Rotary encoders vs. price
 

I'm having trouble reconciling what differentiates popular FRC rotary encoders, especially since their price varies so much. For example, based on DigiKey:

• AS5145B Quadrature Magnetic Encoder; $38; 0.0879deg resolution
• Grayhill 63R Quadrature Optical Encoder; $54-$75; 64PPR encoder more expensive than 256PPR encoder?
• TT 6120 Hall Effect (Absolute?) Encoder; $15; 0.088deg resolution
• CUI AMT203-V Absolute Encoder; $49; 0.2deg resolution

I know max RPM and mechanical life varies between each encoder, but what else accounts for each sensor's price difference/popularity?

Re: Rotary encoders vs. price
 

Another good option is CUI's AMT-102V. It's $24, has up to 2048 counts per revolution and is easy to mount. We used them extensively in the 2015 season and expect to continue in 2016.

Re: Rotary encoders vs. price
 

The Grayhill encoders have internal bearings, which increases the cost.

Re: Rotary encoders vs. price
 

Grayhills are also sealed and require no assembly (read: stupid-proof). This is why we use them.

Re: Rotary encoders vs. price
 

Re stupid-proof - no such thing; rather say "stupid resistant" :)

Re: Rotary encoders vs. price
 

AS5145B - low RPM, magnet must be positioned very precisely

TT 6120 -- haven't looked at this before -- isn't it a position sensor, not an encoder?

Re: Rotary encoders vs. price
 

Some more options...

CTRE Magnetic Encoder (absolute within one rotation and relative - we make this one)
These are unique in that it uses the same cabling as Talon SRX, so they plug right into the Talon.
http://www.ctr-electronics.com/srx-m...c-encoder.html

If you are using Versa, there is a slice with same CTRE sensor built in.
http://www.vexrobotics.com/vexpro/al.../217-5046.html

Another analog encoder (MA3 US digital) I've used and seen teams use (absolute within one rotation)
http://www.usdigital.com/products/en...tary/shaft/ma3
Another popular quadrature encoder(relative - us digital) I've used and seen teams use.
http://www.usdigital.com/products/e4p

Re: Rotary encoders vs. price
 

Alot of the popularity comes from how easy they are to mount. For example the greyhills yoy can easily zip tie down the wire and attach to a shaft via surgical tubing (so I hear). To some teams that justify the price. I perfer the CUI ATM-102V encoders because of the price, that said they are a pain to mount, but for my team that is a sacrifice we are willing to make.

Re: Rotary encoders vs. price
 

Also the US Digital S4T, which is essentially the shafted version of the E4P.