found new six legged robot in progress, maybe someone interested...

http://max.hm2003.nl

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STUNNING!

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Could you tell what motors and power supply you use? Also approximate maximum weight (inclusign load) of the robot?
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Ek wrote:

If you scroll down the page, you'll see what look like some standard gearmotors, GH3x or 38GM variety. It's a beautiful machined design, but must weigh a lot, 20-30# or more, not including batteries. Hard to know what battery it could lift that could power it for very long. This is "the" big problem with walkers, weight vs power source. I've built 3 walkers now, and this is the biggest issue. My octopod has 16 servos, and one thin 12"x12" aluminum plate for a body, and it weighs almost 5#, by time you put the legs, controller, batteries, etc, on it. - dan michaels www.oricomtech.com =====================
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It does look over built, but certainly well built.
Mike

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blueeyedpop wrote:

Well built, that's for sure. Sadly, all my robots are built by drill press, hack saw, and file, and I'm always envious of those guys with milling machines. OTOH, it's taught me to go simple, cheap, and lightweight. Makes for happy servos.
- dan ==========

standard
but
know
is
3
servos,
almost
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I made the mistake making my first robot too powerful requiring two car batteries and heavy duty H-bridge control. The main reason was because I was going to use a PC tower as a "brain". It was strong enough to push a couch around the room, smash glass doors and burn rubber if stopped by a wall and the touch sensor failed!
The *much* cheaper, and safer for little kids and stray cats, is a light weight robot connected via wireless to the PC.
I have never built a walking robot. Not sure how the wife would take to an oversized mechanical spider wandering down the passage :) -john
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snipped-for-privacy@yahoo.com.au wrote:

car batteries and heavy duty H-bridge control. The main reason was> because I was going to use a PC tower as a "brain". It was strong> enough to push a couch around the room, smash glass doors and> burn rubber if stopped by a wall and the touch sensor failed!

light> weight robot connected via wireless to the PC.

to an oversized mechanical spider wandering down the passage :)

My octopod is 12"x12", and some think it's scary looking. All those moving legs, I guess. The new quadruped is only 6"x6". 27 oz [760 gm] in the quad, versus 80 oz [2200 gm] in the octopod, and they use the same batteries - AA cells. I don't think the big aluminum jobber http://max.hm2003.nl/ can get away with that.
[BTW, when you hit reply, a link appears where you can go to change your nickname - you asked about that].
- dan =========
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I can sometimes beg-borrow-scrounge mill and lathe work, but mostly I use filener.com for my laser cut polycarb. Light, tough, precise, cheap.
Mike
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I got to thinking about this super hexapod. It looks like three gear motors per leg, six legs, makes up 18 gear motors. So you have 18 h-bridge motor controllers, plus extra h-bridges for the head and stuff too. If those are the small gear motors I think they are (12v GHx's), they draw about 1.5 amps each under load for a total of 27 amps max. If the gear ratios and such are right then if you use locked anti-phase to hold the positions, you would probably have around 500ma for 18 of the motors on a level surface holding the position and standung needing 9 amps or so. Granted only 12 of the motors are under load holding it up, but locked antiphase tends to suck power in the holding locked position (50% duty cycle). A bunch of sub-c Nicads would work well (not NMH), or a big gel-cell is even more likely. A 7 to 12ah gell cell is probably good for about 30 minutes or so. But in looking at the robot, it does appear that it is externally powered by a long power cable. The banana plugs on the bottom. The original that they modelled from is externally powered. A 30 amp AC-DC 12v or 24v power supply is still pretty spectacular no matter if you buy or build it.
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I was thinking small gasoline powered generator... LiPoly May do it, with a separate power circuit per leg.
Though curious why not NiMH?
Mike
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Perhaps the time has come for steam - a flash steam boiler doesn't weigh very much, and in many respects steam has the advantages of pneumatics. Besides, think what the cat would do !

