Flexing Vex

[Matt Krass]

I find it rather vexing that I seem to require flexing to make my Vex kit do anything impressing.

Ok now that I got that out of my system...

I'm loving my new Vex kit, built the SquareBot, tormented my cat, now I'm ready to build something of my own creation...but...

The only structural material left over is a few long strips of metal, and a few long strips of angle beam, and it seems rather difficult to turn that in to all these creations I see online.

So, How flexible is the material? Can I bend it repeatedly without wearing it out too rapidly? What about about cutting it? Does anybody ever use it in it's full length and if not, any recommendations what sizes I should cut it down to?

Should I look in to the extra materials pack? (I heard it's about $70, a little steep for me to just grab..)

In short, just how much can I do to the Vex base kit and can someone show me some examples of reasonably complex robots using nothing but starter kit parts?

[foobert]

Originally Posted by Matt Krass

I find it rather vexing that I seem to require flexing to make my Vex kit do anything impressing.

Ok now that I got that out of my system...

I'm loving my new Vex kit, built the SquareBot, tormented my cat, now I'm ready to build something of my own creation...but...

The only structural material left over is a few long strips of metal, and a few long strips of angle beam, and it seems rather difficult to turn that in to all these creations I see online.

So, How flexible is the material? Can I bend it repeatedly without wearing it out too rapidly? What about about cutting it? Does anybody ever use it in it's full length and if not, any recommendations what sizes I should cut it down to?

Should I look in to the extra materials pack? (I heard it's about $70, a little steep for me to just grab..)

In short, just how much can I do to the Vex base kit and can someone show me some examples of reasonably complex robots using nothing but starter kit parts?

check out http://www.vexlabs.com/vex-robot-photos.shtml. some of these robots were built with little more than the vex kit. some required an additional motor, gear, or wheel from an accessory pack. i think one used the tank tread kit.

also, i think the twin tweaks column in the july issue of servo magazine features a ball collecting 'bot built using nothing but the base kit. some irreversible modifications to some parts were made.

me, i just got the programming kit and have enjoyed adding various sensors and leds to the square bot.

before i got the programming kit i soldered a resistor to one leg of an led and plugged it into a motor output so its brightness varied with the stick position.

[petek]

Originally Posted by Matt Krass

So, How flexible is the material? Can I bend it repeatedly without wearing it out too rapidly? What about about cutting it? Does anybody ever use it in it's full length and if not, any recommendations what sizes I should cut it down to?

The stuff they used appears to be zinc-plated mild steel, which can be bent to shape. I recommend bending it with a minimum bend radius = .025 in (half the material thickness). All the pieces are .050 stock except the "panel", which is .032.

Like most metals, you should avoid re-bending as that would weaken it a lot. Most likely you've tried flexing a piece of metal or plastic back and forth to break it off - each time you bend it it weakens it more. This is sometimes called "fatigue".

Should I look in to the extra materials pack? (I heard it's about $70, a little steep for me to just grab..)

Yikes! You're right: Metal and Hardware Kit $79.99 (- 10% edu. discount) How perplexing!

I'm at about the same point - I've done the Squarebot, chased the dog, started up Easy C and run the Online Code to check out the I/O. Next I think I'm going to look into what speed the Vex should be capable of. I need more speed to keep up with the dog! JVN posted the approx. speed and torque for the motor which I'll plug into his Mechanical Design Calculator and see what happens.

[artdutra04]

Originally Posted by petek

Yikes! You're right: Metal and Hardware Kit $79.99 (= 10% edu. discount) How perplexing!

I know the expansion kits are somewhat expensive, but you get what you pay for. The four most valuable expansion kits that you can buy are an additional Vex Motor, the Vex Hardware Kit, the Vex Chain and Sprocket Kit, and the Vex Programming Module. With these, you can create almost any kind of Vex robot that you can imagine. Minus the Programming module, these were the four basic expansion kits that it took to create my Vex robot.

[sanddrag]

I'm not sure how fancy you want to get but you can make some inexpensive, very nice looking and pretty darn strong frames with 3/16" diameter brass tubing, a little bit of brass plate (for mounting locations), a dremel tool, some solder, a high wattage soldering iron, and some time and patience. Here's one I did: http://www.chiefdelphi.com/forums/pi...le&picid=11732

Here's another example: http://www.truckworld.com/Monster-Tr...tubeframe.html

Just be sure to clean the oxidation with something like 400 grit sandpaper just before you solder it. Also, notching the tubes with a dremel so they fit together is a really good idea.

I recommend building the flat (2d) sections on a pice of board that you can put push pins (T pins) into to hold the pieces in place while you solder one side, then flip it over and re-pin it and solder the other side. The technique of laying out the parts over the plan and holding them in place with pins is somewhat similar to building parts of a balsa wood model airplane or a wood bridge.

[mechanicalbrain]

I think that a robot with and significant flexability will involve the implementation of segments. Here is an example of what im thinking about http://www.robotstore.com/catalog/display.asp?pid=717 . But what are you looking for? Is it going to be long, short, flexible over one or two axis? Overall I wouldn't recomend bending anything, Why not just use joints?

[jeffmorris]

You can use other materials to build robots. The steel pieces can be bent, cut, and drilled. Any suggestions for a cheap but strong metal bending machine?

[JVN]

Originally Posted by Matt Krass

I find it rather vexing that I seem to require flexing to make my Vex kit do anything impressing.

Ok now that I got that out of my system...

I'm loving my new Vex kit, built the SquareBot, tormented my cat, now I'm ready to build something of my own creation...but...

The only structural material left over is a few long strips of metal, and a few long strips of angle beam, and it seems rather difficult to turn that in to all these creations I see online.

So, How flexible is the material? Can I bend it repeatedly without wearing it out too rapidly? What about about cutting it? Does anybody ever use it in it's full length and if not, any recommendations what sizes I should cut it down to?

Should I look in to the extra materials pack? (I heard it's about $70, a little steep for me to just grab..)

In short, just how much can I do to the Vex base kit and can someone show me some examples of reasonably complex robots using nothing but starter kit parts?

Matt,
Glad to see you've taken the Vex plunge. It is an exciting kit to play with.

The material will fatigue if you bend/rebend repeatedly.
Also, you're going to start having problems getting to the shape you want. (It's not easy to re-flatten that stuff. )

Some of the metal pieces are designed to be consumable materials.
Bend/Cut as needed for each application. However, if this isn't possible - you need to do whatever your budget dictates.

The Vex Metal/Hardware pack is great, it contains all the metal pieces and hardware that comes in a starter kit; it also contains more bearings, shaft, shaftcollars and other motion pieces.

Soon, VexLABS will be offering some additional metal pieces and kits at different levels of cost. (i.e. if the $80 bundle is too much for you, we may have a $40 bundle.) Stay tuned.

John

[Matt Krass]

Thanks for the replies everyone, I'll be uploading pics of my new Vex Tetra capper with the mini-tetras my girlfriend made out of drinking straws soon.