Weekend Project: Making Robot Frames Using Sturdy Solid Wire

Here's a fun weekend project creating a Buggy Bot robot base... Later we can add sensors to it, but for right now, it's a simple weekend project touting the benefits of using #12 wire to build bots...

From Making Robot ...

It's more research into building my upright RFL Football Robot! So far things are working pretty well, but I've got to work the pc board into the design, plus build a Cage around my bot, just in case I have to do battle.

Anyway, that got me thinking about wire as a base for the kinds of little bots I build around here, and very applicable to the RFL Football Bot (see March, this blog)...

From Making Robot ...

It looks like tying together rebar for pouring a cement foundation.

From Making Robot ...

Eventually, you solder the wires, then clip the excess, the solder holds the structure together, the wires help create the structure...

From Making Robot ...

The tabs have to be parallel to the axle, so you bend the wire appropriately...

From Making Robot ...

Now a top view

From Making Robot ...

From Making Robot ...

Dropping in the battery pack, so the switch is accessible while the bot runs...

From Making Robot ...

From Making Robot ...

Notice how the servo is held by bending a square around it, then tucking a piece of wire firmly against the servo... This makes the servo have a slight angle, but it is very strong... As you can see in the next photo...

From Making Robot ...

From Making Robot ...

Motor controller with picAxe 14m and a brand new Toshiba 1 amp motor driver (with dynamic breaking built-in... This thing is sweeeeeet! It uses two pins from the microprocessor to control the four operational modes: forward, reverse, stop, and brake... Very nice indeed.

From Making Robot ...

Soon (after the Pilot Test Run), I'd find out that it wouldn't steer because the front axle is fixed and what is transmitted to one wheel also goes to the other, this isn't good for making turns... In fact, with the batteries on the backend, there is som much weight I can't get the bot to steer at all...

The answer: Move the battery pack to shift the weight to the front wheels... as you can see in the next picture...

From Making Robot ...

The new shape of the weekend project bot!

From Making Robot ...

From the back....

From Making Robot ...

The side....

And, of course, like all good bot-builders and mashup dudes, here is the video: A step-by-step "weekend project" sure, it's about the wireframe idea for bot-bodies, but it's also all about this little Buggy-Bot...


Next stop for the Buggy Bot, get some sensors, so it can do object avoidance...

RFL Inspired Stand Up Bot Base Phase I Complete

Putting the picAxe 18x plus motor drive (same one as in dogbot) would be the bees knees... Except for one thing... The power! Oh the power! I used a simple turn right, turn left kind of approach for the initial testing and with one motor, then the other running, each would dig-in to the carpet, not really run along it...

Let's dig into the software and see what we can do to make our bot civilized, using it's brains to direct it's brawn....

The wheels came in the mail, they just push right on to the twin motor gearbox... I've got things taped and wired together, just to be sure this whole idea will work...

We're off...


These are seeming to be disasters... I got the new wheels, they provide better traction, but now the upright bot has falling over issues when it jumps forward or backward...

I figured I'd have to readjust things a bit... Then I got myself a handful of these grounding straps... These things are easy to bend and that allows me to clean up the design by bending brackets for the "shoulder pads." Now the batteries transfer their weight to the wheels by virtue of angled brackets that attach to the screws that hold the motor-body together. This works well...

From RFL Inspired ...

Things are working very well now, some tweaks to the new front stabilizing suspension and the picAxe 18x does it's job. We now have motor control... Check out the Final Motor Control and RFL Football Inspired Upright Bot Base Video...

Phase II Next Up... How 'bout some "eyes", some IR so this guy can either home in on an opponent, or avoid said opponent bot... Maybe I'm going to have to work that big frame back into the bot design? Stay Tuned...

RFL Football Type Robot

I get robot ideas from other robots... Like, I was inspired by some guy's robotic dog, that I started out to build dogBot... That was a great experience and spanned an exposure to both the 14m and 18x picAxe chips along with an H-Bridge, actually, two of 'em (one per wheel.)

Sparkfun.com sells these, that's where I saw them first, then in YouTube videos... These things are cool, so I'll take a whack at makin' my own, from my junkbox!

I love the RFL, sometimes called the Robot Football League, but really the Robot Fighting League - Football...

The bots run upright, powered by wheels, and not held upright with fancy inertial guidance system.

From RFL Inspired ...

Well, my junkbox has a limited number of parts in it, so I had to create a kind of "junk parts available" kind of approach.

From RFL Inspired ...

Then came the problem with mounting the batteries...

When the thing took off, it would over-drive its own wheels, and fall over...
After some unsuccessful attempts at attaining balance, I discovered you need the batteries to distribute their weight directly on the motors to maximize power transfer to the bot wheels...

From RFL Inspired ...

Finally, after some rework we have some motor drive that looks like it will make it...

From RFL Inspired ...

Blog entry, we find out whether our scheme works as planned by putting some tires on this bot and doing something about those front wheels, they keep unscrewing, they are entirely wrong for this application, but they are what I have in the junk box...

From RFL Inspired ...

It's a robot project, so here's the video of the motor testing, with a lot of the failures removed :-)



Next Time We Get Some Nicer Wheels (Come on Mailman!!!)...

From RFL Inspired ...

One last item... And it's a tricky one: Where to mount the batteries in our junkbox version...

From RFL Inspired ...

Why not divide the pack in two using two X 2-AA battery holders??? This would make the design more compact, lower the center of gravity... Something like this...

From RFL Inspired ...

The two 9-volt battery clip holders get mounted as a pair, they rest on flanges from the twin motor gearbox, so make a holder out of plastic and Voila!

From RFL Inspired ...

Woo Hoo! It works... Now the bot is not top-heavy, this should make it more powerful... And, it does:

From RFL Inspired ...

Check out the modified football player bot now---



Now we've got power to wheels, stability, and oh boy! is this gonna be fun.

Let's hookup the motor drivers and picAxe 18 and see what we've got!