[DFTF] Budgeting for a Competitive Robot...
 

This is part of a series of posts called Drinking From The Firehose on getting Dr Joe back up to speed on All Things FIRST.

Today's topic:
Budgeting for a Competitive Robot...

Okay, we have finally come to the 500 lbs guerrilla in the room.

How much does a competitive FRC robot cost?

This is not an academic question. I have currently signed up for a 2nd Regional (thanks NASA!) but I only have $1,500 left in the account we've labeled “build a robot."

Can I build a competitive robot for $1,500 plus the KOPs?

Assets:

• I have some robot raw materials, probably not enough to build a robot but I guess ~80% of the way there (AL stock, some polycarb sheet, some wire, lots of zip ties, all the 10-24 screws & nuts you’d ever want, some #35 chain & master links, … ).
• I have a small shop (mini-mill, mini lathe, drill press, bandsaw, drop saw, belt/disk sander, marble block & height gauge, …).
• I have student labor (largely untrained at this point, but we will get there)

So… what I have to buy is

• sprockets
• bearings
• wheels
• motors
• gearboxes
• sensors/electronics
• pneumatic solenoid valves
• pneumatic cylinders
• Jaguars/Victors
• PWM Cables
• Bumpers
• 2CAN2?
• ??? 100's of other ticky tack things that add up

Here is what I would like folks to help me figure out:

Give me a base number:

• What does a competitive robot cost (all inclusive less KOP)?

Then break it down:

• Price for raw materials (AL, polycarb, screws, pop rivets, tie wraps, hold downs, pool noodles, nylon cloth, …)
• Price for the main drivetrain (assume use of 2 CIM + CIMpleBox + sensor from KOP to make a 6WD drop center chassis – add in special wheels, chain, sprockets, bearings, etc. that are not in the KOP)
• Price per Motor-driven Actuator (MA) include motor, gearbox, chain/sprockets, Jaguar/Victor, PWM/CAN cables, fuse, sensor? Also how many MAs should I plan on? WRT gearbox costs, assume that I am going to have to use stuff from Banebots and/or AndyMark because, while I design robot gearboxes for a living, I am pretty limited on the kind of stuff my kids can make with our shop.
• Price to “ante up” for pneumatics (assume KOP stuff pump, tanks, regs, switch,… include costs stuff needed to make the KOP stuff work).
• Price per Pnuematic-driver Actuator (PA) over and above ante price above include solenoid valve, cylinder, end fittings, plumbing, sensors …? Also how many PAs should I plan on? If there is a way to cheaply gain cost advantage by ganging valves (for example using a special N valve manifold that works well for FIRST and costs less per channel)
• Price for custom electronics (anything above and beyond the KOP stuff. I assume that the KOP angular rate sensor is acceptable, but what else do we need/want?)
• Other robot costs not included above (e.g. extra batteries)
• Finally, How many MAs and PAs total should I count on (assuming again 4 CIMs are used in the Chassis)?

So…

Don’t spare my feelings here. Tell it to me straight.



Do I need to cancel our plans to go to a second Regional? Maybe even THAT isn’t enough, if I need more, tell me now.



I’ll work to find the funds I need. But before I do that, I need to know what I need to raise...


Joe J.
Team Leader / Mentor
Team #3958
Schrodinger’s Cat
BC High, Boston MA

Re: [DFTF] Budgeting for a Competitive Robot...
 

If assuming this years kit stays roughly the same as last years kit when it comes to the kit bot. 1114 kitbot on steroids is a great starting point and can get you a competitive bot. The extra parts needed for the kitbot will cost you ~$400 including shipping from Andymark and then that would leave you with ~$1100 to build the rest of the robot and if done properly $1100 can get you a competitive robot. You just have to remember to keep it simple and to build within your means.

Re: [DFTF] Budgeting for a Competitive Robot...
 

With no old robots to rob for COTS I would say that you need $4000 dollars to build a single competitive robot.

$1500-2000
You need to buy transmissions and other power transmission hardware (gears, sprockets, chains) that can easily run this range with reasonable spares and failed concept fallout.

$200-300
Wire, nough said

$600-800
Motor controllers, you only get 4 in the kit of late and this is always the painful number to see.

$250
Fasteners: nuts, bolts, rivets, zipties, master links etc to stock up.

$200
Additional motors, you only get 2 of the CIMS in the kit and you need to buy more if we get to use 4-5 again this year. Banebots motors have had many issues and we never go into battle without spares anymore.

$200
Bearings: we use a lot of bearings and bushings. But we also build lots of spares and failed concepts.

$300
Bumper, fabric wood and pool noodles.

$1000
Shipping: to get the parts to you...

$500
Additional raw materials

$200
Solenoid valves and other pnuematic parts.

$200
Cutters for machine tools.

This is all best guess from memory. I know when you add all this up we easily spend $4000-5000 every year on the supplies to build a single robot. We also have a lot of spares, fallout from concepts that don't make the robot, and shipping costs to bring our robot in under the typical $3500 limit. I have to say with the cost of electronics consuming so much budget when we account our cost I would like to see it go to $4000. We are close every year to that limit, because we are honest to a fault with our accounting, and the electronics is a big factor.

Re: [DFTF] Budgeting for a Competitive Robot...
 

Unless I read the original post incorrectly, it appears he wants to run CIMple boxes, in which case he won't be spending this much money on the drive train, even if you buy spares for everything and buy an new set of wheels, say the 6" or 4" plaction.


