Enough buying talk. Let's hear about ghettofab!

[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...

[Joshua May]

OK, this is my team's specialty.

Flashback to 2003:
1) We were trying to figure out how to put the numbers on each side of the robot, so one of our software engineers actually took a popcorn tin, cut out a rectangle, and we put the numbers for mailboxes on it. Turns out, it worked quite well, even though it got torn to shreds. You can even see a snowman peeking through the numbers on the plate.
2) I counted, and at one point we had some 500 zip ties on our robot, holding everything together, including the gearbox and the motors.
3) For our stacking mechanism, which was built at the very last minute, we didn't have enough metal to finish the stacker. So we took some wood and cut it for the top of the stacking frame and the lifter. We then spray-painted the wood silver so that teams wouldn't notice that it was made of wood and thus vulnerable. We managed to fool everyone, even up close, into thinking that the wood was aluminum. That, my friends, is ghettofabulous.

[Billfred]

1293 was surprisingly low on ghettofab, due to the fact that we had no duct tape.

I think the biggest ghettofab moment we had was when we couldn't find Mrs. Sutton (our honcho of nearly all things non-robot), who had printed up our team numbers for the robot. We had to have team numbers, so we used the best thing we could think of...electrical tape.

And it was like that the entire Palmetto regional.

Off of the robot, however, we were kings. We needed a ball tee to practice our autonomous mode, but we didn't have any toilet flanges or anything. Our tee wound up being a lid off of a foam coffee cup (the kind with the indentation in the middle), a length of PVC pipe to fit, and the feeder tray off of a printer to work as a base. (I wound up using tin snips to cut out a perfect fit in the ridges.) It worked for a tee--whether it held up when our robot came stampeding through is another story.

[suneel112]

I have participated in at least two ghettofabs during my 3 years. The first one was 2002.

There was one advisor who insisted on having four, crab-movable and lifting up tank treads, which weighed in at 50 pounds. This only left room for one arm, and we could only haul one goal with all that power. We didn't do well at all that year, and instead of going to nationals (the last time they were held in Orlando ) , we went to the St. Louis Regional. There the other advisors and upperclassmen decided to remove two of the tank treads and replace them with the equivalent of aluminum casters. That gave us weight (about 20 pounds) to put the arm back on and we decided we would have to have a mechanism that goes back to the home zone (to score 10 points). We didn't know what to do until an advisor suggested measuring tape. So we put a roll of measuring tape on the top of the robot and had a FP motor shoot it backwards to the home zone. It worked quite well, and was made completely out of wood, completely on site without any machine shop.

This year (2004), our arm wasn't working with the high standards we hoped it would. Even when the pneumatic was pushed all the way in, the ball would still slip out. I suggested supergrip (which we used extensively last year) but it turned out we didn't have any. Then somebody suggested using a popped 2x ball to do the trick. We got a popped 2x ball (I don't remember whether it was form our kit or from our good friends on 447) , cut it into strips, and stretched it around the arms. We then used Zip Ties (Confucius' Law of FIRST: Know thy Ziptie ) to keep it on, and the only times a ball went out of the arm after that was when it was vigorously pushed out. Proof that Ghettofab works.

[spears312]

zip ties...

We originally had used this nice piece of getofab to hold our wench line up against the arm, and when it was time hang those things would go flying, but by the end of the build we had replace them with some medical tube and hooks which would actually stay intact and on the robot.

[Kyle Love]

This year 45 had a lot of "ghetto" stuff on it I think. Such as our pool floatie toy pads on the sides and rear. To our front gate we put on at nats that myself and Andy built in like 30 minutes. It was just lexan riveted on to a aluminum tube. It may have been ghetto by my terms but it was also P.I.M.P. HAHA!

-Kyle

[ngreen]

In the spirit of Dave's comments, I very much believe in the plastic trash can lid also. Our robot this year had an arm with suction. The suction cup: A wal-mart trash can lid with non-porrous foam contact glued to form a seal. To power it: A FP on a shop vac impeller. Other ghettofab parts. Thighmaster roller-pad to supposedly keep from running over the ball. Xerox machine parts used 4, coupler for different motors. To keep the winch from unraveling, a piece of plastic was put around the lead screw. Never came unraveled.

For last year: Edurobot wheels used to form grippers on arm. Held on with plastic automotive push-screws. Caster wheels for turning: We use go kart racing tires on both years robots and can make turning hard. When we had the two extra days we decide to put pneumatically actuated casters on the back to help turning. After plasma cutting a spot while everything is on the robot we fit the caster wheels that saved us from numerous tips into place.

Robovation ghettofab: I took the robovation bot to college with me for an open house booth. I realized the tiny tires weren't going to cut it so I saw that I had both foam board and electrical tape. Using the old hubs, foam board and electrical tape I made new wheels which worked great. More foamboard, duct tape, a three ring binder v piece: I build a protective shell with a scoop, side flaps, and a pusher on back with a duct tape hinge. Three ring binder and IFI parts, Gravis gamepad, velcro and 222 battery: Carryable Controls(all fit in the binder).

[Evan Austin]

Originally Posted by suneel112

Then somebody suggested using a popped 2x ball to do the trick. We got a popped 2x ball (I don't remember whether it was form our kit or from our good friends on 447) , cut it into strips, and stretched it around the arms.

If it was at Atlanta it could have been from us. I remember the ball, but I don't know what happened to the rest of it. We wrapped part of the ball around the grabbers on our robot to try and make them hold the ball better. It helped, but it didn't cure it completely.

We also had a problem with a shaft in our drivetrain gear reduction start binding on us in Atlanta. We had two gears on the shaft that were welded together with a spacer in between them, and we had them cotterpinned to the shaft so that the assembly would ride in bearings. After trying for a couple of hours to readjust the shaft to eliminate the bind, with no success, I had the idea to just remove the cotterpin and let the gears spin on the shaft. This worked very well, despite the fact that we now had steel spinning on steel, but it only had to last for 2 more days so why not go for it? We also got an added bonus by taking out the cotterpins in that our sprockets were now self aligning!

As for weight reduction, at Great Lakes last year our robot was about 3 pounds overweight. As a last chance attempt, myself and another team member got out our pocketknives and proceeded to trim the treads off the sides of our tires. It didn't get us 3 pounds, but when you have less than 1 hour left to be inspected for the regional, you'll do just about anything.

[M. Hicken]

well, our '02 and '03 bots were entirely ghetto. But last year we had about 3 days to ship, and we had no idea how to attach the flapper (think of a vaccume agitator)(SP and wrong term, but work with me). It was just some rubber strips screwed to a pvc tube. We were using the window motor to power it, we just got PC11, a high strength epoxy and glued to stupid thing on. It worked well for the 2 times we used it.

This year... ELECTRICAL TAPE!!!

[Sachiel7]

http://www.chiefdelphi.com/forums/pi...&quiet=Verbose

'nuf said.