Enough buying talk. Let's hear about ghettofab!

[Billfred]

Alright, so while the buying stuff debate rages on, I'm going to create a refuge.

Let's hear about your (either your or your team's) greatest moments at the art of ghettofab. Let's hear about your electrical tape team numbers and cobbled-together parts and transmissions that miraculously worked in competition!

It's time to celebrate the ugly, the how's-that-hold-together, the "I need a tetanus shot looking at it" creations!

[RogerR]

at the peachtree regional, we found that our robot was unable to climb the small steps. luckily a coach from 494 helped us build some 'sliders' out of some extra material the martians had (delrin, i believe), using a sawz-all and a hand drill. the sliders (along with a pneumatic cylinder) allowed us to get up onto the 6-inch platform in one bound.

the sliders are the white triangular pieces affixed to the front of the bot.

[ZACH P.]

Half the weight of our robot this last year was in zipties. Colorful zipties.

[Frank(Aflak)]

Originally Posted by RogerR

at the peachtree regional, we found that our robot was unable to climb the small steps. luckily a coach from 494 helped us build some 'sliders' out of some extra material the martians had (delrin, i believe), using a sawz-all and a hand drill. the sliders (along with a pneumatic cylinder) allowed us to get up onto the 6-inch platform in one bound.

the sliders are the white triangular pieces affixed to the front of the bot.

we used a 1/4" bolt as a cotter pin for our arms primary joint ("Its a quarter inch of hardened steel . . . it'll hold!").

We sheared that mug twice.

I think we broke every cotter pin in the arm at least once. It was nuts.

Haha, best ghettofab, though.

So we used 4 wheel tank drive, two drill motors, right? Not enough power to skid with 4x 12" pneumatic skyway wheels. So we used two pneumatic wheels in back, two hard rubber in front, but the hard rubber tires were a lesser diameter, and stilll too sticky anyway. So we went ghetto omniwheel: we drilled .9" holes around the outside of the hard rubber tires and super-glued 1" marbles into them. It worked great. And it set us apart. Good stuff.

[Matt]

You got to take a look at 1212. This year we won the Arizona regional. We had cardboard numbers, metal light shade, and a hose for the vacum. Just take a look at this.

[The Dude]

I have to agree with Matt we DEFINATELY have the ghettoist (is that a word?) robot around, just take a look at it, we have the ugliest robot in the world and yet we somehow won the arizona regional and got 22nd in Newton division at nats.

[Alaina]

I would say that 814's 2003 robot, Spicy Mustard, was 100% ghetto-fabulous.
Spicy was wooden. Very wooden. The chassis was made of 3/8" plywood, the arm pieces were made out of 1/8" plywood epoxies to high-density foam. The "lobster" claw was made the same. In order to make Spicy pretty, we used wood stain to give him some color, and covered the bumpers with this really UGLY upholstery.

We had a limit button that made the elbow motor stop once it was hit. But the top came off of the button and we didn't have time to replace it. So we bought one of those gardening knee pads, cut out a chunk of it and ziptied it to the section of the arm that hit the button.

Needless to say, Spicy is the most successful robot the team has ever made. We won Judge's Choice and Leadership in Controls, and were regional finalists.

[Conor Ryan]

i have to say First ghetto fab is definetly more creative then other ghetto fab just because of the fact that we can't use duct tape. But I have seen cars with engines held in there with just duct tape and zip ties.

[hacksaw692]

Oh dear... This thread has most definitly been hiding from me.

2002. My rookie year.
We attempted a 4 wheel chain driven trannie. What's interesting is that we didn't bother using any pillow blocks to hold down our shafts. Instead we hand fabricated (hacksaw and drill baby) little 1" x 4" strips of metal that were bent over the ends of the wheel shafts and bolted directly onto the chasis. This provided for slack in our chain and really bad alignment. To make up for the slack we placed a thick piece of rounded off, I think it was some kind of polycarbonate plastic, directly against the chain as a tensioner.