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: Perhaps the time has come for steam - a flash steam boiler doesn't weigh : very much, and in many respects steam has the advantages of pneumatics. : Besides, think what the cat would do !     --Funny you should mention this; my first Stamp project ran on pneumatics; it's a small step from there to steam. All that's required are solenoid valves with "high temp" wiring; i.e. there's a price hike of maybe 10 to 20% over the standard variety, then you're in business. I'm working on a Stamp controlled steam calliope, heh.
--
"Steamboat Ed" Haas : Somehow related
Hacking the Trailing Edge! : to Lumpy Adams...
  Click to see the full signature.
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NMH cells have a higher internal resistance and can't provide the high current levels like Nicads can. But if one runs several NMH packs, it might work. Although if they are using 12v motors one large 12v pack may weigh less though.
A small gas generator might work though, that is a good idea. :) One of those little Colman generators would just work great. It would need 300 to 500 watts though. A jillion years ago in the prehistoric computer era, we had a small tiny 200w gas generator in the Marine Corps. It was used to power some kind of a HF radio that no one had anymore, But we still had to keep the little generator around on the books. It had a little, maybe 40cc 2 cycle engine and a little generator in a really small compact unit. We used to use it to power a bread toaster of all things. One of those little luxuries from home. :) All my life I looked for one of those suckers surplus, but never found one.
You know, I got some of those evil 220v DC small Johnson motors. If I get the chance, I'll have to see how much voltage and power I can get out of one when I spin it up sometime. :) If it works Ok, it just might make for a nice gas generator, if I can find a really small gas engine to go with it (not a RC model alcohol engine). Of course it would be an outdoor only system as indoors the carbon monoxide and fumes would be intolerable. But that is a really good idea.
wrote:

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How about Diesel? http://www.justengines.unseen.org/paw.htm 0.55 cc to 10 cc
wrote:

two>
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gasoline engines, diesel, steam turbines, I remember once reading about a 20' high robo-dinosaur that used a V8 engine ... sometimes I wonder if this isn't the tail wagging the dog a bit. OTOH, a coupla years ago they had the ASME walking machine contest nearby, and the coolest bots [200-300# big boys] were using pneumatics, but most used dual cartesian-table designs to handle the weight. OTOH, I have one smallish walker on the drawing board with a foam body [kind used in those flying wings]. Should cut the weight down a tad over aluminium frame. fast, cheap, and out [as in void] of aluminum.
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What are the really neatest things are the model turbine jet engines like these. http://www.diynet.com/diy/rc_planes_aircraft/article/0,2033,DIY_14224_2490260,00.html But they are pretty noisy. The small model RC diesel engines on the other hand, are amazingly quiet, you almost can't tell when they are running.

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    --Speaking of pneumatics, etc check out Trevor's latest here: http://anybots.com/latest.html
--
"Steamboat Ed" Haas : Somehow related
Hacking the Trailing Edge! : to Lumpy Adams...
  Click to see the full signature.
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gasoline engines, diesel, steam turbines, I remember once reading about a 20' high robo-dinosaur that used a V8 engine ... sometimes I wonder if this isn't the tail wagging the dog a bit. OTOH, a coupla years ago they had the ASME walking machine contest nearby, and the coolest bots [200-300# big boys] were using pneumatics, but most used dual cartesian-table designs to handle the weight. OTOH, I have one smallish walker on the drawing board with a foam body [kind used in those flying wings]. Should cut the weight down a tad over aluminium frame. fast, cheap, and out [as in void] of aluminum.
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Diesels would work pretty good, but the fuel is a bit tricky, definitely outdoors only. Typical fuel as recommended by PAW is 20% castor oil, 48% parrifin, 30% ether, and 2% IsoPropylNitrate. It is sure hard to keep the ether from evaporating. Many years ago, I used to use castor oil, kerosene and lots of ether, but no nitro. Way back then there were only a few companies that made diesel engines,and adapters for regular RC model glow engines. So those of us that had diesels were pretty much on our own. A diesel would be a pretty good idea, but the fuel has to be handled carefully.
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