SparkFun Electronics - Rotary Encoder

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Rotary Encoder

sku: COM-09117

Description: This is a 12-step rotary encoder with a nice 'clicking' feel. It's breadboard friendly, and has a pretty handy select switch (by pushing in on the knob). The encoder is different from a potentiometer in that an encoder has full rotation without limits. The unit outputs gray code so that you can tell how much and in which direction the encoder has been turned.

This unit does not come with a knob, but a working knob is related below.

Documents:

Datasheet
Rotary Encoder Tutorial and Arduino Project. Thanks Oleg!
Example Arduino Project. Thanks Steve!
Example Cooking Timer

Pricing

	1212 in stock backorder allowed

$2.95	price
$2.66	10-99 (10% off)
$2.36	100+ (20% off)

	quantity

click on image to enlarge

Comments

14 comments

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	by nukwaste +3.2 \| Mar 3, 2009 at 9:11am 0
The Rotary Encoder sku: COM-09117 is missing its PDF data sheet. http://www.sparkfun.com/datasheets/Components/TW-700198.pdf fails.

	by skelso +1 \| Mar 3, 2009 at 9:12pm 0
Wouldn't most say this is a quadrature encoder? Gray code implies absolute, and this would need four bits of Gray to be that. Yes, quadrature is a two-bit Gray code, but still...

noworries

+6.2

| Mar 4, 2009 at 1:07pm

Yes, I agree with skelso that quadrature would have been more descriptive. The datasheet also does not fully describe which pins the push switch connects to, but I assume that they are the two unlabeled pins. I also assume that they meant to describe the switch as a momentary, normally open type which goes to closed when the shaft is pressed down.

Clarity in datasheets is becoming rare nowadays...

	by galaxip +1.5 \| Oct 5, 2009 at 8:10pm 0
I have the push working nicely. But cannot make sense of the rotary encoding. The values the device reports seem very arbitrary. It is frustrating; I am going to need to re-think the interface to this project. If I had been able to make this work as expected it would have been a perfect choice for this control interface.

	by UndefinedExpression +2.5 \| Oct 14, 2009 at 8:22pm 0
Take a look at this, it may be relevant to your interests: http://en.wikipedia.org/wiki/Rotary_encoder#Incremental_rotary_encoder

	by cuzincuz +2 \| Nov 22, 2009 at 9:37am +0.16
hi - so i am using the 3 pins on one side to read-in the rotary data no problem. and actually there is little to no bounce, which is uncommon for such a cheap little unit! but also i have a question, i can't figure out how to read in the push button data ... it doesn't seem to be the two pins on the other side ... am i missing something?

	by medecau +1.9 \| Jan 6, 2010 at 7:41am +0.15
I have the some example code for the Arduino that does a decent job figuring out where and how much is being turned on the encoder. Take a look here: http://gist.github.com/154809 (if you can help improve the code please fork it)