Defcon 14 DefconBots Rules

[sciguy]

size and angles

I stumbled across this contest and thought it would be a good fit for another project I am considering, building a remote camera that can follow (GPS or burn signature) a 9 foot ‘model’ rocket lifting off and gaining Mach 1.2 at T+1.4s.

This event takes place in September 2006 and since Defcon takes place before this I might be able to combine both projects and test-drive the servo setup and steering.

Of course the servo assembly would be quite bulky and heavy, as it would have to handle a 6 pound receiver assembly for the (2nd) on-board camera, at excessive speed, so I might find that weight handling capabilities, speed requirements and precision might not be achieved at a reasonable cost. Although I still would have to design the optical target recognition and tracking software I am willing to try..

Although the rules list that there are no price and weight restrictions, I would like to confirm that if I do show up with a, say, 18 pound design (excluding marker) that is as bulky as a cubic foot (and a half?) I will not be frowned upon

Also, will there be provisions for setups that have to be lifted off the ground, as tripods will not cut it in many cases, and tables might not bring the units far enough off the ground?

Now I come to think of it, it would be great to know the max angles required.

Thx.

sounds like you are headed to Black Rock in September... (I fly too). I had thought about a 23000 ton Bolo design with inifinite repeaters, but I decided that the floor wouldn't take the weight and the doors were not big enough to get it in the room. The only consideration for size and weight will be shipping whatever is created to defcon (okay, making sure the floor can stand the weight). 18 pounds is light weight especially for the tracking you are trying to accomplish following a bird going 1000fps at t+1.4 seconds. You should be able to wipe all all targets in less than 10 seconds if you can follow a rocket going 1.2 mach. Personally, I would suggest bringing whatever stand you need unless sitting it on a table will be okay. Also, angles are already defined basically given the the targets will be ten feet away and contained within a five by five foot area.

[FlyingDutchman]

Good call about Balls! I was just there - awesome..

The problem is that I am just getting into the servo control mechanism, so yes – floor integrity might be a problem after all is said and done. Of course I would want to be somewhat removed from the actual launch tower due to smoke (solids) and the occasional CATO, so speeds might be achievable.

Speed and size of targets will have impact as well of course..

As a side note: I am assuming there will be ample protection against rogue guns and minor software glitches. Mandatory master power switch, etc. ?

[sciguy]

Balls and more...

Good call about Balls! I was just there - awesome..

The problem is that I am just getting into the servo control mechanism, so yes – floor integrity might be a problem after all is said and done. Of course I would want to be somewhat removed from the actual launch tower due to smoke (solids) and the occasional CATO, so speeds might be achievable.

Speed and size of targets will have impact as well of course..

As a side note: I am assuming there will be ample protection against rogue guns and minor software glitches. Mandatory master power switch, etc. ?

been a member of Tripoli for years... I fly regular composites instead of EX though.

for movement, I would have limit switches that could be changed from your rocket usage to tighter spans for defcon. Holding on to the extension cord might be a fair idea if you think your machine would go rogue...

[FlyingDutchman]

Yeah,

I fly mostly certified, but have attended Balls several times.

I'll install a self destrcut switch

[sciguy]

Yeah,

I fly mostly certified, but have attended Balls several times.

I'll install a self destrcut switch

a dead man's switch might be appropriate - one where the device will frag airsoft pellets...

[wwweb]

speed question

Here are my questions relating to the speed of the projectile
1. Is there a limit on the speed of the projectile? A .68" rubber ball can be propelled to 300fps with ease(covering the distance to the target in 1/30s). Is this too high of a speed for the contest as it might cause damage to the targets?
2. Is there a shots per second rule? Would for example a robot firing 3 shots(one at the target,one to left and one to the right) in 3/20 of a second be allowed under contest rules.

Thank you,
wwweb

[kallahar]

Speed Issues:

1) FPS: Pretty much open, most official guns fire at < 200fps so please target something in that range. You don't need something really strong, you need something really accurate. To protect the audience there will be a backstop to contain the shots, and a lexan shield in case the gun rotates too far toward the crowd.

