View Full Version : FRC/VEX Challenge
Rick TYler
17-03-2006, 01:02
With so many FRC people buying VEX kits now that they are on sale, I got to thinking about what to do with a VEX robot.
So, I went out and bought five 4-inch mini Poof balls. John, David and I are going to build a couple of quarter-scale Aim High robots shooting mini-Poofs. Just for fun. We'll post pictures and video links when we get it working. Is anyone else interested in trying this?
LightWaves1636
17-03-2006, 02:11
our teacher bought a kit too and we were thinking of a similar idea
Ben Piecuch
17-03-2006, 08:30
If you're building a 1/4 scale, I don't think a 4" poof ball is going to be the right size. 7"/4" >> 1/4... The raquet balls used in this years' VEX game are pretty good for a 1/3 scale game, as the balls are 2 1/4" in diameter.
Team 40 did just exactly this, and demo'd some of their robots at the BAE and UTC regionals. They had probably 6 or 7 different designs, including omni-drives, tread drives, swerve, etc... For balls, they found some of those "stress relief" balls that you squeeze to relieve, well, stress. They're about the same size as the raquet ball, but have the same "squishiness" factor as the poof balls. It was a VERY nice setup, and I'm hoping that we can build a copy of our '06 robot with VEX, just like we did with our '05 robot.
I'm a huge fan of VEX, and I think that it's participation can rival FRC in just a couple of years. The matches are as exciting, the quality of the robots are on par with FRC, and the kids can truly build 100% of it. If the low cost doesn't grab your attention, they could you please pass some of that extra cash our way? :)
BTW, there's a whitepaper somewhere here, showing the advantages of using VEX for prototyping and demonstrations. I think it fits very nicely with where I hope this thread will go.
VEX Whitepaper (http://www.chiefdelphi.com/media/papers/1716)
BEN
I have that idea as well, my Dad and I came up with it when my brother asked me if we could have some robot he could bring in for school in 2 weeks. I'll put some pictures up as well when I have them.
BTW, there's a whitepaper somewhere here, showing the advantages of using VEX for prototyping and demonstrations. I think it fits very nicely with where I hope this thread will go. (I'll try to find it and post the link)
BENAlso note that there will be presentations at the 2006 FIRST Robotics Conference (http://www.usfirst.org/robotics/2006/2006_cmp_conference_agenda.pdf) in April in Atlanta:
Using Vex to Supercharge Your FRC Team - Dan Larochelle & Donn Griffith and
Simplified Programming using easyC and WPILib for FRC and FVC - Dan Larochelle & Brad Miller
More information on Team 40's Mini FRC can be found in this thread:
http://www.chiefdelphi.com/forums/showthread.php?p=472222#post472222
irishninja
17-03-2006, 12:12
I'm going to try after I play more with the VEX. They should definatley have VEX competitions of the FRC game. I noticed thaat FIRST used the 2004 game as the VEX competition last year. It was cool to see similar designs. First I want to experiment with the rest of the kit though before trying.
Rick TYler
17-03-2006, 12:33
If you're building a 1/4 scale, I don't think a 4" poof ball is going to be the right size. 7"/4" >> 1/4... The raquet balls used in this years' VEX game are pretty good for a 1/3 scale game, as the balls are 2 1/4" in diameter.
Racquet balls -- check. Thanks for the idea.
Using 4" mini-Poofs in place of 7" balls isn't as silly as it sounds on the surface. The diameter is, as you say, not 4:1, but it's not just a matter of diameter. The volume of a sphere is 4/3piR^3. To find the ratio of volume, X: X(4/3pi2^3)=(4/3pi3.5^3), or 8X=42.875, or a ratio of roughly 5:1. So, the size is too big, but the weight is not. The balls are a little unwieldy for the average VEX-size robot, but the weight isn't bad. There won't be any 25-ball hoppers in this virtual challenge... I don't think.
We used these https://www.centurynovelty.com/detail_309_163-018.html
in our Mini FRC competition. They are exactly 1/3 the size of poof balls, but much lighter. However their density and "squishiness" factor was very close to the poof balls.
skimoose
25-03-2006, 10:25
Team 40's mini Aim High Vex game actually used 2.5" foam "stress" balls. Similar to these balls. (http://www.toys2wish4.com/smfasqba.html) There mass is much closer to the mass of a poof ball.
Racquetballs are rather heavy, we couldn't make a decent shooter with the vex motors, but add an old Victor 883 and an old 6V. FP motor and you've got a nice racquetball shooter. :cool:
Does anyone know what kind of stores would carry the 2.5" size stress balls? We've looked a few places and the closest thing we've been able to find is squishy tennis balls, which are still about twice as heavy as the one stress ball we currently have.