Something like this would be able to be driven around rather gently on tile or contrete. But of course this was a robotics competition. Instead of tile, there was carpet and instead of gentle driving... well yeah 2 minutes and what are you going to do with a robot? So the chain would just pop right off it's sprocket and we'd be sitting ducks.

I'm still wondering why we bothered to build it that way (hmm maybe it was a weight issue), but what did I know? I was a rookie at the time. Unfortunately, this is the sole reason why 692 likes to avoid chain drives.

Minor gehettofabulousness: 2003. Robot's team numbers were shaped out of electrical tape and attached on with (colored!) zip ties.

[JVN]

The Original 229 Ghetto-Fab Moment:
(Sponsored by Tom Schindler)

This all goes back to 2002.
In the 2002 game, in order to pick up the soccer balls, we had this giant roller on the front of our robot. This roller was basically a giant wooden cylinder coated in grippy-foam, with a steel shaft running through it.

We picked up the soccer balls through sheer energy transfer. We spun that baby up to high speed, and as soon as a soccer ball touched it, *bam* it got blasted up through this alum shoot into the goal. It wasn't the most elegant method of the season, but it probably was one of the simplest, and it worked pretty darn well. (Who was at Cleveland that year?)

Anyways... we drove this massive roller with a drill motor. Off the motor we had a 1:4 timing belt reduction (do the math, that's 5000 RPM kids). It wasn't the neatest setup either. First off, with that kind of reduction, it took a few seconds for the roller to get up to full speed, but from there on out, angular-momentum did the rest.

The drill motor was kinda just, crammed into a timing belt pulley, and setscrewed in place. The wooden roller wasn't completely on center on the shaft, and neither was the driving pulley. This meant, the entire assembly oscillated like crazy. Basically, the entire thing was held together with good feelings and luck.

Ghetto enough?
Not yet dear friends... it goes on.

Now, because of the way that drill was mounted, the shaft was basically cantilevered. Yes... crazy stress concentrations.

At Bash @ the beach that year, about midway through the competition, the drill motor shaft just sheared right off. This left the pinion inside the timing belt pulley. With no way to fix it, we were in a tough spot.

Enter Tom Schindler.
Tommy "the man" Schindler was kinda bumming around that day, and hopped onto our pit crew for a while. (This making him, the first ever, honorary 229er. Tommy was the original 229-lover, everyone else is just copying him.)

So Tom was around when this happened. As we were all scambling for a soluition... Tommy just said something like "Dude. Just epoxy it back together."

What? Are you crazy? Hmmm... it could actually work!

So... we crammed that drill back into the pulley, tried to get it as straight as we could, and just slathered on the epoxy. It actually held up for the rest of the competition.

The moral(s) of the story:
-Epoxy fixes everything
-Drill motor output torque isn't enough to shear epoxy
-Tom Schindler is the man.


That's all folks. Anyone else?

JV

[Pat Roche]

Originally Posted by JVN

The Original 229 Ghetto-Fab Moment:
(Sponsored by Tom Schindler)

The moral(s) of the story:
-Epoxy fixes everything
-Drill motor output torque isn't enough to shear epoxy
-Tom Schindler is the man.

JV

Back before my time on 134, the teams rookie season to be exact, 9 years ago, the robot was being built, and it was nearly complete, except for one small detail, there was no drive train. So as rookies, the team decided to go direct drive with wooden wheels. Well no one really knew how to attach the wheels. Well one student *coincidently a former Clarkson student* said to the advisor, 'hey why dont we just epoxy the wheels on the motors'. Well they did that, and somehow managed to place very high.

Gotta love the epoxy


-Pat

[phrontist]

Our whole robot was ghettofab, but here are some highlights:

1. Robot couldn't get up the second step, so we did the calculations and realized our arm wouldn't reach it. Everyone was thinking, "if only we could find a little hook-like object..." about a day before ship date we got an old theatre cane (the kind used to pull bad acts off stage) that we used on stagecrew. We drilled a hole in it and put the van door motor's shaft through it, and in turn bolted the van-door motor to the arm of our robot. The end result was a cane that could whip around and grab on to the bar (which it did!)
2. We didn't have front wheels, just some ghetto plexiglass "skids." In order to get up the steps we put a bunch of rollerblade wheels on the front of the bot. This worked suprisingly well.

