When to get new parts, and how to justify spending?

I am the coach of team 5263. Recently, we have been able to push our team to a more professional level after much support from our community after being around for 8 years. The team just purchased our first CNC router, 2 3D printers and upgraded our lab after 2 years of it being storage due to COVID. However, one thing I always struggle with is trying out the new and exciting while on a slightly limited budget. As much as I would like to give the students a chance to work with brushless motors and the new REV PDP, it is hard to justify when we have 8 years’ worth of kit of part CIM motors. Gearboxes get re-used and are finally wearing down to smooth gears, and spare parts we received from older teams make it hard to reason using new motors.

Despite all this, I still want to give the students a chance to use the latest and greatest to keep them on par with championship-winning teams (Sadly, no blue banners for us yet but we have had fun the whole 8 years!). What do more seasoned coaches recommend I do in order to get new parts for the student’s future robots? Another question, how and when do you do your shopping for gearboxes (Such as the sport series) without breaking the bank?

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I don’t have advice for the motor purchasing, but if you’re going to invest in a set of gearboxes I’d purchase a slew of VersaPlanetaries or MAXPlanetaries and just stick to one for most applications.

Personally I don’t think you’re missing out on much with the new REV PDP if you’re not currently limited by the CTRE components.

I’d definitely consider investing in brushless motors though, not just to keep up to trends for the sake of it, but because integrated sensors and more advanced programming are making life easier. You can choose to slowly make the transition as well. For example, keep your freshest CIM motors for one subsystem, but try brushless for another.

There is also value in waiting still given the issues tons of teams have when any new technology comes out. Being an early adopter is always a risk, and if you can’t swing the funds now, just wait and slowly make the transition.

If you have a CNC router, you can also start playing with the idea of simple custom gearboxes for some basic stuff.

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I recommend a 3-mentor approach, it’s worked well for us for the past 15 years. One to control the money, one to spend the money, and one to throw out the junk.

Our lead mentor, Sydney, controls the money. She does the budgeting, reimbursements, and keeps track of where we are as the season goes on.

I spend the money. Basically, I buy stuff throughout the season until I’m told to stop :slight_smile:

Another of our long-time mentors, Walt, hates clutter. So, he goes through the shop and adjoining areas once or twice a year and purges out the junk. Throwing old/worn out stuff out, cleaning the scrap bins, etc.

This approach means that, when we need stuff, it’s either something we already have that’s in good condition, or something that we buy new. It means we’re willing to spend the money for what we need, with appropriate speed bumps in place to make sure we don’t over-spend.

We don’t buy anything just because it’s new and exciting. We do, however, evaluate new products from the major FIRST suppliers as they’re released, and consider how they may impact future purchased depending on robot design. For example, in the past year everyone came out with telescoping tube climbing systems. Before kickoff, we had evaluated each of them and determined which one would best work with our design methodology - so when kickoff happened, I was able to place an order within a couple of hours and get the one we wanted before all of them went on backorder!

When it comes to motors, we’re almost entirely brushless now. Both the integrated sensors and the enhanced performance make them a clear choice over others. On this year’s robot, we have 6 Falcon’s (drive train and shooter), 2 Neo’s (climber, chosen over the Falcons for packaging reasons - the Falcon’s just wouldn’t fit), 2 Neo 550’s, 1 Redline (we didn’t need any sensors here, so why bother spending the money on a new motor when this one works fine) and 1 Bosch seat motor (perfect packaging and speed for what we need).

We’re also heavily invested in the Versaplanetary system. That means we buy some new stuff each year, but we also have perfectly fine used components sitting in the shop that we can use as well. It all depends on what gear ratio’s we need each year, and what we have available.

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Be very strategic about shipping. A team can easily blow through hundreds of dollars in shipping costs if they’re not careful. Vendors offer various deals on shipping – if you pay attention to those deals, you can save a lot. And, there’s nothing wrong with combining orders with other teams.

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I am very happy with the Versaplanetary 100:1 on a bag motor we have had for around 6 years now. It has been used all but one season, but until recently spending $100 on one part hasn’t been an option. I know the falcons are pricier, but with the Neo 550s, are they easy to work with as compared to the falcon?

Where do you recommend getting gears to make the gearboxes? I looked at a few websites, but it seems making a gearbox would be just as expensive given the price of gears off Andymark and sites related. I am hoping the students can play around with making gearboxes during the off season for practice.

If your goal is to have kids just learn how to build gearboxes, there’s no harm in taking models of gears from AM, VEX, WCP, McMaster, Boston gear, etc and printing them for kids. Once you decide on a speed you want to produce, then purchase the gears. Polycarb routered or 3D printed plates work fine for teaching.

For the brushless motors, there’s not a huge difference between the Falcon 500 and the NEO+Spark Max. The NEO 550 (+Spark Max), however, is quite different, as it’s designed as a replacement for a 500-series motor instead of a CIM replacement. So, it’s much smaller, much faster, and must less torque than a Falcon. Great for some scenarios, not great for others.