Our mini-robot for this year's game is very near completion; we need to drill and attach 2 more plates, then program it and do a final test, but it is otherwise finished right now.
skimoose
26-03-2006, 21:30
These stress balls are used as promotional give-aways by companies. You can find them online or at a business that specializes in promotional products for business. Online just google "stress ball".
look 3 posts up, i gave the link of the ones we used, they ship very quickly too!
i wasn't really able to find any in stores cuz it's kind of a weird hit or miss type thing.
Jay Trzaskos
26-03-2006, 21:44
I actually designed a game using the 4 inch poof balls that was similar to Zone Zeal for our Junior High kids to play. That reminds me, I have yet to build my bot for it...
irishninja
26-03-2006, 22:07
My friend and I attempted to build a flywheel out of VEX parts to shoot ping pong balls but it didn't work too well. We had the gear kit, we went from the biggest possible gear to the smallest possible gear and that was connected to a medium gear connected to a small gear. Basically we were trying to attain as much speed as possible but it only was able to shoot a pingpong ball like a foot. Anyone have any ideas?
I was looking more for balls I could find in actual stores without having to order online. We will order online if necessary but we kind of need them right now, so I was more interested in somewhere we could just drive down to and get a few. I've been told Walgreens or a similar place might be good for stress balls, any other ideas?
Making a flywheel out of Vex parts is very possible, we've done it using two of the 2-1/4" wheels (with the tread on). The previous gearing ended up being a 1:24 ratio with a single motor, and we got the ball to shoot 3-4 feet in front of the robot (that is the distance until it hit the ground, from a shooter about 18" tall mounted about 12" behind the front facing forward). The current gearing is a 1:40 with two motors, but we need to reprogram before we can test it, so I will have the results of that tommorow.
Our's is finished!
http://www.chiefdelphi.com/forums/showthread.php?p=482566#post482566
How is everyone else's robots going?
Our's is finished!
http://www.chiefdelphi.com/forums/showthread.php?p=482566#post482566
How is everyone else's robots going?
Something for your programmer:
This might sound a little crazy, but hey, it might work.
Ok, the VEX controller uses the same processor as the '05 Robot Controller for FRC. And, the CMUcam and CMUcam2 are inherently the same, except for this year's being DSP based.
The VEX controller's PWM Periods and Pulse-Widths are exactly the same as those from the FRC controller. Therefore, with very minimal alteration, Kevin Watson's camera code should run on a VEX controller. The only thing you'll have to watch is the amount of flash memory remaining in the processor, as it is about 1/4 the amount available in this year's controller :ahh:
Anyhow, just something I thought about while working on my Radio Control / Semi Autonomous Goose Chaser. (Its an old power wheels car of mine which I am upgrading with a new electrical system and making it Microprocessor controlled)
Good Luck Guys! I really like the 1/4 scale Aim High idea keep running with it. :D
Kevin Kolodziej
03-04-2006, 23:18
I too had this idea with all my new VEX pieces. I'm not making an exact copy of the 1675 robot though, but something close enough (where are those VEX worm gears when you need them????). I'm having issues with my conveyor (both hardware and time...darn you college!), but the shooter works great. I'm using ping pong balls instead of the stress balls, though, so its a little differet. Check it out: VEX Shooter (http://people.msoe.edu/~kolodzik/VEX/vex%20shoot/)
Good luck!
Kev
I too had this idea with all my new VEX pieces. I'm not making an exact copy of the 1675 robot though, but something close enough (where are those VEX worm gears when you need them????). I'm having issues with my conveyor (both hardware and time...darn you college!), but the shooter works great. I'm using ping pong balls instead of the stress balls, though, so its a little differet. Check it out: VEX Shooter (http://people.msoe.edu/~kolodzik/VEX/vex%20shoot/)
Good luck!
Kev
One heck of a speed increase off the shaft of a VEX motor. Nice 1/4 scale shooter, fast too.
This robot wasn't a copy of our robot from this year, just one meant to play a smaller version of this year's game.
I'm currently planning on testing various sensors on this in the off season (I plan to make a base equipped with encoders, sonar, an accelerometer, a gyro, and maybe something else too), but not on this robot as we wanted to finish quickly and didn't design this robot with a very easily accessible controller (I doubt any sensor wires would fit right now). That and the turning is not very good even after removing the tread from the 5" wheels.
That's a good shooter there. What kind of gearing are you currently using for it?
Let's keep seeing these fun VEX bots!
Kevin Kolodziej
04-04-2006, 09:42
That's a good shooter there. What kind of gearing are you currently using for it?
I have the motor shaft driving a 60 tooth gear, which drives a 12 tooth gear on the same shaft as the 48 tooth chain sprocket, which drives the 10 tooth sprocket on each wheel. So that would be 5/1 * 4.8/1 = 24/1. Sad thing is I just put stuff together and hoped it worked. As you can see in the first picture, I shredded one of the servo gears on the first attempt...
