Let's Make Robots!

Terd-L

Follows hands/shadows, avoids shadows...

Terd-L, for Two-Eyed Robotic Differential-Locomotion. (I can't believe I forgot to include that right away. May St. Markief forrgive me!)

Update 24 April 2013

Finally added the video.  It shows Terd in both "Follow Me" and "RunAway" modes.  I can actually switch the jumpers without tearing off his "shell," but I need needle nose pliers to get in under there and do it!  (Extra points if you recognize the music & know why I picked it!)

When I first started planning my entry into the "Diamond Mine" challenge, my idea was to make a Pakbot-style machine with an arm and a camera that I could pilot from a few meters away and use to pick up some chunks of glass.  To that end, I bought a bunch of parts, including a vintage Radio Shack/Tomy "Armatron Mobile" robot arm that was advertised as "whining but not working" or something like that.  I figured I could rig it well enough to get it to function.  In any case, I had too many sick days to complete the project and wound up with a bench full of parts to use for something else.

The base though was a differential drive that I hadn't been planning to use in the Diamond Mine Challenge, so I knew it could go to something else from the start.  

No disappointment there!  Picking up on the "research" I did with "Leela" I decided to do a slightly more controllable and toy-like machine.  It's essentially the same thing with two LDR/voltage dividers instead of one, so the robot kind of follows a hand if it's placed over either "eye."  

I was inspired by a couple of other recent LMRbots to make a body for it out of a Dollar-store mixing bowl, and just because I was bored I added the Larson Scanner.  The color scheme (yellow LEDS on Cardinal red) is there to honor my Alma-mader Iowa State University, which is held by SCOTUS to be the birthplace of the first Electronic Digital Computer in the US. (Actually, that's only kind of true-I just had a lot of yellow LEDs to use and I thought the red bowl would show up better in the little front-page photograph.)

The Larson Scanner ("Cylon Eye") uses an ATTiny 45, so saying it doesn't have a brain is a little misleading, but it's only using that microcontroller for bling.  All the mechatronic decision making is strictly "Analog Computing."

I experimented briefly with trying to invert the signals from the "eyes" to give the bot a zero-turn radius, but wasn't able to get satisfactory results.  My plan was to do this on either side:

...it didn't work with the pre-made L298 module though.   I even tried it with discrete component inverters (both a 74ac14 and a ULN2803) but to no avail. Something about these L298 modules doesn't like the janky signal modulation. It would have been nice-I could have added bump-switches so that when it hit an object it could turn until it escaped, but again, I kind of hit a wall of my own (the wall of losing interest in a project.)

One thing I did do was put the LDRs on Dupont terminals so that I can switch modes from shadow chaser to shadow-phobe, just by reversing which "eye" links to which side.

So what I'm left with is a fun-looking project that I might give to my nephew as a birthday present.  This is probably the last of the "brainless bots" that I'll experiment with for a while though.  Until I get another brilliant idea that I haven't seen someone else build there's really no point.  I know I can make amusing toys satisfactorily-I need to move on to making useful tools.

(I'll add video later-after this has been on the front page for a while and a few other posts have knocked it down a place or two! ;-)

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Oh this is adorable Max, I see you have been doing some interesting things here.  Perhaps this is Cylon model -6?  It has a way to go to catch up to the blonde, but I like it anyway ...LOL.

Silly name and fun looks make an interesting build. I never thought of messing with an h bridge like that! Good info. Yet another simple but entertaining bot from the Max. Stephen (Goes off looking for old Tupperware in the kitchen...)
CP and I are going to get all the married guys in trouble with their wives!

You guys can't get me in trouble with my wife - I'm never out of it :)

 :D Mwuahahaha

"I was inspired by a couple of other recent LMRbots to make a body for it out of a Dollar-store mixing bowl"

Welcome to the chamberpot robot club! haha

For a piece of terd, I like it :) Its scary, but kind of cute... I should just stop talking now

You want to see scary, just wait until I get the video up.  Mofo is noisy!

For extra bling you should make it shiny.  Polish your Terd!

It's funny you should say that-and I'm not kidding here-I was this close to hitting him with a coat of chrome spray paint and giving him a red cylon eye! Totally would have been Galactica turtle.
The iPad case caused the repeat. Not me...