I have a few machines in my home workshop. I guess most people like me have found that the cost of the machine is small compared to the accessories you need… So I spend most of my time making accessories. I’d like some digital readouts for my machines. Problem is that they cost lots for lots of machines… Why not make some. How hard can it be? Magnetic scales seem to be the easiest way to go for the serious DIY’er Small in size, scalable to any size simply by cutting the magnetic strip and of course, relatively cheap. Austrian Micro Systems make a range of linear encoders suitable for this project. I’ve picked the AS5311 device. This device has a resolution of about 0.5um. It also has quadrature output that provides a resolution of 1.95um 1.95um is good enough for me. 0.00195mm So, how am I going to read these devices? The Arduino was my first thought. Cheap and easy to program. The Quadrature output of the AS5311 gives 1024 pulse per 2mm magnetic pole pair. I want my project to have at least 3 axis capacity. I don’t think the Arduino would cope with this on three separate inputs. After some searching for quadrature counters, I came across the LS7366R from LSI. This is a 32bit Quadrature counter with a SPI interface. Perfect. So, my sensor consists on an AS5311 and a LS7366R to count the pulses. Then, it’s just a matter of reading the pulse counter on the LS7366R and displaying the results. This should allow me to use the Arduino to process the counts and drive a display. Here’s my circuit: Circuit board time.
i would really like to see you post your design files… Im pretty much on the exact same project and that would save me a decent amount of time.
I will post code and layouts etc soon. I’ve been distracted with other projects…. The design has changed quite a bit since my prototypes. More in a few days. Thanks.
I am also very interested in building a diy dro system. What program did you use for the schematics and board layout?
Is there a board schematic available so that I could get my boards manufactured locally?
I used Eagle for the schematics and PCB layout. I get my boards made at oshpark.com. Easy to use and free shipping.
I’ll be posting an updated design shortly.
Hi, I have the as5306a chip and also the LS7366R decoder chip but I am having a very hard time with the coding. Please help
Sure. I sent you an email.
great build. however I am struggling with the type of magnetic scales you use? were to bu those. I might of missed them being discussed since I haven read all the post yet, but I really, Really like you concept here!
so were to find these.. what are they called? is it something special , or just magnetic tape…
let me know!
For testing, you can buy 300mm lengths on tape direct from AMS – http://ams.com/eng/Products/Magnetic-Position-Sensors
For about US $7.50. For longer lengths, I purchased direct from Bogen in Germany. They have a minimum quantity requirement.
There are a few other places that also supply it. The tape is multi pole tape with 1mm pole spacing. See the AS5311 datasheet for more info.
You can send me a code file to 3 axis DRO.
I want to build the same DRO and I found your project.
I’ve sent you an email with some more details.