2) Shots/Sec: Unlimited, the reference design I have can fire about 5 per second at full speed.

3) Weight: Just remember that UPS charges a ton to ship large heavy packages. People within driving distance of Vegas are lucky :) You'll also have to be able to lug it to the hotel and set it up on a standard hotel room floor.

4) Stand: You provide your own stand, tables/chairs/home depot will be available.

On the rocket tracking idea - very cool :) The only problem I see is that the rocket cam tracks over about a 90+ degree range, whereas for defcon you just need high accuracy over a 28 degree range (5' wide/tall at 10' distance).

[?sleepy_tiger]

This is an interesting site detailing the creation of a sentry gun that fires BB's:

http://cs-people.bu.edu/aaron/turret/turret.htm

Even though the gun uses machine vision to track moving targets, its general design could easily be modified to the specifications of the contest.

[sciguy]

This is an interesting site detailing the creation of a sentry gun that fires BB's:

http://cs-people.bu.edu/aaron/turret/turret.htm

Even though the gun uses machine vision to track moving targets, its general design could easily be modified to the specifications of the contest.

interesting machine. The transport would need to be a whole lot more accurate and stable given the targets that will be on the shelves though. The basic idea is right though... we have 1" diameter targets that we need to shoot at ten feet. I am still looking at repeatability with the typical airsoft gun to see what variation there is in order to make sure the entire system can maintain the accuracy necessary.

[kallahar]

Here's a few tips I've learned so far:

1) The gun vibrates a *lot*, so any electronics on the gun need to be shock mounted (just stick a rubber washer somewhere).
2) That vibration will unscrew anything. So use locking washers or some means to lock screws down.
3) You want a heavy base to mount it on, otherwise the vibrations will cause the platform to "walk".

[sciguy]

Here's a few tips I've learned so far:

1) The gun vibrates a *lot*, so any electronics on the gun need to be shock mounted (just stick a rubber washer somewhere).
2) That vibration will unscrew anything. So use locking washers or some means to lock screws down.
3) You want a heavy base to mount it on, otherwise the vibrations will cause the platform to "walk".

actually, I would ditch the outside of the gun and use the mechanism inside (some of the guns use a self-contained mechanism - motor, piston, spring, etc all wrapped up in a plastic housing inside the gun). The whole gun is bascially a lot of unnecessary plastic to swing around and the moment of inertia will kill your stability unless you always give the gun time to "settle" into position.

You are right about vibration - use lock washers, lock nuts, and/or medium Loctite on the screws.

[sciguy]

Progress...

Got my first printed circuit board back and the second one (turret/gun control) should be coming in a few weeks. Designing the controls systems from scratch rather than using a laptop (I really wanted to challenge myself). Managed to find all the optics I need for the targetting system. Still have the Main control and the Targetting Computer to go. Anyone else getting things together?

Still have to build a target range, but that won't be until spring time. Lots of machining to do to for the turret, housing, and gun. Followed by a whole lot of custom software... Looking forward to next summer as long as nothing major gets thrown in the gears.

[sciguy]

more progress...

really quiet in here... (I can't be the only one)

got the machining done for the horizontal drive and a conceptual design finished for the vertical drive mechanism. Boards come back this week to control the gun and the turret. Still need to send the video analyzer board out, but I won't do that until I prove the first design for the turret control board. Going to be home for a few weeks to celebrate Thanksgiving, so I will be turning my attention to the software during that time. Hope all the lurkers have a great Thanksgiving!

[kallahar]

Wow, very cool progress :) Want to post photos of it?

I'll be moving to a new house soon, but right after that I'll try to finish the targets and the scoring system, then write some simple targeting software to help those who need a boost.

Kallahar

[wsbpress]

Each round will be 5 minutes long. You get two rounds; only your best score will be counted. Best score wins, in the event of a tie the fastest time wins.

So just to make sure I understand this correctly, time is only a factor in the event of a tie?

Also what happens if a target is hit and spun sideways? Will all the targets be round? Including the moving/spinning ones?