It begins. Specifications for harvey:
Drive motors - 2 * 24 Volt 100 Watt Razor Scooter motors
Drive train - 2.5 : 1 HTD pulleys, four wheel drive
Batteries - GTL brand 2000 mAh LR123A, 6S1P
ESC - Sabertooth 2x12RC
TX / RX - HK-T6A-V2
Wheels - 82 mm rollerblade wheels.

Armour - 98% awesomeness, 5% testosterone.
Weapon - Spearhook, killer smile, phaser array (interchangeable)

I'm probably going to start off with a wire broom as an offensive shield and use the grunt of 200 watts to push opponents around. I'm designing the bot to be invertible, and may make it just a stepping stone to a better weapon / different design / whatever. I was looking around at home and I have a Pulsar about to be scrapped (wiper and fan motors) a DD turntable (large disk weapon) and another couple of motors from scooters and winches. AND I have some insanely big wheels off a bunch of kiddy cars and their attendant motors. So expect to see a few other clunkers out there after harvey.

Well, one or two things don't add up yet. To get four wheel drive I am going to buy some double sided timing belts, otherwise the convolutions in the belt will destroy it and rob so much power. Also, the 82 mm wheels don't give enough clearance for armour when running with a 68 mm diameter motor! So some 100 mm scooter wheels are on the way.

... but there's always plan B...

I'm using some of the ridiculous oversize kiddy car wheels with four 24 volt Canon motors. They're driving a pinion gear reducing by a 1:~6 ratio onto a 240 mm wheel, so if my calcs are right (and there is a risk with that) the no-load speed of the wheel periphery will be about 18 kph with my 2500 rpm motor. Of course, there is friction galore to take into account, so it'll be slower than that, but the speed figures previously given seemed to indicate from 15 to 20 kph was nippy enough. For a weapon, I was thinking of using one of the big motors running a mulcher / chipper blade. The mulcher isn't using it much Gotta fit it under the weight limit though, and I don't know how well the big plastic tyres will last against a nasty spinner or a flame weapon. I don't think I'll put terribly much effort into this one, just in case.

The Canon motor shafts are 4 mm, the bore of the pinion gears is 5 mm. A 40 mm strip of "V" can wound around the motor shaft makes an excellent collar to increase the shaft size. I just put a grub screw on each side and tightened them both: They run quite true.

Ripped some of the motors out of the Pulsar. The aircon radiator fan motor is only 35 mm thick but 95 mm across. It fair screams along. I think it'll make a fine spinning weapon motor, powering a ~3kg DD turntable platter. Maybe harvey can have some teeth after all.

Feather or Beetleweight?

And pictures?
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Steven Martin
Twisted Constructions
http://www.botbitz.com

Hi Kato
Sounds like a beast!.....Whats it like steering with the big wheels? If there is anything we have learnt from the last event, its that steering is probably the most important thing.

We noticed that it was easier for our robot to control with smaller roller blade wheels instead of the Bunnings red wheels. But we are using lame blue speedos.
miles
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Miles Blow - Julie Pitts
www.mulesfilm.com.au
www.wombokforest.com.au

-Pickasso- Vivid Sportsman champion 2015

Hopefully its a lightweight.
I need a purpose.

At this stage everything is featherweight. Sorry frogbiscuit. I don't have the fiscal resources to make a robot from unobtainium for the lighter weight divisions nor do I have the materials to make one big and strong enough for a lightweight class. I'm going with what I see in Brisbane - a good crop of feathers.

M&J, I have two of the blue speed controllers (three actually, but one is going in my Sand Scorcher ) and one Sabertooth. I will probably be making my own weapon switch, sort of like a cheap battleswitch, as I don't think the weapon needs precision speed control. I think harvey will get the Sabertooth, because it has the bigger motors. Plan B will get a pair of blue speedos.

Pictures? Not yet. Everything is just screwed to bits of wood ATM.

Handling is erratic with the big wheels, but it might be just us.

Does anyone else have a weapon that spins about the third axis - not the one used by Scissorhands (vertical axis) and not the one used by Demon (transverse axis), but the axis that points along the direction of travel?

Last edited by kato on Wed Feb 23, 2011 10:39 am; edited 1 time in total

Hmmm no but its sorta hard to hit someone with a weapon spinning about the X-axis. Can't exactly ram them with it.

With the blue speed controllers make sure that they are both running with forward being forward on the robot. Might help with controllability a bit.
_________________
Steven Martin
Twisted Constructions
http://www.botbitz.com

Mulcher blade looks like the nasty spinny bit at the bottom of a blender.

Hi Kato- sounds like you have quite a few esc options there!
You probably already done this ..... remember to pull out the red wires (running to the receiver) on your 2nd and 3rd blue speedos . Otherwise the power from each blue speedo might fry the receiver. Apparently anyway.
Miles
_________________
Miles Blow - Julie Pitts
www.mulesfilm.com.au
www.wombokforest.com.au

-Pickasso- Vivid Sportsman champion 2015

Any progress on this one? Event in 4 weeks....
_________________
Steven Martin
Twisted Constructions
http://www.botbitz.com

Sitting around waiting to find some spare money to do anything properly is just burning time. I watched all of the videos of the nationals and realized there are robots out there that are every bit as $#!+ as any robot I could make, so I'm going to start and just do it.

To that end I'm just going to make a rammer. It'll be invertible, 4WD, and will probably be just cannon fodder in the great robowars saga. And since I can't weld, and don't know anyone who can, and can't afford a welder, it'll be totally screwed, in more ways than one.

Well if you build something that drives reliably (before the event)...then you are 90% of way there,I reckon.

I picked my crappy old welder up on ebay for $40....but I know what having no spare cash is like
_________________
Miles Blow - Julie Pitts
www.mulesfilm.com.au
www.wombokforest.com.au

-Pickasso- Vivid Sportsman champion 2015

In my opinion, rocking up with a @#!$ robot is better than not rocking up at all. Due to being broke and having full time final semester uni, only had two days to smack a robot together, actually made a profit from the event. Will reinvest in better robot.
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