agitator

@Clio Batali has joined the channel

@Clio Batali set the channel purpose: For those who hope to agitate, and discuss the means by which this would be best accomplished

@Jack Chapman has joined the channel

@Julian Bonifaci has joined the channel

@Cruz Strom has joined the channel

@Parker Hutchinson has joined the channel

@Lucas Rininger has joined the channel

@Finn Mander has joined the channel

@brian_bonifaci has joined the channel

@Jacob Barfield has joined the channel

@Adrianna Carter has joined the channel

@Jeremy Lipschutz has joined the channel

@Samantha Rosen has joined the channel

@Brian Hutchison has joined the channel

@Mike Rosen has joined the channel

@Ronan Bennett has joined the channel

@Dana Batali has joined the channel

@Alex Larson Freeman has joined the channel

@Enrique Chee has joined the channel

@Will Hobbs has joined the channel

@Jon Coonan has joined the channel

my primary concern with respect to the agitator is that we have not yet prototyped the mechanism by which the agitator feeds the shooter. Seems like this aspect has, so far, fallen between the cracks because we've divided these two subsystems into separate groups.

That's a really good point - it looks like this will be a weak point to watch out for. Are there any people (students and mentors) who would be interested in making sure this is addressed throughout design discussion and prototyping? This would require awareness and understanding of both the intake and launcher.

I will try, I do think that a major concern in this respect is making sure the launcher intake and our output are on the same level

@Chris Mentzer has joined the channel

more pix in the launcher thread

@Riyadth Al-Kazily has joined the channel

@Timo Lahtinen has joined the channel

@Kenneth Wiersema has joined the channel

@Lia Johansen has joined the channel

@Tom Wiggin has joined the channel

@Jack Stratton has joined the channel

@Tom Wiggin has left the channel

@Binnur Alkazily has joined the channel

@Cruz Strom, @brian_bonifaci, @Julian Bonifaci, just to make sure, we decided to go with a 4 bladed design without the cover plate, and have the top half of the carosel be made of polycarb with a very solid ejector rod, right?

I'll try to get my drawn design into the channel

Here is a link (hopefully) to my design

https://goo.gl/photos/fbvPEfSdLRKefZGb7

@Parker Hutchinson, do you want to make sure that this is what we have in cad?

also do you want to meet sometime so that I can fill you in on what we are doing?

@John Sachs has joined the channel

Yes, I think that's right.

OK, were going with this s

Part orders ? Materials ? otherwise nothing for Friday.

Jack, Can you send me ASAP, like in the next 10 min.

I want to be done with all orders tonight for Friday's session.

that was a cool video!!! Woot! :slightlysmilingface:

Jack, Did you look at all the polycarbs we have ? various thickness and perforated vs solid ?

no, i did not

Do you know what you thickness you need in terms of polycarb ?

1/4 in I believe is what they designed around

For the hooper ?

hopper

I think that .25" thick would probably work, I haven't really taken a good long look at the polycarb that we have so as of right now so I can't make a solid decision yet.

1/4in for blades

There are a few sheets of thin polycarbonate you could use for the hopper

ok, Thanks

this is waht was order last week: 0.118" Clear Polycarbonate Sheet - 24" x 24" $12.46 1 $12.46
0.06" Clear Polycarbonate Sheet - 24" x 24" $7.14 1 $7.14
0.03" Clear Polycarbonate Sheet - 24" x 48" $9.94 1 $9.94

no 1/4 inch

We have those yellow side panels from gaea that I believe are 1/4 in and I think there are also some other 1/4 in pieces

correct. So wait till Friday for polycarb and al order for agitator from online metal ? Will this agitate the subteam ?

I think that should be fine

I also think we may have some other pieces of aluminum that could work

ok, good night. Great job team on slack !!! Good luck with finals all.

What is the max height of the storage walls relative to the top of the frame?

I believe that we were going for having the walls be as tall as is legal, but a section would be lowered for the intake

So ~22 in from the ground?

yeah

Will the agitator/carousel have the ability to reliably push out a single ball into the shooter? That is, will we have a feedback sensor that the programmers can use to implement a "single shot" mode? It would probably be a very useful thing for aiming (under driver control), so that we can shoot out a single ball at a time while the robot is positioned, and then go full speed.

I'm thinking something like a limit switch pushed by a cam on the carousel each time a ball is released (so the motor can be stopped). Better yet, and optical sensor that is pointed at some reflective tape on the carousel.

If we don't do this, then we may lose a lot of balls during the aiming process.

We will have a encoder on our motor shaft, and a half rotation will release a ball, however if you want a limit switch to count the balls, I'm sure that it could be implemented.

The trouble with just an encoder is that we don't know where in the cycle of releasing a ball we are. Encoders are relative, and so we would need some other sensor to let us calibrate the "home" position. Once we know that, we can just use the encoder going forward, but each time the robot is powered on we would need to reset the carousel to the home position first.

And remember, it's not that I want a limit switch, but I'm suggesting that you (the team) probably want a limit switch (or something similar). Preferably not a limit switch that could break (which is why I suggested an optical sensor.

