We are currently investigating different types of encoders for our team to use after our encoders’ optical disc cracked. Here are some things we are looking for:
What encoders is your FRC team using?
Was there any setup/configuration needed in your code to have them properly work?
How were they wired to your roboRIO?
Also, because we are trying to purchase encoders in the middle of competition season we have not been able to find a whole lot of options since Andymark is sold out. If you have some good references, it would be much appreciated!
For our drivebase we’re using CTRE Magnetic Encoders in relative mode hooked up to a breakout board for the Talon SRX. We’ve had a lot of success with these thus far, but did have one small failure that was mostly due to some naive wiring. This has been the easiest encoder I’ve worked with so far, as long as the shaft you’re working with already has a magnetic end. It’s annoying to pocket the shaft otherwise, but not too difficult.
For our elevator we’re using the RS7 Encoder, which I’d highly recommend if you’re using a Redline/775 Pro. It’s taken quite a bit of abuse so far and still is working fine (besides when the wire severed… but that’s no fault of the encoder). This again is wired to a breakout board for a Talon SRX.
Neither of these took a lot of extra effort to set up, and most major FRC encoders won’t either. I’d highly recommend Talon SRXs if you’re looking to use more advanced control systems in the future, but you should be able to wire both of these to a RoboRIO fairly painlessly if you read their User’s Manuals.
To use them, it’s usually simply using the Encoder() class of WPI-Lib, although more recently we’ve wired them directly to the Talon SRX and used them that way.
So this was our first year using encoders, and we used VEX quad encoders from our classroom kits. We built custom wires to connect them to the SRXs and they work pretty good on the drive train. Definitely not the best solution, but it was one we could implement.
This year its the CTR magnetic encoders for the drive - we are also using EVO 2 speed shifters that come with a magnetic shaft. We ribbon cable directly to the Talon SRX controller.
I’d love to hear how folks mechanically connect the magnetic encoders - its probably just me but I have a heck of a time getting them aligned just right on the magnetic shaft to stay “green.”
For our elevator encoder, we are using a US-digital E4T optical encoder, connected via break out box to another Talon SRX controller.
Would have to ask our SW folks exactly how we are using these encoders…
Yellow works for us too.
When we use the magnetic shaft on the EVO shifter, that shaft sticks out at least an inch from the shifter body…so we attach a plastic bracket (the one used with the E4T encoder) then use a rubber ring to sit the Mag encoder on so we can get some wiggle room for slight height and centering adjustments.
It’s more of an art than a science to get a green LED…
We’re using CIMcoders for the second year in a row, and they work great – though I highly, highly recommend not only loctite on the set screw, but supergluing the magnetic disk in place on the shaft. (Then remove the spacer, then finish assembly.)
It’s hard to overstate how much I loath set screws…
Well I’m not who you asked but this is our 4th year using the CUI AMT 10 series encoder for 4 years and it is far and away the best encoder for FRC use. You can select the ppr to suit your application. They are so reliable we are still using a set on our practice robot from 4 seasons ago. The shaft adapters and mounting brackets can break but they are cheap and available separately.
The bases of the mounting brackets are equipped with many different bolt patterns but we have always mounted them with the KOP 3M tape.
We also bought a bunch of CTRE/SRX mag encoders and magnetic shafts this year. We’ve had too many E4T discs destroyed by gorillas taking the gearbox apart without even trying to save them. We’ve been wiring encoders to SRX controllers for a couple of years now; a bit less expensive now that we can put the second drive motors in follower on an SPX.
We are using the CTRE Mag encoders, and 3D printing the mounting spacers using the STL file provided on AndyMark’s website. We use the Talon SRX data cable for plug-and-play functionality. This is the easiest time we’ve ever had setting up an encoder.
The only thing we wish we could do is plug into some kind of breakout board for the Talon SRX that would accept the 10-wire data connector from the encoder AND allow some kind of interface to a limit switch, so we could put hard limits on our lift. I bet it’s possible if we splice out the tiny 10-wire ribbon cable, but that’ll be a project for next year rather than trying to hack it into our competition robot.