Tunes are go!

Holy Roland, I can't believe it's taken me until 2013 to move my music hosting off MySpace! The only thing more embarrassing is that people have invested money in MySpace in the interim... good luck Justin.

Anyway, I've got three albums up: Singlestar (the latest) along with collections of tracks for both film music and older stuff. The site is here, but I've also embedded players below. Enjoy!

Krylenko (Bandcamp)

Singlestar


Composed - Music for Film


Collected 1999-2009

Remixing a mixer

Is there a recording musician who hasn't owned a Behringer mixer? They're cheap as chips and do what they say on the tin.

I'm surprised my current model is only the second I've owned in 15 years of mucking about with music gear. It's a tiny thing, but just about perfect for the space I have and inputs I need. That said, it didn't come with an aux send. Those are super-useful, especially with my new spring reverb, so I decided to add one.

A bit of parts diving, soldering, and gluing later and I've got a mono out, stereo return aux bus. Had to scrap the tape I/O but don't think I'll be missing it. Here's a pic of this truly classic Junkbox Raider mod:

I could have made it uglier, but I ran out of time.

 

I broke a what?!?!

I've busted a lot of stuff over the years - mostly the poorly constructed and therefore delicate projects I'd built, but also plenty of electronic components, hardware, circuit boards, etc. I've even broken and bent a few small tools.

But until yesterday I'd never snapped off half a pair of needlenose pliers so cleanly it looked like they'd been sawed apart. How's that even possible? (Sure, my finger strength is unparalleled, but I wield it gently. :)

I'd post a picture, but I can't be bothered to dig 'em out from under the pile of Robosapien discards clogging up the trash. Trust this random guy on the Internet, though - it really happened.

Maximum information, minimum post

I've been planning for a while to write up some research I worked on in 2011 involving intrinsic "motivation" for robots. We got a workshop paper out of it, and I presented the results to the ECE department last year. I also planned to extend it into my thesis project.

But... the lab went through some advisor round-robin and the project fell apart, and I just don't feel like writing it up into a full post anymore.

In a nutshell, our robot learned a policy for a partially observable Markov decision process (POMDP) to learn about objects in a space by manipulating them with its arm, then assigning object classification probabilities, with Shannon information gain across all objects as the learning reward.

Here's the AAAI workshop abstract, with a link to the full PDF:
http://www.aaai.org/ocs/index.php/WS/AAAIW11/paper/view/3960

Here's a fun picture of the robot!

Cricket, the toy robot that never was

I decided earlier this year to build a robot as a gift for a young relative. I've always found Braitenberg vehicles interesting and wanted to create a mobile robot with simple sensors and the ability to switch among several Braitenberg-type "personalities" (light-following, sound-avoiding, etc.).

Thus Cricket was born.

Cricket with, well, some things working.

Turns out I underestimated the chaos of the target environment, with multiple even younger siblings running around. Only a totally bombproof gift would work - which Cricket is not.

That, plus some irritating bugs I don't feel like ironing out, means Cricket is now abandonware. But not forgotten!

Testing the light pods.

Full details and more pics after the jump.

Hot glue FTW!

How did it take me so long to discover hot glue?!?!?! Everyone else smears it on their robots and projects, but somehow it never occurred to me to try it. As an inveterate epoxy user - what a revelation!

Sure, it can get messy. But the adhesive power, the (literal) flexibility, and the absolute trifle of time it takes to set up are mind-bottling.

I just built a set of contact bumpers for a small robot in about 10 minutes, including time to mount them on the robot itself. With epoxy I'd still be waiting for the bumpers to set up, then I'd have to mount them tomorrow and wait another day, and it'd still be fairly brittle.

Now I'm on the prowl for anything that needs gluing - just like way back in the day when I discovered duct tape. Thanks, hot glue gun! 

Neural networks part 2: Evolving a "living" robot

In my first post on neural networks, I discussed training the network using gradient descent - a pretty straightforward optimization method. This project took a completely different approach: evolving the network's weights with genetic algorithms. 

Our project team designed a virtual agent (robot) that learned to avoid obstacles while acting autonomously to "work" and "eat", maintaining its own internal conditions in proper balance like a living animal.

The virtual robot (green circle) navigates from the green "health" waypoint to the red "work" waypoint while avoiding the gray obstacles.

We started in simulation, planning to implement the working system on a physical robot, but ran out of time to get the hardware side functioning. C'est la vie robotique! We did make sure our virtual agent would use the same motor commands as the real robot, so the simulation wasn't completely disconnected from the real world.

Full details, including the multilevel control architecture we developed, after the jump.