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Re: Robot Arm B/C [Trial]

Posted: July 19th, 2011, 2:31 pm
by harryk
I can't really say, but I've mostly been looking at the Parallax BASIC Stamp, its mostly a general controller and there are numerous online resources for code, so you may not have to do anything but plug it in

Re: Robot Arm B/C [Trial]

Posted: July 19th, 2011, 3:21 pm
by questionguy
harryk wrote:I can't really say, but I've mostly been looking at the Parallax BASIC Stamp, its mostly a general controller and there are numerous online resources for code, so you may not have to do anything but plug it in
Thanks, I'll check that out

Re: Robot Arm B/C [Trial]

Posted: July 19th, 2011, 3:22 pm
by ichaelm
I've used the BASIC stamp before. It is very simple to set up and program. You don't need to know anything about the memory organization or anything to use it. I used the BS1, which only had 14 bytes of user RAM, so for anything complex you'll need a BS2. The downside of using a BASIC stamp as opposed to other MCUs out there is that it has no ADC or DAC capabilities, and it has no way of timing internally other than a function that calls a delay loop, preventing you from doing anything while you wait for, say, your servo pulse. Actually, maybe they added stuff like that for some of the BS2s, I wouldn't know. Also, it has to be programmed in basic, which is a pretty crappy programming language unless you're just starting out. But nevertheless it's a pretty awesome piece of hardware. And way easier for beginners than the mainstream embedded MCUs
Ubermensch wrote:Are you allowed to use an adhesive to "grab" the objects, or must a physical grasping mechanism be used?
The trial rules don't specify, so either would be legal unless the rules changed (which they will, so don't get your hopes up).

By the way, in the trial rules if I remember correctly the arm needed to span a distance of about a meter. For those of you who have lego motors or vex motors or hobby servos at home, try testing a small piece of wood or metal a meter long (like a meterstick) attached to your motor and see if you can lift it? In my experience you need a pretty strong motor, which most servos aren't.

Re: Robot Arm B/C [Trial]

Posted: July 20th, 2011, 12:37 pm
by questionguy
For programming the bot, does that mean setting up the exact movements and putting those into the robot, similar to what NXT robots do? I looked more into some software but most of the ones I found cost money, so I'll have to keep searching. Between programming the robot arm and controlling it by radio frequency, such as using a vex kit, which would be most efficient? I'm leaning towards programming because it would provide more accurate results

Re: Robot Arm B/C [Trial]

Posted: July 20th, 2011, 5:07 pm
by blazer
When programming a custom robot such as a robot arm, you would have to program what inputs control what servos. The trial rules mandate that the robot must be controlled by some kind of remote, just as the sumo bot rules. Also, in the trial rules speed is not emphasized, which would be the main benefit of an autonomous arm. With such fine movements needed, programming an autonomous robot would be difficult; sensors could be used to achieve more precision, but they add to the complexity and price. Plus, the bonus jug's location can change so you would have to account for that. I am always an advocate for vex no matter how you want to build your robot because it is so user-friendly.

Re: Robot Arm B/C [Trial]

Posted: July 20th, 2011, 7:58 pm
by chalker
Ubermensch wrote:Are you allowed to use an adhesive to "grab" the objects, or must a physical grasping mechanism be used?
This is an interesting thought, however keep in mind that you need to also 'release' the objects. How would you go about doing that?

Re: Robot Arm B/C [Trial]

Posted: July 20th, 2011, 8:01 pm
by chalker
harryk wrote:I can't really say, but I've mostly been looking at the Parallax BASIC Stamp, its mostly a general controller and there are numerous online resources for code, so you may not have to do anything but plug it in

You might also want to look into the Arduino family of electronics: http://en.wikipedia.org/wiki/Arduino

Re: Robot Arm B/C [Trial]

Posted: July 20th, 2011, 8:54 pm
by ichaelm
I've never tried the arduino, but I hear they're pretty good. The reason why I used a basic stamp for JYC instead of an arduino is because the sales guy at parallax gave me a free sample (except for shipping) because I emailed them about my project. This was almost two years ago though, so don't count on that of course.

Re: Robot Arm B/C [Trial]

Posted: July 21st, 2011, 12:02 pm
by harryk
I'm also looking at lynxmotion basic stamp boards, they also sell some prebuilt robotic arm pieces that could be very useful, including a gripper that with some modification could be very well suited for this event

Re: Robot Arm B/C [Trial]

Posted: August 8th, 2011, 11:59 am
by twototwenty
harryk wrote:I've been reading up on programming and imagining design ideas, but I wouldn't suggest buying/building anything because the rules could be very different, though I've been playing with legos to test ideas
According to chalker 7 (see the 2011-2012 forum in general chat), the rules regarding the robot's construction and task are not being changed significantly, so it would be possible to start building over the summer.