Thoughts on NEOs and Spark Max

Now that everyone’s had a couple of seasons to break in REV’s new brushless infrastructure, what do you all think about NEOs and Spark Max’s? Do you like the integrated encoders on the NEOs? How do the features of Spark Max’s compare to Talons? We are considering using NEOs + Spark Max’s for our mecanum drivetrain this year (partially due to the integrated encoders which we would need for PID); would you recommend them over CIMs + Talons?

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Yes. The brushless motors are much better in every regard. Highly recommended.

That said, if you have a bunch of cims around and not a lot of money to spare - get the robot built with what you have.

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If you’re already using Talons, then why change things on you’re programmers? If you want to switch to brushless motors, get Falcons. They have features at least as good as the Neo/SparkMax combo but use the CTRE features that you already know from using Talons (especially if you’ve been using Talon SRX controllers and all their features.) The built-in encoders will do the job for your mecanum drive, plus you have the controllers built-in too, which makes the whole thing easier to manage.

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Availability of Falcon’s this season (I can get NEO’s and Spark’s overnighted to us right now), along with the recent price hike would be two reasons off the top of my head I can think of that may cause a team to consider switching ecosystems/vendors. There was also 2 spark MAX’s in the KOP this year, helping reduce the overall costs again.

I fully agree keeping things the same (or very similar) for programmers is nice, but I would value being able to have an extra 2+ weeks with equipment in hand and saving potentially a couple hundred dollars (or more), over keeping programmers feeling comfortable.

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If you’re going to use Spark Max’s and NEO’s, then make sure you also buy JST connectors, pins, and a crimper. Make sure your pit crew knows how to use them.

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Our team is in a similar position to @Indigo2003 and I fully agree that the reasons to switch you listed are very valid (availability of Falcons this season, price hike vs “free” Sparks, etc).

However, you might be grossly underestimating the work needed to quickly port an existing code based from CTRE to DEV considering the abysmal level of software documentation provided by REV at this time.

See REV Software Reference Manual? - Technical / Java - Chief Delphi for my thoughts on the matter.

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We used Neos on our mecanum bot last year. We love them when they work. Rev made an incredible device. Depending on what you want to do, they will work well for you.

A few caveats you should keep in mind though.

  1. Be incredibly mindful of the wiring. Use cable connectors that lock for all 3 power/phase cables and make certain they are away from moving parts (and facing up since they cannot get snagged on the floor).

  2. Do the same with the data cables.

  3. Know that without all of the cables (3 power/phase and data) connected securely, the motors are unpredictable (they may still work, but not as you expect).

4) Buy a few extra motors and be prepared to swap them during an event in case a cable gets severed. We have replaced the JST cables on a motor twice. I would not be able to do it during an event. Most of our members cannot do it at all. It is finicky. See the post @nuclearnerd placed below for a better solution.

One learning curve in the translation of code may be units and resolution. I do not think the Neo’s built in encoder has the same resolution (or frame rate) as an external encoder. This was not an issue for us, but we did not do trajectories or anything with them.

Gearing on a mecanum bot is inportant. We were happy with ours, and that may play a role in how a neo works for you compared to a cim. I am not really sure how much it will affect you, but it could be a thing.

FYI these IDC JST connectors will work in the Spark Max’s and are a great option for a field repair of a broken Neo signal cable: 06KR-6H-P JST Sales America Inc. | Connectors, Interconnects | DigiKey

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That is incredible. I did not know it was a thing and will save a bit of headache moving forward. How do you use them?

Hey. I am under the impression, based on your post in the other thread I linked to, that you are planning to use CTRE controllers this season. Am I mistaken, and if not, why the switch from REV to CTRE then? Thanks.

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They’re “IDC” (insulation displacement) connectors, so you just have to push the wires into the slots with the right size flat head screwdriver. It’s maybe not as strong as the crimps, but a heck of a lot easier to replace in a pinch.

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Yes. We have switched to Falcons for our drivetrain. We still use Neos (and the 550s), but we had some issues with cables getting snagged. There were many design flaws that played a part, but we were able to avoid the issue altogether by eliminating the data and phase cables.

Last year’s game was pretty brutal on exposed cables, but we did have some issues with cables coming undone. We also, just last night, reworked our current drivetrain to ensure all cavles are facing up.

TBH if it were up to me, and if it was between Neos or Cim and Falcons were not an option, I would choose Neos. But I would devote extra time to ensure the cable runs were perfect.

The Falcons were an option for us this year, so we grabbed them.

We just utilized the “email us when they are in stock” button and then purchased a few when we got the in stock notice.

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Thank you for sharing your experience.

We have a tough decision to make: we can hope to snatch Falcons at the last minutes, go “back” to Talons + CIMs, or try porting our code to the Sparks + Neos.

My main concern is that we have only a few pretty junior students in the programming team this year and that the school’s quarantine/isolation protocols may reduce the number of people that can physically access the robot, which is needed to program it without proper software documentation…

I certainly wish we had ordered Falcons upfront for this season…

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Overall, the NEO and NEO550 are both great (and cheap!) brushless motors. The Spark Max, on the other hand, still needs some work (in particular the velocity measurement delay renders the onboard encoder useless for velocity control of anything with characteristic timescales shorter than a few hundred milliseconds).

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That makes a lot of sense. So the neos worked well for your mecanum drivetrain? Someone else on the thread mentioned that there is some lag in the encoder response. Thanks for the heads up about the data cables though, and thanks @nuclearnerd for that solution. Also, did you find power pole connectors sufficient for the rest of the wiring?

I’m not too worried about porting code over. I’m our lead programmer and we aren’t too invested in CTRE infrastructure. The REV code examples seem sufficient and fairly straight forward.

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Just gonna leave this here for OP.

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In 2019 my team switched to NEOs and Spark Max’s due to weight issues. They did provide us with a massive leg up but we have had some issues.

  1. When we first got them we had issues with 1 of our spark maxes randomly reverting to older firmware. This was fixed in a later update and has not happened again since.
  2. We have had a lot of spark maxes randomly dying. They would connect to the spark max client but would no longer respond to control inputs from anywhere. This caused us a great deal of instability. It is quite possible that we got a bad batch and that these issues are now non-existent, but this led us to switching to falcons for the 2021 season, but I understand supply is an issue.
  3. We have had lots of encoder issues which we concerned us, as even thought we had the capability to fix these quickly, this does not help if the encoder cable fails during a match.
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Along with being disrespectful, this is completely unnecessary.

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There you go on the availability question. We bought 8 Falcons just over a week ago from Vex when they came back in stock. We’re using all of them for our swerve drive this year. We have more for other applications (shooter, climber) so we’ll be using a lot of them this year. But the thing to do is to sign up for the notifications from everyone who carries them and be ready when they are available.
I’ll also note that this tells you something about how popular Falcons are, that they keep selling out.

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Thanks! Just to clarify though, we aren’t really considering purchasing falcons just because of cost and shipping. It’s mostly a choice between either NEOs + Spark Maxes or CIMs + Talons since we already have them. Encoders seem like they’ll be a necessity since we’re running a mecanum drive this year, plus the extra power from the neos will help makeup the losses due to the mecanum wheels.

Would it be better to just stick with cims and talons and mount SRX mag encoders on the drivetrain?