SparkFun Forums

[rasafras]

Chips and corresponding magnet:
http://www.austriamicrosystems.com/eng/ ... c-Encoders
https://www.arnoldmagnetics.com/v2/sale ... spx?id=222

These are cheap SMD ICs that can sense the rotational angle of a magnet with 10-12 bit resolution (and accuracy), and they seem extremely easy to interface with and use. It would be nice to have the magnets and chips available from the same place, as well as a breakout board with mounting holes and the chip already on it, to make external alignment easier (the better the magnet is aligned to the IC, the more accurate it is). The only product I could find that uses these chips is a US Digital encoder that has a huge markup for low unit counts:
http://usdigital.com/products/encoders/ ... /kit/mae3/

Anyway, hope you guys find this worth looking into, they look pretty nifty for hobby robotics.

[phalanx]

Electroswitch makes encoders based off of Austria Microsystems ICs.
http://www.electro-nc.com/oak/pdf4142.pdf

They are in the same ballpark for price as the one you listed. I've used the electroswitch encoders in ruggedized military applications and they hold up very well to harsh environments (as does most everything else they make)

http://search.digikey.com/scripts/DkSea ... ctroswitch

-Bill

[fenn]

how do you know the electroswitch unit is based on the austria microsystems chip?
I just want the chip on a board, not some big thing that pretends to be a potentiometer or optical encoder.
using quadrature position output neglects the one big advantage of magnetic encoders, which is that you can ask the sensor "where are you?" whenever you feel like it and get back a precise answer, without having to constantly monitor quadrature signals and keep track of where it is. supposedly the as5046 works up to 10,000 rpm, so you'd have to sample at 4MHz for equivalent speed and resolution with a quadrature interface. (however it won't do both that speed and precision at the same time.)

the austria products also actually have datasheets, which are a plus.


also I would like to nominate AS5011 "2d magnetic position sensor" as neat toy of the day

[phalanx]

how do you know the electroswitch unit is based on the austria microsystems chip?

I had a phone call with an engineer at Electroswitch since their datasheet doesn't provide any information on the absolute version of their encoder. They refered me to the Austria Microsystems magnetic encoder ICs to get the information I needed.

I just want the chip on a board, not some big thing that pretends to be a potentiometer or optical encoder.

While not just a chip on a board, these are hardly large devices. Barely 1.75" long (including pins) and 0.6" wide, they are very small compared to equivalent devices and the hard part of keeping the magnetics aligned in a neat package has already been done. I'm not sure why you are looking at encoders but you don't want something that acts like an optical encoder. Sounds kind of self defeating to me.

using quadrature position output neglects the one big advantage of magnetic encoders, which is that you can ask the sensor "where are you?" whenever you feel like it and get back a precise answer, without having to constantly monitor quadrature signals and keep track of where it is.

There are absolute versions of the encoder available that have a fixed frequency output and a dutycycle that represents position. It is a trivial task to measure dutycycle if your MCU has capture hardware. There are also many MCUs that have hardware quadrature interfaces which makes interfacing with an incremental encoder very easy too.

supposedly the as5046 works up to 10,000 rpm, so you'd have to sample at 4MHz for equivalent speed and resolution with a quadrature interface. (however it won't do both that speed and precision at the same time.)

Do you really need to know absolute position of a 10,000 rpm device? A hardware quadrature interface can easily handle an incremental encoder at that speed. If you don't have one, there is a Z-channel option which would allow you do keep track of full rotations until the connected device slows to a reasonable speed. The electroswitch parts are not designed for high speed systems (200 RPM max) mostly due to the bushing used.

the austria products also actually have datasheets, which are a plus.

Which is the reason I had to call electroswitch and ultimately introduced me to the Austrian Microsystems line of products.

-Bill

[eubarch]

On a related note, Austria Microsystems makes some linear magnetic encoders that are pretty neat. I could see where non-contact linear position sensing might be useful; like CNC mill conversion kits. I wasn't able to find a US distributor the last time I looked for them.

[ohararp]

I have used the AS5040 in a couple of projects and they work great. See a crummy iphone image for details. Unfortunately they won't let me post the .pdf of the schematic.

[kert]

Bump this one ? I found a madscientisthut.com breakout board for one 10-bit board here. Apparently these are also used in the newest Dynamixel servos.
Both RLS and Melexis ( MLX90316 ) also make a range of magnetic rotary sensors.

It would be really neat to have a few kits with boards on PCBs, magnets included, for a easy continuous servo modification. Small optical encoders tend to be pretty expensive.

[D9W]

HEck you could use the AS5048A/AS5048B for the weathervane sensor.

[kert]

More requests of the same
https://forum.sparkfun.com/viewtopic.php?f=5&t=26483
https://forum.sparkfun.com/viewtopic.php?f=5&t=16001

I am surprised that Arduino bot just came out without including a pretty basic feature like encoders.

[robertkyoski]

I have used the AS5040 in a couple of projects and they work great. See a crummy iphone image for details. Unfortunately they won't let me post the .pdf of the schematic.

Yes. I designed a simple evaluation board for the AS5040 rotary magnetic encoder so I could test it out for a few different applications. It works great!

[propjohn]

I can get the chips from DigiKey or Mouser, but neither of them carry diametrically polarized magnets: http://buyonline.arnoldmagnetics.com/p- ... agnet.aspx (must order in multiples of 25). SF's magnets are all axially polarized. Sure I can buy them from ams directly, but they tack on a $30 order processing charge

Better accuracy, naturally indexed, I2C or SPI interface, and can be daisy chained? Unless your application is magnetically sensitive, it sounds like a win over optical encoders.

Would love a breakout.

[madscientisthut]

We have the N35H 120C rated diametric sensor magnets for AS5035, AS5040, AS5043 and AS5045 in stock at $1.50 each

http://www.madscientisthut.com/Shopping ... %20Magnets

In the next few weeks we will be receiving N35EH 200C rated magnets.

Thank you Bill!

[propjohn]

We have ...

Found you guys the other day and placed an order for magnets and two of your populated 5040 boards