Next year we have two new rules:

1. KISS sucks.
2. Zipties are evil.

[sanddrag]

At the 2004 Chatsworth Scrimmage our robot was very top-heavy and flipped over every match so we never got to use the hangar. We got to wondering what the robot would be like without the hanger, at least then we could climb the stair and shove other people off. So, we removed the 30-40 lb hangar and duct taped a Stack Attack bin lid to the robot to cover the drivetrain and other now exposed essentials and we played the next match. The robot did not flip at all but it bounced all over the place. So, to remedy that problem we went around asking every team for any spare metal they had and we duct taped it all together and then put it on our robot to bring it up to weight. I don't think we ever drove it that way though.

Towards the end of the LA regional we had a belt break on our hangar. Either we didn't have time to redo it or we couldn't find a turnbuckle so we used a zip tie to hold the ends of the belt together and tension it. Still works great to this day. On our 2003 robot Heather, we used a Zip tie to space a gear away from the chiaphua motor. That didn't last too long though.

On our 2004 robot, we had a lot of trouble turning so we sliced sump pump hose down the middle and zip tied it over two of the tires. It had ridges for forward traction but it would now slide sideways too. It turned like a dream. I think it was the cheapest fastest "omni wheel" ever made. We had a little trouble climbing the step so we switched over to pool hose which ripped and came off every match in the finals and it didn't turn nearly as well either. But at least we could climb the stairs.

[Ryan Foley]

So, heres 350's "ghettofab" entry.

That picture is of our 2004 ball collector (the drive train actually looks decent so it's not important) as it was at the BAE regional. Let me walk you through it part by part.

String- see all that neon yellow stuff? thats string and yess it is holding the frame together. Hey, tape cant be used to hold things together so string worked great. It gave the ball collector some flex too.

String 2- yes the white string going across the collectors sides is our "netting"

PVC Grippers- those white PVC things on top used to be the 2X ball grippers from the 2X arm we had until thursday of BAE. They are there so that they stop the ball collector from going inside the corral, they were added 3 matches in. Held on with bolts and string.

Wood- the frame pieces are wood, and the "L" brackets connecting them (where string isnt used) are metal. the metal and wood together looked terrible.

Wood 2: see those thin pieces of wood along the botton? Yep, scrap wood we picked up in the wood shop before heading to cometition friday. Added so that the balls roll better when we want to get them out.

Roller: the gray cylinder going across the front. A PVC pipe glued and bolted to the 2nd to last FP transmission gear (thanks to 121's great way to speed up the FP gearbox) with rubber stuff glued to the outside for grip. There is no axle, its held on to that little piece of scrap plywood (that is screwed onto the frame) using a 1/4 in bolt going through the end cap of the roller.

Winch: see that big hole on the plywood deck behind the ball collector? Well you can barely make it out but thats a seat motor we are using to raise and lower this thing. It's not speed controlled so the thing comes down as a controlled crash. The seat motor axle is spare key for the 5/8ths shaft. Oh yes, its 5 strands of string interlocked that we used as our winch cable. And no, the seat motor isnt strong enough to lift the ball collector back up all the way.

Pipe Insulation- spare stuff I have no idea where we got it but its used to cover the bolts holding the PVS grippers down and where the "winch cable" joins to the collector itself.

Oh yeah, you cant see it here, but our 350 signs were made friday morning out on the loading dock with spray paint.

No, the bot isnt painted at all. We dont have decorations except for all 20 or 30 of our license plate stickers.

Surprisingly the collector held up the whole competition. Although in our last match the front 2 vertical wood pieces snapped, so the entire top side was flapping around and flexible. Thanks to this, the ball collector could expand and actually hold more balls. So who else can say their bot works better broken?

<edit> sorry the picture is so small</edit>

[Ryan M.]

Our transmission kept stretching just enough to cause the gears to go past one another instead of engaging. No picture of it, unfortuantely, but we ended up just wrapping it in a gazillion rubberbands...