Power to electric motors from a digital controller is never easy

Hooking up 2 electric drive motors seems like a simple task on the surface, but never is in practice.  Here’s my mockup of a circuit I’m going to use.  The meat of the control circuit is an L293D Quadruple Half-H Driver. Now that the breadboard prototype is working, it’s time to assemble the thing permanently on a printed circuit board.  Leave a comment if you want the schematic for this, it works pretty well with no noticeable gitter thanks to a bunch of capacitors.

It’s time to make the robots

I’m building a small robot this week.  We’re calling him Evadotbot (Caleb came up with that).

He’s pretty simple, a two motor gearbox will control 2 wheels, the 3rd being a caster wheel so he can spin in a circle.  He’s controlled by a simple motor controller chip and powered by 4 AA rechargeable batteries.

His “brain” is an Ardunino Duemilanove which has a whopping 32k of memory.  If you’re not a computer geek, think about that Commodore 64 you could get in 1981 and divide it’s RAM in half. Or, go to the  It’s shown here in it’s “skull”, aka an Altoids mint box.

To top it off, he has an infrared range sensor for “eyes” and an Xbee radio so he can send data back to me and eventually communicate with his peers.

More pictures to follow as he gets assembled.

On reading the important stuff, like say the Constitution

The Oaths of Enlistment and the Oath of Commission in the Armed Forces of the United States both include the line:

I will support and defend the Constitution of the United States against all enemies, foreign and domestic; that I will bear true faith and allegiance to the same;

That’s a powerful statement. I’ve repeated those words on enlistment myself. You’ll support it, you’ll defend it.  Maybe even at the cost of your own life.

Whether or not you’ve sworn to that line or not:

Have you read the Constitution of the United States?  The whole thing?

Seems like something we should be reading don’t you think?

Always be the worst musician in the band

I just finished Chad Fowler’s book “The Passionate Programmer“.  There are a lot of great concepts in this book and I recommend reading it even if you’re not a programmer.
There is a concept in this book that he talks about that really stuck with me: Always be the worst player in the band.

Chad has been a jazz saxophonist for years. His concept is a simple truth about your level of talent relative to the people in the room.  The idea is that if you’re the least talented, you can’t help but play towards the level of the more talented.  Conversely, the more talented people play more like the less talented people. You can’t help in a group setting but to become more like the other people you play with.

I’m an engineer type professionally.  I work in computers and electronics and have extensive experience over a broad range of topics on both related fields.  I’m VERY good at what I do.  Lately, I find that I’m often the best engineer on the projects I’m working on.  According to Chad’s concept, the people around me are getting better, but I’m standing still, or worse, maybe even going backwards.

This is a gross oversight on my part.

As a musician, I’ve NEVER been anything but the least talented in the group. The people I play with a generally VERY good. I’m by no means good these days, but my playing over the last few years has improved dramatically because of it.

Today, I’m going to find something to get involved with where I’m the least talented in the room.  Hopefully I won’t break something 🙂

Where do I find THAT level of conversation?

There is a movie that you’ve probably not heard of that I can watch over and over again without tiring of it.
The Man from Earth, a mostly overlooked independent film from 2007 made on a shoestring budget rivets me to the screen. It takes place entirely inside a tiny house and in it’s yard.

The premise of the story is that the protagonist, John, is a Cro-Magnon cave man, now some 14,000 years old.  He never ages, gets seriously sick, or dies.  The story weaves in an out of a single afternoon where he reveals this fact to a group of friends as he prepares to leave town before people start to notice he doesn’t age. He’s clearly been close to this group of friends and this afternoon is the first time in his long life where he’s found a group of people he trusts enough to try telling them his crazy truth.

The part of the story that is truly captivating to me isn’t so much the ideas explored as it is the manner at which his friends engage in the conversation about it with him.  Some of them are very open to the ideas, and some find some of his ideas sacrilegious.

What’s remarkable is that they all stay for the conversation.  They probe him, they listen.

Having this kind of conversation is what really blows my hair back.  It’s one of my reasons for doing Evadot.

What blows your hair back?

I’m not good enough is not good enough

I’m hearing this stuff WAY too much lately:

  • I’m not smart enough for that
  • I’m not ready for that yet
  • I want to but this is outside of my area of my expertise
  • I want to, but I can’t because of my job
  • When I get this degree/certification then I’ll be ready for that dream (this one is my biggest pet peeve)

These phrases are tiring to me.

If they start coming out of your mouth, just stop.

  • You’re good enough. Really.
  • You’re more than smart enough (turn off the damn TV you’ll be 50% smarter in 10 mins)
  • Your job isn’t working, find another one.  Not some day. Today.
  • Your degree isn’t your ticket to success

The time to do that thing is now.

Get off of your ass and go do it.

Why is Evernote asking to be paid bad?

One of my most used programs is Evernote.  I use it all day, every day.  From my Mac, my Ubuntu boxes, my Blackberry and my iPod touch.  I’m a premium user which costs me $45/year.  A reasonable price to me.
Last night, they updated the Mac client to include a small ad box in the lower left hand corner that serves some ads (and a bunch of really awesome features).  It’s a small box and as a premium user I have a preferences option to disable it (which I did).  There has been a minor uproar this morning about privacy issues and some people using the words “Evernote is adware”.

As of right now I have no reason to believe that they are mining my notes information to serve me ads (a privacy issue which would be a serious problem considering what they do as a service).

It’s standard practice for web services to have a free add supported version and an ad-free paid for version.

I’m not sure I see what the fuss is all about.

They provide a great service and want to make some money.  What’s wrong with that?