Random Thought Of The Day

Posted on 2009-08-05 by M. Eric Carr

I wanna know:

Why does Windows’ Task Manager list the size of the “System Idle Process” as nonzero? Also, why is it different, on different computers? My desktop apparently takes 16K of memory to do absolutely nothing, while my laptop (memory hog that it apparently is) takes 28K to do just as much nothing-per-second.

Now, I know 16K or 28K is a drop in the bucket these days — my laptop has 2GB of memory and my desktop has 3GB* — but honestly, why should doing nothing be anything more than a line or two of assembly?

* Yeah, 3GB. Not only does the 32-bit version of WinXP not always play nicely with 4GB of memory, but Core i7 processors have three memory pipelines, rather than the more understandable two or four. (Maybe Intel decided they liked Google’s “Don’t be evil” and decided to go with “Don’t be normal” or something. I dunno.) At any rate, Core i7s like their memory in threes. Go figure.

Posted in Coding, Humor, System Administration | 1 Comment

A step in the right direction

Posted on 2009-07-23 by M. Eric Carr

Well, that would explain it…

The reason that the quadruped robot was doing the “funky chicken” instead of walking smoothly was mostly due to a major bug in the gait angle calculations. The angle of the leg is the sum of the “shoulder” and “knee” joint angles — but the angle commands to the knee servos weren’t taking the shoulder angles into account. This caused a really inefficient, jerking motion, rather than the relatively smooth gait that was intended.

Oops.

It’s fixed now (and has a new chassis and circuit board). The video shows it moving more-or-less in a straight line, but with a few modifications to the gait tables, it can turn, at least in shallow circles.

Next on the list:

  • Rubber tips for the feet

  • Improvements to the turning routines

  • Turn-in-place functionality

  • Reverse (basically, just run the gait tables in reverse order)

  • Wireless control

  • A second microcontroller to handle control and communications

Posted in Coding, Digital, PIC Microcontrollers, Robotics, SIGMA Walking Robot | 1 Comment

Walker robot progress

Posted on 2009-07-15 by M. Eric Carr

Well, it moves. The gait algorithm is still handcoded instead of evolved (I’m working on finding a physics sim I can use for that), and is less than efficient — but at least it’s going in the right direction. The plan is for it to eventually be a hexapod — maybe even with three degrees of freedom per leg — but for now, it’s a 2DOF quaduped. Once it’s walking reasonably smoothly and efficiently, the plan is to make it remotely controllable and embed a video camera — probably using XBeePro modules (from SparkFun, where else?).

The version in this video is still based on a cutaway plastic project box; it has since been moved to a proper chassis produced on the 3D printer. This doesn’t yet do much for the gait, though.

More about the robot as the design evolves…

Posted in Coding, Digital, PIC Microcontrollers, Robotics, SIGMA Walking Robot | Leave a comment

The end of an era

Posted on 2009-06-12 by M. Eric Carr

TV in the US goes digital today.

As someone who has seen firsthand the magic that the Digital Revolution has brought us, I know that this is a Good Thing(tm). As a card-carrying Paleotechnologist (not to mention child of the 70’s), though, I can’t help feeling a little nostalgic for good old analog TV.

TV was simpler then — in Northern Virginia, our TV choices were channels 4, 5, 7, 9, 20, and 26 (plus some UHF channels if we aimed the antenna just right and occasionally channel 3 from Richmond if we aimed the antenna right *and* the moon was in the seventh house yadda yadda.)

Not better, mind you — just simpler. Paleotechnologist or no, I still wouldn’t give up our age of TiVo, YouTube, Hulu, DVDs, and flat-panel screens — even if the 70s did have better music.

Loran is probably next. They already did away with Omega, and with the Galileo navigation system coming online, there will be an alternative to GPS.

At least we technological dinosaurs will have our memories — from watching Sesame Street on a 1975 Ford TV (which I still have and which still works!), to navigating from Norfolk to Milwaukee and back with a Compaq Plus suitcase computer and a Loran-C receiver (GPS was for rich folks back then.)

Posted in Digital, Nostalgia | 2 Comments