Let's Make Robots!


Navigates via Ultrasound, annoys the dogs

2012/12/4-Yay, the video is working!

Also, OddBot is right, it is called "BubbleBot" because it is full of air, though I don't know how hot it was.

This is the most complete robot I've ever made.  That's because I intentionally killed it right after I made the video:

I was so sick of this thing that I did what anyone would do: I stuck an X-acto knife in his head.

BubbleBot started life as an RC Car:

I saw it at the local big-box contractor-grade hardware store for a bit over U$11.00.  Cheap RC toys always catch my eye, but this one was a unicorn; it has something that you never see on RC toys anymore:

That's right:differential drive.

The hack was fairly straight forward.  Open it up, lobotomize it, save the RC unit, run wires out of the housing to the motors and the battery compartment and attach them to new brains taped to the top.

The brains are pretty straightforward too.  A single ultrasonic sensor on an Arduino Mega (overkill) pushing a Hex L298d motor board (I love those things-cheap, ready made and they just work like they're supposed to.)

The program was about as simple as it could be.  The loop drives the unit forward unless it detects an obstacle at about 30 cm and then turns right.  It has no contact sensors so it can get stuck on corners easily.  It doesn't run on carpet very well and it's kind of like a pillow on wheels.

Anyway, now it's dead.  The real reason I purchased it was to get the easy differential drive unit for cheap.  The great thing about these kinds of units is that the motors are usually matched really well because the h-bridges in their RC receivers tend to be hugely oversimplified, lacking a speed-controlled enable or any method (like encoders) of knowing if one wheel is spinning faster than the other.  I just set both PWMs on the h-bridge to the same level and got a relatively straight line out of it.

Still, I took great pleasure in killing it that way.

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Robot assassination will one day be a crime Max.  I would erase the evidence before you are hauled up before the Robotic Court of Justice...LOL.

But anyone would kill for that nice diff drive unit.

I think I know what Bubble Bot's problem was... he was full of hot air!

Maybe I am overinflating the problem?


Very nice! I should have put more plays-on-words into this. For shame, I wasn't more creative. ;-)