1726 Beginning Week Three

We’re doing pretty well so far, we almost have the beta version of our robot built. All that needs to be made now to have a complete prototype bot is the part to move the balls from the floor to the top, which is mostly designed and should be done in the next few days, as well as some wire management and mounting of the electronics. Our robot as currently planned has a turreted shooter, which is loaded by a helix hopper and a roller on the floor. This all mounts on a wide format four wheel drive chassis.


Any comments or questions are greatly appreciated!

We’re having some trouble getting a good way to rotate. Can you explain how yours does?

We are posting photos of our build too.


(this might answer your question about how it rotates)

here is a up close image http://photos.project1726.org/displayimage.php?album=lastup&cat=0&pos=3
and here is the video of the pully system http://www.youtube.com/watch?v=50Q3ToSvbIg

What are you going to have feeding the balls into that shooter during competition? Are you using an auger? If so what is going keep the balls from shooting when you don’t want them to?

We are planning on using a helical path for the balls to follow upwards, with a center rotating part to drive them around and up the path. At the top will be another small roller that will pop them into the shooter. We need to get this all built and see how it works. We might need to make a gate to control the balls at the top.

this is how we are feeding thje balls to the turret http://www.youtube.com/watch?v=LlUgVpRckS8

Wow, quick good responses, thanks.

Awesome work guys. I have always admired your team.

Great work! It is awesome to see a proof of concept that a design like this can be done with simple components and fairly simple tools (from the looks of things).

We will be attempting a similar setup that we will begin working on shortly.

Judging from the pictures it looks like the was (or at least could be) done with basic wood working tools such as a jigsaw, table saw and a drill. Is that accurate?

Well…it maybe could…but we did use the lathe for some parts, like making the bearing holes in the roller end caps, and making shaft size adapters for the sprockets onto the transmission and motor shafts, and the output shaft for the Fisher Price little gearbox we made.

I think everything except that output shaft could be made without the lathe, if you were good at drilling holes into round things, and getting them properly centered.

I looked at the pictures which I greatly appreciate. And also thanks for the quick reply, but I’m still a little fuzzy. I can tell how it all goes together but what did you use to make it rotate. I mean what is that part exactly? Or is it custom? I really appreciate the video and pictures, our team is trying the same thing and I marvel at how quickly yours went together, we’re still stuck in auger land, but we’re quickly moving to the shooter. Just curious, why did you choose the one sided shooter like that? We had been looking at two smaller rollers on either the sides or the top and bottom but this looks simpler. What made you go with form of shooter?

Sorry, I should have specified what I was talking about. Of course it is much easier to use a lathe or mill for some of the shaft and bearing parts as close tolerances must be kept on those parts for the system to run well.

Provided we can CAD exactly what we need (and my CAD skills, while not great, should be sufficient) we do have access to a machinist that will assist us with small parts like the things you mentioned.

Once again, the pictures are awesome! It looks like you guys are making great progress. Now I just have to convince my team to be as transparent as you guys are (I guess we have to be taking pictures before we can be sharing them though…).

It’s a Southwest part…called a Swamp Cooler Blower Pulley. It’s a 12" diameter, 1/2" V belt pulley, which happens to have nice flat spokes that are perfect for cutting off and bolting to a piece of plywood. The magic trick is using 3/8" belt on it, so there’s an indent for the support bearings to ride in. (also we are going to put normal kit wheel bearings on it to replace the previous year KOP slide bearings)

Just curious, why did you choose the one sided shooter like that? We had been looking at two smaller rollers on either the sides or the top and bottom but this looks simpler. What made you go with form of shooter?

We tried it and it worked.

It’s interesting how this works out. It could be that some teams will copy some of our ideas, which I think is great. It could be that some of these teams will do a better job with their copy, than we did with the original! which is also great, although it takes some hard thinking to figure out how to explain this to all the team members…but eventually it seems that we realize that there’s an I in FIRST, and the I stands for Inspiration, not for “me”.

Besides, when we goof up, we get quick feedback! ask 842 about that :slight_smile:

We are doing a very similar design to yours except I think our shooter will be placed different from yours. I was just wondering if you were planning on controlling the speed of the shooter to adjust to various distances.

Looks GREAT!!


Kevin (programmer) says “yes! We’re planning on using the camera or an ultrasonic sensor to determine distance and adjust the shooter speed accordingly. Human control of the speed shows distance is controllable”

(he was in the kitchen eating cereal…so I asked him…)

This is the major thing we are worried about and unfortunately don’t have a great way to test before committing to a design.

Have you tested the effectiveness of altering the distance by changing wheel speed? If so, was spin up/spin down time a factor?

We didn’t have much time to mess with it tonight (got it firing just before it was time to close the shop :frowning: ) but we can test this tomorrow and see how effective motor speed is on distance. The roller is spinning at 3700 rpm from one CIM on a 5" roller and 1.5" compression, so spin up time might be a little higher than we expected, but once again, we’ll test that tomorrow :wink:

Oh okay that’s what we are looking forward to also we got the camera tracking the colors and following them but we have not had a chance to test the ability of judging distance. We are going to using 5" rollers as well but we are running a CIM at a 2:1 so we are more in the range of 2600 rpm. Hopefully we can get the shooter up the rest of the way tomorrow to be able to test distance by Wednesday…