Encoders for 1/2" Output Shaft

[Ginger Power]

I'm wondering if anybody knows of non-optical encoders that can be mounted on a Gem 500 output shaft which is 1/2" in diameter?

[Knufire]

I belive the end of the shaft is tapped for 1/4-20, correct? You could try sitcking a 1/4-20 bolt in the end with a shoulder and running many of the 1/4" through-shaft encoders on the bolt.

[Ginger Power]

Originally Posted by Knufire

I belive the end of the shaft is tapped for 1/4-20, correct? You could try sitcking a 1/4-20 bolt in the end with a shoulder and running many of the 1/4" through-shaft encoders on the bolt.

That's an awesome idea except the way we currently have things set up we would have to route the wires around a wheel that we are direct driving.

[asid61]

I've been looking for one as well, perhaps for use on hex shaft.
So far I've found that the easiest thing to do is to put one earlier in the drivetrain, such as on the face of the CIMs, the gearbox shafts, or the ends of shafts.

EDIT: Why non-optical?

[Gdeaver]

http://www.chiefdelphi.com/media/papers/3165
Our team is working on using this encoder on our swerve.

[GeeTwo]

It may not be the neatest solution, but you could use a 1/2" to 1/4" shaft coupler and a short length of 1/4" shaft/bolt.

A bit neater would be to machine (mostly lathe work) a bit of 3/4" shaft to have a 1/2" hole with set screw on one side and a 1/4" (or other useful size) shaft on the other.

And unless you can find an encoder that will do this, the neatest of all is to machine the 1/2" shaft down to the appropriate size, though it would have to be done during build season assuming the fabrication schedule and rules are similar to recent years.

If you only need a few counts per revolution of the shaft, you could paint the shaft with black and white stripes and use a reflective counter.

[Ginger Power]

Originally Posted by asid61

I've been looking for one as well, perhaps for use on hex shaft.
So far I've found that the easiest thing to do is to put one earlier in the drivetrain, such as on the face of the CIMs, the gearbox shafts, or the ends of shafts.

EDIT: Why non-optical?

Mounting the encoder directly on the cim output shaft was our first solution, but if you aren't familiar the the Gem 500 gearbox, the way the cim is mounted makes it hard/impossible to effectively space it out to fit the encoder in. I'd also be worried about spacing out the motor because I'm not sure how the shaft would react with the gear at very end of it at stall torque.

The logic behind avoiding optical is that this is for the NASA Robotic Mining Competition and it gets very dusty when mining. So we would be penalized for lack of dust tolerance as well as possibly having problems with the encoders in dusty conditions.

[AdamHeard]

Embedding a quadrature output magnetic gear tooth sensor like 2363 (and 3847) did with a versaplanet might be an option.

http://www.chiefdelphi.com/media/papers/3165

Or give up some shaft length and do it entirely external on the shaft close to the output bearing.

[asid61]

Originally Posted by AdamHeard

Embedding a quadrature output magnetic gear tooth sensor like 2363 (and 3847) did with a versaplanet might be an option.

http://www.chiefdelphi.com/media/papers/3165

Or give up some shaft length and do it entirely external on the shaft close to the output bearing.

You might be able to modify the GEM in a similar manner, or attach a gear to the output shaft and use a similar mod.

[Gdeaver]

Take a few minutes and read that paper, then download the data sheet. This sensor packs allot in a small package and can solve the tough quadrature encoder apps. We have the sensors and will be implementing them on our swerve drive. 8.00$ plus shipping, some caps and resistors and cable.

[Ginger Power]

Originally Posted by AdamHeard

Embedding a quadrature output magnetic gear tooth sensor like 2363 (and 3847) did with a versaplanet might be an option.

http://www.chiefdelphi.com/media/papers/3165

Or give up some shaft length and do it entirely external on the shaft close to the output bearing.

Wow this is a crazy awesome solution! Thanks Adam!