DIY Giant RC Spider.

[HibLaGrande]

OK, so here is my idea, I will need as much help as I can get for this one.:D

A Giant RC Spider!!!!
I have thought about this for years A big hairy spider that could chase people down the street or pop out of my neighbors hedge row all at the touch of a button. It was only when I started doing the actual research that I knew I was in over my head.

I have 2 12/DC motors from a powerwheels kids car that I would like to use. I would like these motors (one for each side) geared down to turn a cam for the legs and and to also run the drive wheels. I would like to run both of these motors off of a motorcycle battery/ies. And I would like it to be controled like a tank 2CH left side forward/reverse right side forward/reverse.

Has anyone found a way of mounting these motors??? they are really odd shaped, the drive shaft(tube?) is screwy too.

What kind of RC stuff should I be looking for. (I know zilch about the RC world ) other than I need a transmiter and reciver and motor controls of some sort.Also, I am cheap so any help in finding the stuff I need cheap wold be greatly appreciated.

[maxcarnage]

finally, somethin I can help with :)

you'r biggest enemy in the cost department is going to be the amperage you're going to be pulling. Most over the counter esc's (electronic speed controls) aren't going to be able to handle it without dying. This pretty much leaves you with 2 options....home build a mechanical sc, or buy a nice esc....one is obviously going to be alot cheaper than the other....if you decide to build your own you would just need the transmitter, reciever, 2 channel reciever that matches the transmitter, a couple of servos, and four leaf switches rated to the stall amperage the motor is going to have to pull, a couple of fuses would be a good idea too....as well as something to putt it all on. Another huge disadvantage would be trying to make it walk correctly....if it were me, I would just build it so it drove on specially made "wheels" so it would shuffle, then try and animate the spider so it appeared to be walking.....it'll be alot easier to build, as well as probably faster, and more reliable. As for the motor mounting and such, I would be more than happy to help you design something, but I would have to see a picture of the assembly, and possibly a couple of measurements .

I have tinkered with "robots" before, and still have a small library of literature on the subject, I would really like to see somebody make something like this, so if you need any help with anything, just shoot. I'll be glad to help any way I can.

[DeathTouch]

You are in luck. I have been thinking about this for while, and I know what you can do Instead of going with a RC car, how about getting a power wheels car and taking the motors and battery out of that thing to make your spider. Those cars are powerfully. Most of them can carry two kids. That means you can make a big spider and have him go around the yard. But, I would suggest making a track for him like train. Have him go around the grave yard. That might look cool.

[HibLaGrande]

I have 2 motors from powerwheels car,
And the legs are for effect not locomotion.and won't actually touch the ground. I was going to use Bicycle wheels for the drive wheels. I f I could make this thing sturdy enough to ride it would be cool. "Spider rides 1 dollar!":D

[maxcarnage]

it should be easy enough to do then....you should have enough power there with two motors to easily haul around a bit of weight...just make sure the motors will have plenty of juice. another interesting thing is that you can double up the voltage you use on these motors....it'll double the rpm's, but most importantly, it nearly quadruples the power output. but doing that also creates more heat on the motor, so you'd want to use some kind of small fans for cooling. would it be able to haul around an adult?....yes. Would it b cool?.....doubtless. If you need any technical assistance, just give me a shout, and I'll be glad to help however I can.

[HibLaGrande]

Here are a few pics of the motors I was thinking about using.
http://i12.photobucket.com/albums/a228/HibLaGrande/PA160015.jpg
http://i12.photobucket.com/albums/a228/HibLaGrande/PA160016.jpg

they are about -5-6 inches wide and about 9-10 inches tall. When I find one of my tape measure I will have a little more info. Ill have a better photo shop picture soon with some measurements drawn on it. I was thinking of drilling out the factory screw mounts and running longer bolts through it, sandwiching the plastic assembly between sheet metal.

I need to mention that only the white part spins. the black inner hub does not.

