RoboSavvy Forum

Wanna fight?

2006-09-23T15:02:51+01:00

Holy scary! 8O They're gonna' have to create a new class for 'em... Robo-One meets Combat ROV's!

Statistics: Posted by bauermech — Sat Sep 23, 2006 3:02 pm

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2006-09-22T23:39:31+01:00

Yeah,
Robot - cutdown those pumps!
That'll keep her in line. Do you leave your robot on running sentry duty when your not home

Statistics: Posted by Bullit — Fri Sep 22, 2006 11:39 pm

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2006-09-22T23:35:29+01:00

She never was taller you scoundrel, and she's losing a few inches of what were once considered legs but are now generally called 'stumps' every day.

Statistics: Posted by beermat — Fri Sep 22, 2006 11:35 pm

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2006-09-22T02:30:00+01:00

So, how tall was she before... I figure your robot could probably get her at the ankles... and, say it, come on, say it, she was taller than you wasnt she?

Statistics: Posted by hivemind — Fri Sep 22, 2006 2:30 am

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2006-09-22T01:19:30+01:00

Gotcha! I have the same concerns. At the speed it is spinning right now, current draw is less than 100mA, so I'm safe. That will increase at a higher spin rate and/or with some resistance when I start cutting things, at which point I was going to move onto a different method of motor control, along the lines of things you have previously mentioned. Right now, though, it's still fun to have the fiance freak out about it as it is!

Statistics: Posted by beermat — Fri Sep 22, 2006 1:19 am

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2006-09-21T02:15:51+01:00

The PWM's are putting out current from the mr-c3024's onboard regulator which is something like 350ma total. I think that they intend that you will use this output to drive a transistor which will switch the battery rail to a dc motor. You can make a small circuit with a few components to do this. My concerns are that you will either damage the ATMega128 or the regulator without a transistor to handle the load of a motor. The up side is that switching the battery rail you can put more voltage and power to a motor.

Statistics: Posted by Bullit — Thu Sep 21, 2006 2:15 am

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2006-09-21T00:58:31+01:00

Bullit, what is your main concern about going directly from the PWM port without using an ESC? PWM for DC motor control is not new, though it's a bit primitive? Various documentation on the MR-C3024 mentions the 3 DC motor ports. Am I mis-understanding something? The need for a BEC, for instance?

Statistics: Posted by beermat — Thu Sep 21, 2006 12:58 am

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2006-09-20T20:45:48+01:00

You say you have the motor powered by the pwm port? Or do you mean you have a rc speed controller that is connected to a pwm or servo port? I would think powering the motor off the pwm port could be bad. I would think that an r/c speed controller could be placed on any of the servo ports or the pwm port.

Statistics: Posted by Bullit — Wed Sep 20, 2006 8:45 pm

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2006-09-20T16:37:54+01:00

h3dude - the motor is a 'pancake' electric motor about 1.5" in diameter. I have it powered from PWM port 1, with a resistor in series to limit current draw (mostly concerned with stall current if he falls over). The motor shaft is 2mm, the hole in the center of the blade is 11mm, but I discovered a propeller shaft adapter for electric R/C planes designed for mounting things with big holes onto small shafts. Oooeerr missus.

Pev - interesting point. I haven't had him move around too much yet (wooden floors + spinning metal blade = night on the couch), but I'll play around later on a foam mat, see what happens. I definately 'felt' the push-back/resistance from the spinning blade when holding him and tilting him, so there is definately a gyroscopic effect here that is more than negligable. Section 2.8 of this article I just Googled is relevant to this topic.

Statistics: Posted by beermat — Wed Sep 20, 2006 4:37 pm

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2006-09-20T11:17:07+01:00

Awesome, but I have to ask, does it help him stay upright? I was thinking in a newtonian manner as a spinning disc will act like the gyroscopes we had as kids and will always try to maintain an upright position, or atleast maintain the orientation that they were originally spung up in. (hope I am remembering my school physics correctly it has been a long long time lol)

Anyway would be interested to know what effect it has if any

Pev

Statistics: Posted by Pev — Wed Sep 20, 2006 11:17 am

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2006-09-20T05:24:14+01:00

Holy crap man, you could seriously hurt someone/thing with that. I love it

What pins do you have the motor leads connected to? Also, what kind of motor is that?

Statistics: Posted by H3dude — Wed Sep 20, 2006 5:24 am

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2006-09-20T02:56:20+01:00

That is pretty sweet man, awesome work, nice aluminum bracket. The saw blade looks like a great killing machine. I'd love to see some more videos of that thing in action!

Statistics: Posted by hivemind — Wed Sep 20, 2006 2:56 am

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2006-09-20T01:37:22+01:00

Wanna take me? See video here

Statistics: Posted by beermat — Wed Sep 20, 2006 1:37 am