Pimping the Pit Cart

Technical Technical Discussion
1

Hey Everyone, my team is planning on redesigning our pit cart this fall, cus our old cart … well, it served it’s purpose, but it needs to go.

So, does anyone have any ideas for what we could do to the cart?? All ideas accepted ;D (aka, minifridge/microwave for the in-between match munchies lol.)

Also, we’re thinking about putting under carriage lights on the bottom of the cart, does anyone know of any good websites that you can buy undercarriage lights/ leds off of?

And this is the robot pulling cart, not just a random tool box hauling cart.

2

I am confused by what you mean by pit cart, is that the one you use to drag around the robot or is it just to bring in totes and other pit materials? Either way it should be smaller than 36 inches on one side to fit through doors. Xoxide is a good site for lights. How do you plan on powering it?

3

Lighting at http://superbrightleds.com/ is pretty good. Their RGB bars can produce some astounding color effects.

OK, when you’re done pimping it up, how about a nod to practicality? Our cart is made from 1.5" 80/20, with a Craftsman 3-drawer tool chest* on each end. This leaves about a 16" space between for batteries, gloves and such. Advantage is you always have all your tools with you (big advantage in semifinals and beyond), disadvantage is you have to keep it neat and orderly. Doubles as a crate carrier on load-in and load-out. We use short (8") pieces of 80/20 installed vertically to support the robot so it cannot fall off.

*The kind that usually goes in the middle, no top hinged lid, with “griplatch” drawers so they don’t slide open by accident.

EDIT: Our also fits inside a standard bus luggage compartment when we move the handle (2 screws)

4

My team is (was?) making a new cart this summer and fall. Some things we considered include width (no more than 32 inches for us, as the MN regional venue required really narrow carts), ease of mobility (would it steer better with 4 casters / omnis or 2 caster 2 traction? fixed or rope handle?), center of gravity, robot security, wheel size (for rolling over bumps) and storage space. Ultimately my team decided to build a 2 / 2 cart with a fixed handlebar for easy movement.

Good luck with your cart, and remember to think practically before you get to pimping. Some of the most useful carts I’ve seen have been relatively simple designs that can hold the robot and a battery or two.

5

Boy am I glad I subscribe to the CD RSS feed :slight_smile:

Perhaps I can elaborate. We are building a new cart to last us as long as FIRST lasts (forever). We’ve agreed on some sort of lifting mechanism (suggestions here are appreciated), and that it has to be narrow enough to go through a door, as well on the coach bus we plan on taking to nationals. As far as wheel base goes, I think working on a robot on a 4 caster setup will be bothersome. Unless they lock somehow. We were considering mounting a tool chest on it, but I don’t have the most recent plans (I attended to beta test meeting rather than the cart meeting).

EDIT: And we want would prolly power it off a robot battery.

Personally, I think the biggest problem will be with the lift, and keeping the cart steady while it lifts. Our current cart does this, and it has almost tipped at least once (good thing our pit crew caught it)

6

Unfortunately Xoxide is just going out of business :frowning: they had nice prices and a pretty good selection.

Frozen CPU seems to be pretty closely priced on Cold Cathodes and LEDs and Such (unfortunately Yate Loons (cheap and good fans)) are more expensive there :confused:

Dimensions are a must.

I was looking at doing a 3x3 ft crate for my team, but when in use it would be opened up so 1.5 feet by 6 feet.

7

Thanks Mentor Dan, for filling in the technical info that my post was lacking in. =P

8

I had some ideas for a cart based on the Home Depot green “gardening cart” which we used one season but never really had liked. We still use a grey two level plastic cart which held the robot on the top (with some metal bar supports) and batteries, tools, etc on the bottom. No one really followed thru with my ideas, but each year we get closer to someone building THE cart.

Most of my ideas are based on watching the cart in action in the pit, and may not be practical in reality. As always, design on paper and do plenty of “what ifs” before building!

The platform, as I said, is based on the HD gardening cart without the four removable sides. It has big 10" wheels for stability over uneven surfaces and a steer-bar. The steer-bar has to be removable – in the pit it’s a hazzard when down and in the way when up. Between the wheels down the middle is a slideout tray for batteries and chargers – I figure about 7 or 8 slots maximum, and slide out the back. Between the left and right set of wheels is enough room for two toolboxes.

A lift mechanism is vital. The cart itself is about 14" high; with a robot sitting on it, it’ll have about 6" to spare under a 6’-8" door, which is about the lowest standard door. Yeah, I know: you know a door that’s even lower, but we’re not talking about your grandmother’s house! :p! Most “modern” doors are 7 foot.

But most years it’s not the top of the robot that needs worked on! Bending over or squatting isn’t the best way to work. Here’s where my design needs more field work – use a x-cross scissor-lift inside the robot wheels. Use student power to do the lifting and lowering – there should be plenty of them in the pit anyway. I’d tell you more but the patent papers and the design aren’t complete. :wink:

Why inside the wheels? More for simplicity and out-of-the-way-ness. All you need is a frame that supports the robot on the robot frame, not the wheels. And if you have to change a wheel, the cart isn’t in the way. As I drew it out it lifts the robot to about 38" up, not exactly eye level to the wheels, but good enough. I also figure that while the lift part can be standardized, the actual under-robot supports will change from year to year, depending how the robot undercarriage is arranged.

Still when carrying the robot the cart is still mostly hidden, as it should be, and it’s minimal size should allow it to fit in the crate.

9

Okay, I can probably think up a reason why the carts have to be 32" wide, but with the robot at 34-1/2" wide with bumpers (2008 rules, when I did the cart drawing), how does that work?

PS-- I think the HD cart is 26" wide; I missed showing a dimension. :o

10

Bumpers “squish” sliding through the door, if I remember correctly. It was more like 35 inches, but fabric still slid along it. Not too fun.