The major differences between the Falcon and the NEO line are:

  • Motor controller. The motor controller is integrated with the Falcon, while the NEO needs to be attached to a Spark Max. Note that both the NEO and NEO 550 have an encoder cable that have to be hooked up to the Spark Max, in addition to the 3 power wires.
  • API’s. The Falcon uses an integrated Talon motor controller, so if you’re familiar with the CTRE API’s for the talon, it’ll all be very familiar. The Spark Max has a completely different set of API’s, and there are some feature differences between the two.
  • Size. The Falcon is a little longer than the NEO, due to the integrated motor controller. This can have packaging implications in tight spaces, but in many cases it doesn’t matter.
  • Output Shaft. The NEO has a keyed shaft, the same as a CIM (Makes it very easy to swap from CIMs!). The Falcon comes with a removeable spline shaft. This lets you change the shaft if you want (there are keyed shafts available, as well as short spline shafts designed to use with the Versaplanetary, so you don’t need to cut the shaft to fit). Note: See other threads on here about the quality control issues that have happened with the Falcon’s as a result of this replaceable shaft.
  • Casing. The NEO 550 is an outrunner (the only outrunner currently available in FRC), so the outside of the motor actually spins with the shaft - the only part that doesn’t spin is the front plate used for mounting.

If you have a lot of kit of parts chassis I would suggest opting out of the chassis next year. You will get a credit with AndyMark ($450.00 this year). This could be a good way for you to get a variety of components.

VEX PRO has rewards program. They give you a $50.00 credit when you sign up. Then you get free shipping on Mondays.

One thing to keep in mind on the brushless motors: durability. They are such an enormous improvement you want them as soon as you can afford them!

We bought NEOs pretty early and have quite an inventory of them. HOWEVER, unlike many top teams we re-use them. So, we have motors with YEARS of running and abuse on them. Abuse all the way to “there’s only half an inch of encoder cable bundle sticking out of this motor!” level. I’ve currently got 7 NEOs on my workbench waiting for long JST-PH cables to re- cable them. In addition to the one where the kids let out the magic smoke :boom: I’m expecting that fresh encoder cables will save most of them. All of that fun has led to my working on a full-boogie NEO tester board.

I’m hoping that the Falcon’s will solve the vulnerable cable challenge, but they seem to have their own challenge with screws and screw retention.

So, be aware that some FRC components are being run right out to the hairy edge of their performance envelope and may only last a few seasons! And some of them are just bomb-proof and last forever…

I want to hear a bit more about this. The length of the encoder cables is a nuisance for our team – REV sells 3-foot extensions, but what do you do if you only need one foot? We bought a crimper for the JST-PH connectors and some ribbon cable, but that wasn’t very successful.

What are you doing? Why are your cables so short?

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Ummmm… smashing them between motor cans and climb components :scream: has been shown to reduce cable lengths abruptly.

There’s also quite a range of less catastrophic damage and wear…

If you want about a 6" extension there’s a kit on Amazon that lets you assemble JST-PH extensions of a range of pin counts. Very handy, and also handy for repairs. Well crimped wires!

PH 2.0 Connector Pre-Crimped… https://www.amazon.com/dp/B08T89ZK2Q?ref=ppx_pop_mob_ap_share

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Regarding neos and spark maxs:
There’s always been bugs in the rev API, usually regarding functions that could be programmed through the rev hardware client. Others are not too happy about the 42 cpr encoders on the neos and 112ms of delay caused by non configurable filtering on the spark maxs.

The ability to plug in to and control motors (and now pdh and pneumatics hub) over USB has been incredibly useful for testing and tuning pid.

I haven’t used falcons myself however I have heard very good things from other programmers using them and would rather use them than neos where possible as they have better encoders (1024 cpr), don’t have an encoder cable to accidentally slice, and from what I’ve heard, aren’t known to have buggy apis.

But they’ve got a can wire to slice

My advice: protect your cables so that there’s not even a chance for them to get sliced

Regarding falcons:
This year they have a tendency to blow themselves up or tear themselves to bits due to issues with loctite and other mechanical things. But that’s mechanical’s problem not mine :wink:

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We’ve found the jst ph connectors to give up without cable getting sliced. The wires all look fine but when plugged in one of the encoder phases doesn’t make contact so the motor will either act like it works and fail under load or will just not work until we cut and solder on a new jst tail

We didn’t have much luck crimping JST-PHs either, so I just bought this kit https://www.amazon.com/Connector-Pre-Crimped-Compatible-JST-PH2-0mm-Inductrix/dp/B08S32GJRF and soldered the pre-crimped ends on. If you have early NEOs with the smaller gauge encoder wire, this is a great solution because the connector becomes more robust by having a heavier gauge wire crimped into the connector.
In theory, if you’re ok with having multiple solder splices you could do this and then extend these as much as you need. We turned a bunch of 36" 6 pin extenders into 72" and 96" extenders by soldering them together (there’s probably a more efficient way to do that, but we had a bunch of REV 36" extenders around), removing the need for the jumper board.

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If you wanted to try and split up the cost of things, my team bought spark MAXes this year and is going to be getting NEOs in future years. The sparks can work with brushed motors as long as you tell it what style motor it’s controlling.

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Our electrical/programming students really enjoyed the spark MAXes we got this year, and we aren’t running brushless. Hoping to add some NEOs to our arsenal after another round of fundraising. Did your team test Dyanmo motors, the $50 ones on Andymark with built-in controller? I keep looking at them but at our first competition, didn’t really see many in use.