Encoders for 2015 Season

[Joey Milia]

Originally Posted by mman1506

I can't stand the tiny little connectors on us digital encoders, they always broke on us. I much prefer the solder terminals on other encoders like greyhills.

Originally Posted by Jared

My favorite encoders are the greyhill ones. They're more expensive and a tiny bit larger, but they are quite strong.

Originally Posted by AdamHeard

I'm a big fan of US Digital, and use the super high count E6's where it makes sense... but for a shaft based option I'm not seeing the advantage of the H6 over the grayhill encoders. Much more money and size!

Which grayhill model do you use and where do you source them?

[mman1506]

Originally Posted by Joey Milia

Which grayhill model do you use and where do you source them?

The grayhill 61K, 61E, 63R are the series commonly used in frc. They can be purchased from digikey.

[nathannfm]

Are there any good options for measuring off the back shaft of a banebots style motor? Mainly common FRC encoders than can do 20,000 RPM and if there are any known good mounting options/tricks.

[AdamHeard]

Originally Posted by nathannfm

Are there any good options for measuring off the back shaft of a banebots style motor? Mainly common FRC encoders than can do 20,000 RPM and if there are any known good mounting options/tricks.

By the time you have any meaningful reduction off it the precision will be poor due to backlash for average FRC gearing. This could be acceptable for the application or a huge pain.

[nathannfm]

Originally Posted by AdamHeard

By the time you have any meaningful reduction off it the precision will be poor due to backlash for average FRC gearing. This could be acceptable for the application or a huge pain.

Right, thanks for pointing that out, so no good for 100:1 VP on a swerve drive. We tried reading a shoulder bolt sticking out of the tapped hole but the tolerance on on that hole is non existent and it wobbled all over the place. Guess we are going to have to press a pin in and turn it to round after its in the shaft.

[Qbot2640]

Originally Posted by mman1506

The grayhill 61K, 61E, 63R are the series commonly used in frc. They can be purchased from digikey.

Excuse my lack of experience - we have never used encoders, and I desperately want to this year. The Grayhill models referenced above look like potentiometers, for lack of a better description...How are they installed? Do you just couple the shaft to the gearbox shaft?

I understand how the US Digital one's install - in fact, we installed a pair on our robot this fall for the off-season, but never figured out how to wire them up or program them.

[Jared]

Originally Posted by Qbot2640

Excuse my lack of experience - we have never used encoders, and I desperately want to this year. The Grayhill models referenced above look like potentiometers, for lack of a better description...How are they installed? Do you just couple the shaft to the gearbox shaft?

I understand how the US Digital one's install - in fact, we installed a pair on our robot this fall for the off-season, but never figured out how to wire them up or program them.

They're installed just like potentiometers, but they have no restriction on how far they can turn. If you want, you can couple them to a gearbox shaft, or you could put a sprocket or pulley on the encoder shaft.

To couple the shaft of the encoder to the gearbox without having to buy/make a shaft coupler, you can actually use a short piece of surgical tubing, and stick the two shafts inside the hole in the middle of the tubing and put on a few zip ties to prevent it from sliding out.

[mman1506]

Originally Posted by Qbot2640

Excuse my lack of experience - we have never used encoders, and I desperately want to this year. The Grayhill models referenced above look like potentiometers, for lack of a better description...How are they installed? Do you just couple the shaft to the gearbox shaft?

I understand how the US Digital one's install - in fact, we installed a pair on our robot this fall for the off-season, but never figured out how to wire them up or program them.

You are correct, they interface mechanically exactly like a pot would. Here is a pic of two grayhills 971 has on their bot https://lh6.googleusercontent.com/-f...52841%2529.JPG .
What's really great about the greyhills is that the shaft is supported by a ball bearing so they are MUCH more tolerable tolerable to axial and radial load than the commonly used US digital encoders.

[Ether]

Originally Posted by mman1506

What's really great about the greyhills is that the shaft is supported by a ball bearing so they are MUCH more tolerable tolerable to axial and radial load than the commonly used US digital encoders.

Two things:

1) It's spelled "Grayhill", with an "a". (It's easier to find if spelled correctly)

2) Not all models of Grayhill encoders have ball bearings. Make sure to check the datasheet before ordering.

[mman1506]

Originally Posted by Ether

Two things:

1) It's spelled "Grayhill", with an "a". (It's easier to find if spelled correctly)

2) Not all models of Grayhill encoders have ball bearings. Make sure to check the datasheet before ordering.

All of the models I previously listed and referenced to in my post are ball bearing supported.

[Ether]

Originally Posted by mman1506

All of the models I previously listed and referenced to in my post are ball bearing supported.

I should have been clearer: The caution clarification was for other readers.

The specific post I responded to had no list and no reference.

[AdamHeard]

Originally Posted by mman1506

You are correct, they interface mechanically exactly like a pot would. Here is a pic of two grayhills 971 has on their bot https://lh6.googleusercontent.com/-f...52841%2529.JPG .
What's really great about the greyhills is that the shaft is supported by a ball bearing so they are MUCH more tolerable tolerable to axial and radial load than the commonly used US digital encoders.

Us digital does have shaft based encoders as well.

[Sh1ine]

Originally Posted by Qbot2640

Excuse my lack of experience - we have never used encoders, and I desperately want to this year. The Grayhill models referenced above look like potentiometers, for lack of a better description...How are they installed? Do you just couple the shaft to the gearbox shaft?

I understand how the US Digital one's install - in fact, we installed a pair on our robot this fall for the off-season, but never figured out how to wire them up or program them.

We use Grayhill Encoder 63R128 (http://www.digikey.com/product-detai...3069-ND/304478) They are terrific encoder, and Digi key sells them at a good price. We use 128 count encoders for our drive train, and since we have them laying around, they get used for other systems frequently as well. In order to to attach our encoder to our output shaft we use 1/4 OD and 3/16 ID surgical tubing. It sounds sketchy, but works great, it also helps absorb some slight misalignment issues that you might have. Simply slip the tubing over the .250 part of a AM output shaft and the other side slips onto the encoder. Create a bracket to hold it in place and you are good to go.

Here is an image:

https://drive.google.com/file/d/0B02...ew?usp=sharing

Hope this helps!