford MG 612