@Jim Carr has joined the channel

Current intake design. Does this work for you guys?

it should

What do you think about lowering the height of the "blender" portion of the design? I ask that because you basically lose all the storage space that is below the top of the cylinder, and I'm not sure there is a reason for needing it to be 7 inches tall.

If you mean the carousel, I have it in my notebook as 5 inches tall, which is the smallest we think it can be

Are we still going to have a cone of some sort on top of the central mounting point for the fins in the carousel to push the balls to the side?

No

i'm concerned that the exit point would cause us to lose important volume in the bin... The idea is that the ball can legally transit outside the robot envelope, so I'd guess that the height of the slot could be max-height - .5 * ball diameter... This might also suggest that the siide panels continue to the top of the mechanism.

Is this for the carousel/agitator or the intake?

When balls are store at the top of our hopper , are we going to exceed 24 inches in height ? What is the rule with game elements exceeding the required volume ?

@Jack Chapman : oops - as you say, I was referring to the intake, not the agitator, sorry.
@Enrique Chee : my reading is that the game elements aren't part of the robot-envelop rule. This, of course, should be double-checked by our rule masters.

That was my thought, but it was a question I was think about for the Q/A system

Encoder update: looks like we’ll be integrating the srx magnetic encoder instead of the AMT103 shaft encoder. Paul, Peter, and Samantha have been working on how this will work for the launcher, so you may want to talk to them about similar strategies for the agitator. The method you go with entirely depends on how/where you mount the motor, but it’s worth thinking about before our next meeting.

If you’re interested: http://www.ctr-electronics.com/downloads/pdf/Magnetic%20Encoder%20User's%20Guide.pdf (page 8 if you’re confused about mounting)

@Chris Rininger has joined the channel

I told someone I would ask my mom about stretchy fabric recommendations for ball storage, and she got back to me that something like this should work well: https://www.amazon.com/gp/aw/d/B0189YP7LU/ref=mpsa11?ie=UTF8&qid=1485796195&sr=8-1&pi=ACSX236SY340QL65&keywords=mesh+stretch+fabric&dpPl=1&dpID=619cstghoIL&ref=plSrch. I think it's like the fabric used on the office chairs with stretchy fabric backs

Thanks Chris, based on the reviews it looks stretchy enough. Does anyone else have thoughts?

you can also see through it a bit - a plus for the application

That should make it easier for the driving team

I know the idea of the stretchy fabric is to allow ball storage volume to expand outside the chassis volume into the bumper volume. Could you also have the floor be slack mesh and allow ball storage below the top of the agitator... and then once the volume is full somehow take up the slack so the balls raise up higher and pour into the top of the agitator? If workable could increase storage capacity.

What if the walls of the storage opened outward after the match started?

i believe the rule is: no part of the robot can extend beyond the established envelope. Even it's a flexible bag, i reckon that that would be against the rules... Still, I defer to the rulemasters.

@Paul Vibrans has joined the channel

If a referee sees the fabric extend beyond the bumpers and believes the bumpers are at the maximum for robot size, then a penalty will be called. We will have a

difficult time disputing this unless we can show our bumpers are substantially smaller than the maximum, which they are not. Arguing with judges is not considered gracious professionalism.

That is a good point Paul.

We should come up with ideas for tomorrow's meeting to prevent the fabric from going outside the bumper zone

Nothing can extend outside the frame perimeter ( Not bumper perimeter ).

true

Just to clarify, i believe it's only at the start of the match that everything has to be inside the frame perimeter. Once the match starts, you can extend outside the frame but you can't exceed the max volume, which in our case is pretty much defined by our bumper dimensions.

Correct . Thanks for clarifying.

A while back Riyadth shared a link to photos taken by FRC 2877 (Ligerbots) at the Steamworks announce, and one of them was of the turntable inside the boiler. It seems like they have a number of things they're doing to prevent jams - thought it might be useful to dig that up and share. Here's a link to the full set of pictures again in case anyone's interested: https://www.flickr.com/photos/ligerbots/sets/72157678872068725

@Kaedric Holt has joined the channel

Two quick questions, firstly, who is actually coming at 11 am tomorrow, and secondly, what do we think of making a second agitator instead of spare parts for the first?

I'll be there.

Saw this on CD this evening - similar design... https://www.chiefdelphi.com/media/photos/44246

I will be there

A second agitator is more important in my opinion than spare parts for the first. If needed, parts from the second agitator can be used as spares for the first.

When we say second agitator , do we mean a different design ? If not , let's focus on finishing the 1st one and mounting it on the robot . Once this is tested and works , then we make spare parts for the agitator which might be a complete identical 2nd one. Am I missing something?

I agree we need a combined agitator shooter asap to program... There's so many unknowns at the moment in terms of software control and tuning

With what we know now the second agitator should be the same as the first.

We found the shaft!

reposting: https://www.chiefdelphi.com/media/photos/44246

Whose researching ? Can't just rely on programming.

reposting : https://www.flickr.com/photos/ligerbots/sets/72157678872068725

The rope on he hopper fabric was beginning to come out at the end of the meeting tonight. Please fix this permanently tommorow

@John Sachs has left the channel

@Jon Coonan archived the channel