My team has always bought new electrical components for our competition bot each year, with the rationale being that the old components are too likely to fail. How necessary is this practice, especially with passive components like PDPs? On of our coaches and I are working on getting an order placed, and we were wondering if we really need to spend $435 on a RoboRio and $205 on a PDP when we already have extras of both.
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I would say it depends on how many robots you’re trying to keep operational. Add 1 to that number. If you’ve had a failure, replace it. If the first number is 1, add 1 again…
I’ve seen one PDP failure, and it was an odd one after two years of use. Other 2±year old ones are still operations.
If you abuse them, they can go bad. Do you protect the electronics from metal shavings? and use care with all connectors, cable strain relief, etc?
We have 3 sets of electronics, only because we seem to need that many to develop things concurrently. We don’t really keep track of how old or new they are. We do try to bring spares with us to competitions. The only failure I remember in recent history was obviously caused by metal shavings, due to careless work on our part.
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We keep a minimum of 3 sets of “core” electrical components, namely RIO, VRM, PCM, Radio, PDP and RSL. This leaves us with enough for a competition bot, a prototype bot, and a testing board for programmers. This number can easily change depending on your constraints, but the only reason I see for having more than 3 sets is if you are keeping old robots together.
For motor controllers, we usually attempt to have 1.5 to 2 full sets of whatever we want on the bot, and use the remaining controllers for the prototype and test boards.
As to broken or issue components, the only time we’ve had issues in the past 7 years has been when a new electrical student wired the input to the PDP backwards, and ended up frying the PDP, VRM, and a few Talon SRXs (the RIO and bridge needed to be recovered manually, but we did get them working after the season).
As of fall 2018 season when I left the team, 3946 had four sets of electrical components to support a competition, practice, demo, and testing, but was still using all of the main electrical components from the 2015 KoP and a second set purchased that year except one PCM which failed in summer 2015 IIRC. I suspect the failed PCM had been powered in reverse. We’d put new motors on the competition robot, but other than that, unless an electrical device had shown issues or the battery dropped below good on the battery beak, it was fair game to go on the competition robot.
It depends entirely on your use case. If you have 0 need for your 2020 bot after 2021 kickoff, there are many teams that still use their original control system from the 2015 KOP.
2191 has made an effort to keep every bot from 2015 on operational (excluding 2016), so we’ve been buying roboRIOs for a few years now (we’ve been fortunate enough to get the rest from FIRST Choice every year).
You mentioned you have extras - it’s worth noting the current control system is only guaranteed to be used through 2021 at this point in time. If you have enough for next season, stockpiling further could be a waste of money.
I will say it, it is NOT 100% neccessary. It is nice to have new parts, but in my experience we have always used scrapped parts. This year is the first year that my team will get an all new electrical board. And I am very excited. However, of your team doesnt need to spend the money on electrical board because yall have a limited budget then I would say focus on the more important bits, such as drivetrain, KoP, and mechanisms. The electrical board will typically cost less minus the RoboRio which comes in KoP. And I am sure teams would love to help out with giving electrical supplies. Whereas, if you ask a team for a brand spanking nee drive train then you might be out of luck.
Only for rookies. For veterans (or rookies that need a second one) it’s $435 from AndyMark. Might be another supplier around but that’s the FRC price.
RoboRio’s are expensive, I know it. Either way focus on the more expensive and necessary things ya know.
Edit: not saying motor controllers and PCM’s arnt necessary just cheaper and teams tend to have a nice stash of those
national instruments sells one but for about $1000.
our team has one replacement of a roborio, pdp, vrm, pcm, and and infinate number of RSLs. You know when you disassemble an old robot that work on a c rio and you put the c-rio in the closet with the rest of the old stuff but you put the rsls with your other rsls. I think that it really depends on your team. either way you should still have spares. we bring about 4 spare tallons to each competition. But we have more of all of the components that we can take off of programming practice bots at our build site
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