As for battery costs, I'm going with a 6 battery total on my new team, so with 4 additional batteries it will costs $166 from AM, without shipping costs. However, you will also need additional battery chargers. I don't remember if the KOP includes chargers or not, so you may need to get 2 chargers in addition to the 4 you would get for your new batteries, and even if it came in previous kits, never count on something being in the kit.

Re: [DFTF] Budgeting for a Competitive Robot...
 

As Peter pointed out, shipping costs wind up being a huge part of a team's annual expenses. When you buy from AndyMark or McMaster-Carr, you often end up with capital that you can re-use from year to year (at least for training and prototyping). But when you spend $1000+ on shipping, that is money you will never see again.

There are a couple of things you can do to help mitigate this:

1. Find local suppliers! For bulky items like raw stock, nearby metal suppliers will save you a fortune on shipping in the long run (and if you sweet talk them, you can often work out deals to buy "at cost" or even have the materials donated to you). If you have a McMaster warehouse nearby, you are in luck!

2. Plan ahead. Ground shipping is much cheaper than next day air. The faster you go from "napkin sketch" to BOM, the more slack you will have in selecting less costly shipping methods.

3. Order in bulk. Many sellers (like OnlineMetals.com) offer free or discounted shipping for large orders.

Re: [DFTF] Budgeting for a Competitive Robot...
 

I don't intend this to be a call out, but there is a little danger in thinking this way. We designed a gearbox preseason last year on the assumption that the KoP gearbox was a Toughbox, and then they switched it out on us.

I would definitely not budget assuming a particular KoP gearbox.

Re: [DFTF] Budgeting for a Competitive Robot...
 

Dr. Joe, there is one thing that you will be very interested in. This started last year, and was pretty successful: the FIRST Choice program. Effectively, some items that maybe there aren't enough of for 2500 teams are put into a "store", first come first served, with all items in the "store" free. This can cut down costs on certain items, depending exactly what's in there. It's hosted at AndyMark's website, or was last year, which makes it fairly easy to place an AM order and have it arrive at about the same time.

IIRC, last year's included such items as some hand tools, an FTC starter kit, old but unused batteries, wire, and speed controllers.

Re: [DFTF] Budgeting for a Competitive Robot...
 

I checked my numbers I actually had a 2nd robot in there for drive base.
My assumption was based on 6wd with spares for wheel breakage and no ability to make custom gearboxes for mechanisms:
2 AM Planeteries ~$200
8x 6" performance wheels ~$300
8 drive sprockets ~$100
4 Mechanism sprockets ~$100
10 Hubs ~$150
4 P60 planeteries ~$260
Chain ~$50

For a Total of about $1150.

Re: [DFTF] Budgeting for a Competitive Robot...
 

Back in our early days, we used to spend $1,000+ per season on rush shipping for things we need. Now, we've become a little wiser and aren't paying for priority shipping ever. We just try and order in advance and wait the extra day or two. Actually, though, it's not that bad. IIRC, we can get orders from Andymark in 3-4 days in McMaster orders the next day, all without paying for express shipping. It's saved us a ton of money in the life of our team.

And, I think it's probably doable to get one good robot out of $1,500, if you spend your money wisely and think it through.

Re: [DFTF] Budgeting for a Competitive Robot...
 

True, I have been careful to not assume with my new team.

But the point I was trying to make (However badly I communicated it), he plans to use what's in the KOP for drive train, which I don't think would cost that much money to buy additional materials and spares for, even if it is a shifting gearbox (which I doubt will be the case).

Re: [DFTF] Budgeting for a Competitive Robot...
 

I believe our BOM came out to around $2500 last year, but I will have to check with last year's captain.

Off the top of my head I can think of a few major price sinks:
7 victors ~ $630
4 mecanum wheels ~ $400
4 Toughbox Nanos ~ $320 (plus we changed the gear ratio and output shaft, don't know the cost of that)
1 extra Digital Sidecar ~ $80
4 BaneBots planetary gearboxes ~ $260

That totals $1700 already, and we poured money into raw materials, spares and dozens of other parts. And a second bot.

Of course, if you manage to not waste an ounce of metal and never bust a part, you could definitely get away with $1500. However, you might want to build prototypes or field elements, too. It's hard to factor in the cost of everything that might come up in the build season, so if you can, try and get a bit more cushion for that budget.

Re: [DFTF] Budgeting for a Competitive Robot...
 

Our robots have cost between $1000 - $1500. so I would say your good. I don't have a breakdown list but, they were competitive robots.

Re: [DFTF] Budgeting for a Competitive Robot...
 

Unfortunately, I don't have a detailed break down of our costs available to me at the moment, but last season, we spent ~$7000 to build two "competitive" robots.

A lot of that is shipping; we don't meet often and decisions sometimes come late as a result. We're trying to be better about planning in advance.

I prioritize convenience over price, so we probably buy things that we could make and could save some money there, but I think spending a few hundred dollars more for a few days of extra practice is worth the expense.

We also burned A LOT of money on minibot development last season. Here's hoping that's an idea that never comes around again.

Re: [DFTF] Budgeting for a Competitive Robot...
 

I think this could be a bit easier if people just posted their BOM. We all had to make one.

Here is the BOM from the Discobots 2587 from last year. I think this version is from before our FIRST Regional so it changed a bit by the end of the season but for the most part everything is there.

Discobots BOM 2011

This only includes the parts that made it to the robot so you probably need to add as much as 50% to this for shipping and parts that weren't used, broken and backups.

Re: [DFTF] Budgeting for a Competitive Robot...
 

While true, we spent far more money that our BoM would indicate. The BoM shows that we met the rules, but it doesn't show the cost we incur in research, development and breaking stuff.