Kev
I have the motor shaft driving a 60 tooth gear, which drives a 12 tooth gear on the same shaft as the 48 tooth chain sprocket, which drives the 10 tooth sprocket on each wheel. So that would be 5/1 * 4.8/1 = 24/1. Sad thing is I just put stuff together and hoped it worked. As you can see in the first picture, I shredded one of the servo gears on the first attempt...
Kev
Are you planning on using just a single motor for the shooter or are you going to add more motors to it? I would say gear it up more but that wouldn't be a very good idea without additional motors.
Kevin Kolodziej
04-04-2006, 11:37
Are you planning on using just a single motor for the shooter or are you going to add more motors to it? I would say gear it up more but that wouldn't be a very good idea without additional motors.
I am only using one motor and it is working beautifully. I should actually reduce it just a bit if I'm going for a true scale representation. I'm probably asking for trouble with this setup, but hey...thats what happens when an architect builds such devices.
Kev
Lil' Lavery
04-04-2006, 15:18
If I ever get some spare time/parts to good around with I'm considering making a Vex Aim High bot. Probably going to use ping pong balls from another Vex game 116 runs. Wouldn't be a copy of 116's bot, probably closer to 254 or 1731.
Once spring is out and we are back at school, I am going to attempt to make a copy of our robot turrett and all. This ought to be fun. These robots could be great for outreach opportunities and displaying the capabilities of VEX.
Greg Needel
04-04-2006, 15:55
if you are looking to play a game with your vex kits....we are going to be having a vex competition at the Ra Cha Cha Off season. A custom game that is playable by both "sqarebots" and unlimited robots. We are hoping to have the rules released before the end of the school year so teams have plenty of time to build robots to compete. The Ra Cha Cha is in Rochester NY the weekend of October 28th and 29th 2006. More information on the offseason and the vex competition will be posted after the championship.
Francis-134
04-04-2006, 15:59
Hey, if anyone was curious, a video of Team 40's robots can be found here:
http://video.google.com/videoplay?docid=8078364906389058129
This video shows off the design process as we went from basic drawings, to our first revisions to the final product. We have actually run a number of "matches" using these robots and it has turned out quite a bit like the current game; shooters get pushed around, dumpers can sneak through, and anyone left alone in the "key" will score lots of points. We were thinking of finding a way to mount a camera onto our field and find some way to make it work with the Vex controller as well, but we've been kinda busy with this big robot thing (who needs em anyways :rolleyes: ).
I am only using one motor and it is working beautifully. I should actually reduce it just a bit if I'm going for a true scale representation. I'm probably asking for trouble with this setup, but hey...thats what happens when an architect builds such devices.
Kev
That's true, if we're going for scale I'm willing to bet ours is probably illegal (or close to it).
I don't really see a problem with the setup right now.
I would be interested in Ra Cha Cha, but probably more as a "what happened there" thing. I don't think our team would be flying out there, I know that.
Were those VEX kits for 40 all from the club, or did people buy their own kits and parts and use them for the prototyping?
Dan Zollman
05-04-2006, 20:01
We had a Vex bot called Runt at the Philadelphia Regional, which is a small version of our FRC robot Dawgma I. It's not an actual copy or scale model, but it picks up tennis balls with one roller and dumps them into a small wooden corner goal. I don't have any pictures at the moment.
Francis-134
05-04-2006, 20:27
Were those VEX kits for 40 all from the club, or did people buy their own kits and parts and use them for the prototyping?
All of the parts belong to our team, to an extent. Intelitek (the makers of easyC for Vex and FRC) is our sponsor, and because of the work they are doing with Vex, there is a cabinet full of Vex parts available to us. Also, most of the robots were constructed with (a lot) more than one kit, and all of them used non-standard Vex parts (lexan, perf, Fischer Price motors :) ).
I was wondering simply because looking at what those robots had it would have required about 7 expansion kits for EACH robot in addition to the standard kit.
Francis-134
05-04-2006, 21:54
I was wondering simply because looking at what those robots had it would have required about 7 expansion kits for EACH robot in addition to the standard kit.
Although I would heistate to say 7 kits each, I would say that there were a lot of parts. I think we may have had about 5 metal kits, whatever was in the cabinet (remnants from 12+ kits) and some parts we bought directly from IFI, which is much cheaper if you only need one specific part. But yeah, we were pretty strapped for parts afterward (except for sevos, I think we have about 20 spares sitting around waiting to be used in our next creation).
vBulletin® v3.6.4, Copyright ©2000-2017, Jelsoft Enterprises Ltd.