Endless absolute encoders (and Hello!)

Hi there!

I am quite the noob here and hoping someone can give me a bit of a helping hand! I'm looking for an knob that can be turned endlessly whilst continuously providing the absolute position of the knob. Ideally with a relatively high degree of sensitivity (1024 values?).

If anyone could point me towards any appropriate encoders or advice that'd be great! I'm looking to interface with an Arduni Uno board (is a different one necessary). I also want to have quite a large encoder (though this could just be built on top of small encoder) to measure the angle of fairly wide pole that will be twisted so perhaps robustness is a factor?

Any encoder/arduino pros want to give me some helpful advice?

Thanks!

Crabhands

Here is an 8 bit one (256 steps) that is not too expensive. http://uk.farnell.com/bourns/eaw0j-b24-ae0128l/encoder-rotary/dp/9358234

Here is one with the same resolution that is too expensive:- http://uk.farnell.com/omron-industrial-automation/e6cp-ag5c-c/encoder-absolute/dp/474540

Thanks for the reply Mike :)

Do you have any similar suggestions for something with more than 360 values as I'd like to ensure at least 1 value per 1 degree. I'm not certain if this sensitivity will be 100% necessary or noticeable but if the difference in cost isn't much more I figure why not! XD

Crabhands

if the difference in cost isn't much more I figure why not!

Going above 8 bits will move the decimal point in the price one or two places to the left.

9 bits:- http://uk.rs-online.com/web/p/rotary-encoders/4997554/

This is an alternative:- http://www.austriamicrosystems.com/Products/Magnetic-Encoders/Rotary-Encoders/AS5040

Grumpy_Mike:

if the difference in cost isn't much more I figure why not!

Going above 8 bits will move the decimal point in the price one or two places to the left.

Money must work different in good old England. Here you move the decimal point right to increase the costs. ;)

Hey left / right much the same to a dyslexic, until I have to pay I suppose. :)

Thanks for you next set of suggestions Grumpy Mike!

The price jump is massive! As far as I can tell the price for the austriamicrosystems encoder is £12 which isn't in keeping with the price of the other one. Am I reading this wrong or were you kind enough to provide me with the perfect alternative to the £400 one!?

Well the AS5040 is quite cheap and gives you 10 bits resolution, but it is only half the solution. It is a chip that senses the direction of a magnet. Therefore you have to come up with the mechanical construction yourself. This may or may not be suitable for your project.

The other 9 bit one is an optical design, very reliable but expensive because of the high precision optical encoding disks and emitters and sensors. Finally the first 8 bit one is a mechanical contact one, less reliable but still remarkably cheap compared to what they used to cost.