• 200lb Robot
    16 replies, posted
I'm going to be rebuilding my old wheelchair-based ROV into something more awesome. Here's the plan: Remove all the essentials from the old 'bot. This includes motors/gearboxes/batteries/electronics. Fix up some old snowblower tracks. Build a new frame and mount everything in it in this configuration: [img_thumb]http://i.minus.com/i24kXbpYCFjoF.png[/img_thumb] Let's get started. After a few months of searching I found suitable tracks on Ebay and purchased them right away. The guy overcharged me on shipping but I was able to get the difference refunded. Both sets of tracks were covered in dirt and thick grease. (The picture makes them look much nicer than they were.) [img_thumb]http://i.minus.com/juGrF6UC0ZcoU.jpg[/img_thumb] One was in much worse condition than the other(chunks missing from treads, more rust, over-tightened bolts). I disassembled and cleaned the nicer one and purchased some Shoe Goo for tread repair. Here's the cleaned track unit with the motors/gearboxes and the batteries. [img_thumb]http://i.minus.com/jcYsED3YdbFx2.jpg[/img_thumb] I started on the repair of the worse tread. The other tread will need some repair too, but that's minor in comparison to this one. [img_thumb]http://i.minus.com/jbgQlN3XrBV3o2.jpg[/img_thumb] I'm basically going to have to rebuild the entire track out of Shoe Goo. I'm starting with a little bit to see how well it works. Questions/comments are welcome.
Hell yeah I love these kind of things. Will it do anything special, or will it just drive around?
[QUOTE=FreeBee;35647929]Hell yeah I love these kind of things. Will it do anything special, or will it just drive around?[/QUOTE] Current plans involve getting a wrt54g router. They have serial connection within the case and my motor controller can be driven through packetized serial input. The hope there is control over wifi rather than the 2.4ghz radio I had been using. After that, I want to get some form of camera set up with a low enough latency to allow for control through the camera. Most setups I've tried so far involving webcams and laptops have had a half second or higher latency which is way too much unless you like driving into walls. The best results in that area have come from a phone running Google Hangout which leads me to believe there is room for improvement. I also had a fully automatic Nerf blaster mounted to the last one which was amusing to say the least.
Autonomy! Make it autonomous!
Put a potato cannon on it: home-made mobile artillery robot
[QUOTE=Kwigg;35674111]Put a potato cannon on it: home-made mobile artillery robot[/QUOTE] I actually have an old fire extinguisher tank over in the corner that was saved for some form of potato cannon. Problem is finding a large enough electronic valve with a quick enough cycling time for less than absurd amounts of money. In other news, I spent the majority of today inhaling gasoline fumes while I cleaned all the grease off of the chains and sprockets. I also made a slightly annoying discovery. The previous owner of one of these treads decided, for whatever reason, to replace some of the bolts that hold in the axles with his own wrong size and wrong thread-count bolts making it insanely difficult to remove them without a vice or other device to clamp the axle in place. On the plus side, covering the messed up tread in Shoe Goo seems to be going well. I can only do it in roughly 10" sections at a time though, so it's going to take awhile to cover the entire thing.
Sounds like you got severely cheated on those treads. I would definitely give the seller negative feedback and see if Ebay can do anything about it for you.
put something on it that releases a visible burst of gas upon radio command (to make people flip the fuck out)
Sorry for the lack of updates. I've been trying to work out the best method to go from a 17mm shaft(the motors) to a 3/4" shaft(the sprockets).I've exhausted just about every part supplier and every combination of parts and nobody has anything that would work without significant machining. I ordered a few parts from McMaster-Carr and I hope to jury rig a solution from them. In the mean time I threw together a frame design in Hammer. [img_thumb]http://i.minus.com/innNf1dGxesZZ.PNG[/img_thumb] My original design was much simpler but it relied on a 13"x14"x1/4" steel plate which is very expensive. This design uses 3/4" square steel tubing and 3/4" angle iron as supports. I don't have access to welding equipment so I'll be assembling the frame with careful application of very large quantities of JB Weld. :v:
Re-hosted all the images on something other than imgur. Also I wasn't joking about the covering the tracks in Shoe Goo. [img_thumb]http://i.minus.com/iXlDN5Lnegw1H.jpg[/img_thumb]
Quick update: I received the stuff I ordered from McMaster-Carr yesterday. I was able to get the couplings machined properly and now I need to do some hand machining to get the sprocket shafts to the proper diameter.
Warning, unsafe practices below. Do NOT try at home. I don't have a lathe sitting around here so I had to settle for a scooter motor and some couplings. [img_thumb]http://i.minus.com/ijQIB49lrUYqD.jpg[/img_thumb] The shoe is for vibration dampening and the plastic piece is a bushing that allows me to hold the shaft as I work on it. [img_thumb]http://i.minus.com/iLgXri7jRZlZ3.jpg[/img_thumb] The top sprocket/shaft thing is what I started with. [img_thumb]http://i.minus.com/i1YGvMfAqe88M.jpg[/img_thumb] Not bad for manual work, if I do say so myself. Need to cut the shaft to length still and repeat the process with the other one. I'm going to run out to Ace now to grab some longer set screws.
Genius! That looks pretty rad from such a setup, lol.
[QUOTE=FreeBee;35808523]Genius! That looks pretty rad from such a setup, lol.[/QUOTE] Thanks. I cut down a set screw to fit into the key-way on the motor/gearbox shaft. [img_thumb]http://i.minus.com/itWFzGlRWazsf.jpg[/img_thumb] [img_thumb]http://i.minus.com/ibvDVitdP3xoDb.jpg[/img_thumb] Here's all the pieces for the required to mount the right sprocket. I used a Dremel to make dimple in the shaft so that the set screw on the coupling would have something to catch on. [img_thumb]http://i.minus.com/izJxPPjUd2l8D.jpg[/img_thumb] Here's the above, but assembled. Now I need to do it all again for the other motor.
Just got some steel stock and JB-Weld. I've greatly simplified the frame design at the expense of weight distribution. It's going to be a little back heavy but I'm cutting my frame costs by 2/3 and saving a bunch of time. It makes use of 1" square tubing and 1 1/2" angle iron. [img_thumb]http://i.minus.com/ibh2LGugEa4hEA.PNG[/img_thumb] On a related note, cutting steel with a hacksaw takes awhile. Normally I'd use a Dremel but I don't think my neighbors would appreciate the noise.
If you think the noise would bother them, you should do it at night. Probably between midnight and five in the morning. That way they're asleep when you do it and they can't hear it.
[QUOTE=AlarinTaylor;35799096][img_thumb]http://i.minus.com/ijQIB49lrUYqD.jpg[/img_thumb][/QUOTE] Never use a file like that without a handle. Unless of course you want the file in-bedded in your arm by its tang. The handles for them are pretty cheap.
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