[HibLaGrande]

A mechanical sevo controled motor control set up would be mostlikly cheaper and plausable for me to build. I only worry about it sticking and running over someone. This thing is only going to move at a slow walking pace.

Doubling the power might eat up the nylon gears inside the assembly. so i dont' know?

any good sources for used rc kits? Ive checked on ebay and really don't know what to be looking for. I would like a 2 ch dual joystick type radio A compatible reciever and matching servos. and does not need a very long range. I looked at some rc toys at the store for possible canibalisation but came up empty handed.these wont handle the juice,

[maxcarnage]

no problem...I've done enough hobby level rc to help you put a budget friendly radio/reciever/ and servo combo together...

you are going to have a range of right around a hundred feet given you don't run into alot of interference with am stuff....cheaper

with fm stuff you can increase the range, as well as less chance of interference....but at a cost, fm stuff isn't cheap.

you're also currect in the assumption that the extra power might very well strip out the nylon gears, it is a very real possibility, so you're probably not going to want to double the voltage there.

here's an example of en ebay item you'll want to look for for the giant rc spider project http://cgi.ebay.com/Futaba-ATTACK-2-Channel_W0QQitemZ6005405776QQcategoryZ34063QQssPag eNameZWDVWQQrdZ1QQcmdZViewItem

[DeathTouch]

I have known people to get the power wheels things to work. Let me she show you how it was done. Check pictures down below.

http://cr.planetchristmas.com/default.asp?action=9&read=12012&fid=93

[maxcarnage]

I found a site for ya, that explains with pictures and wiring diagrams, some of the various ways to build a mechanical speed controller....

http://www.rctankcombat.com/articles/speed-control/

[HibLaGrande]

Thanks for the info Max,
here is my first attempt at 3d modeling. I made a gif. it is 1.6 megs (I forgot to shrink it down some) that shows the basic mechanics that I am hoping to attempt. The size is 2ftX2ft and is pretty close to scale.

BLACK Motor assembly.
YELLOW pulleys 2 8-inch 2 2inch
RED Drive axels (not to scale)
BLUE Bevel gears(not to scale)
WHITE PVC Leg assembly

http://i12.photobucket.com/albums/a228/HibLaGrande/spidermech.gif

[maxcarnage]

no problem...just glad I can help out a bit...the model looks great, I'd say you've got a pretty good handle on what you want to build.

[shaunathan]

Now you realize, being the first in the community to build such a prop, it's up to you to take LOTS of pictures and write the How-To, that way next year we can say "I'm building a Hibla RC spider."

[DeathTouch]

What modeling program are you using?

[HibLaGrande]

What modeling program are you using?

GMax it's free! Great program..! people use it to make their own 3d models for video games and stuff.I'm flying blind with this program. but slowly figuring it out. WAY Fun! I think you can download it from here [http://www.turbosquid.com/gmax was freeware!

[HibLaGrande]

Ok so after a little more thought I have decided not to go with the 12V power wheels motors. If I am going to spend all my time on this thing I dont want to base it around motors that are shaped goofy and hard to replace. I think that a more accessable motor would be a better way to go. I'm thinking electric wheelchair motors or something along that line.

I had seen a DC motor control switch kit online somewhere .I cant find it now, that controled forward and reverse with a POT. I'm not sure what the range of motion was for the POT.

Are there any good places to look for standardised gear sets? Im looking for steel or aluminum worm gear set to fit 1/2 in sloted axel rod. I think it would be more effecient and durable than the original bevel gears I had thought of first.

[maxcarnage]

actually, they're not.....most of the time worm gears are alot more fragile, and often do not tolerate reversing well

try here...you'd be suprised what you can find at one place :)
http://www.mcmaster.com/

[HibLaGrande]

WOW! all kinds of....Stuff. thanks for the link. Yeah after some research I found that the worms have a very low effeicency. With all the stuff at that site it really opens up some options.