Klein Bot

Kleins, robots, electricity


Try saying 'Klein Bot Blog' three times quickly

view:  full / summary

Octowobble Returns

Posted by Klein on July 6, 2011 at 9:21 PM Comments comments (0)

We're back! Octowobble is getting ready for the 2011 Atlanta Robot Rally. Stay tuned on this channel for further updates.

Techno Vest

Posted by Klein on February 13, 2011 at 12:46 AM Comments comments (3)

I am going to a Techno contra dance in a week or so, and I've been working on something suitably techno for that event.The concept is a music driven flashing vest. I had hopes of synching the flashing display with the music beat, but that's proven hard to implement on the Arduino, so I've scaled back a bit.

There's not much to show for the code exploration and breadboarding, but I've put up some pics of layout options in the Lilypad Vest album.

BTW, if you're interested in following the technical bits on beat detection, I started a thread on AVRFreaks.

Laser communicator

Posted by Klein on February 1, 2011 at 11:48 PM Comments comments (0)

Ben's research topic for the January "mini-term" was Transistors. As a demonstration we built a single transistor amplifier. Input for the amplifier was a modulated laser pointer beam driving an LDR voltage divider. Again, more pics in the photo gallery.

Jan 2011 Robotz Meeting

Posted by Klein on February 1, 2011 at 10:57 PM Comments comments (0)

Hey, it's been a long while, Christmas is past and good progress has been made on the home remodeling, so I'm back to posting a bit here and there. Tonight I'm sharing a few pics from the most recent local hobby robot club meeting and a new Arduino class hosted by Joe ( http://www.smileymicros.com ). Go check out the photo gallery.

Second Place at the Robot Rally!

Posted by Klein on October 24, 2010 at 9:33 PM Comments comments (0)

Octowobble was a great success at the 2010 Robot Rally. We placed second overall in the Polyathlon and first in the sub-contest Dead Reckoning -- much better than expected. I'm still collecting photos, notes, and thoughts from the last few days, and I'll post a more complete summary later. In the meantime, it's back to "real life" and getting full nights of sleep.

Update 10/26

Scores and photos are posted at the AHRC site.


Update 2/1/2011

Neglected to add this last Fall. Videos are available on YouTube.

http://www.youtube.com/watch?v=Q5pJFALx4co (at 3:00 and 6:45)

http://www.youtube.com/watch?v=Gv3TlvYtMKI (at 0:45 and 3:40)

Countdown: 38 hours

Posted by Klein on October 21, 2010 at 9:16 PM Comments comments (0)

The Rally competition begins at 11 AM on Saturday. I think I'm close to covering 5 of 6 events in the polyathlon -- line following and beacon finding are 4 of the 6, dead reckoning will be a shot in the dark -- just some trial and error, not real reckoning.

Now on to work on the beacon detector and to write some programs tonight.

Countdown: 57 hours

Posted by Klein on October 20, 2010 at 8:52 PM Comments comments (0)

Octowobble was nowhere near ready for his coming out at the local robot club last night, so he's being schooled on the workbench tonight. It may be a late one -- he's been very bad.

I did get some good tips on things to try.The best route was to switch from "simple anti-phase PWM" to sign and direction control.

With anti-phase PWM, you peg the PWM ("speed") pin high, and alternate the direction pin quickly. If it's forward half the time and back the other, the net power to the motor is zero. As the PWM balance shifts, so does the average power and the motor turns. The theory is that the ~500 Hz PWM from the Arduino is insufficient to properly drive the input pin.

I've switched a driver to sign and direction. This is an easy change, just un-tied the PWM from V+ and brought it out to an Arduino pin. I'm tweaking the software and testing is about to begin.


Did you know that if you comment out code, it doesn't run? For instance, if the code that actually writes to the motor driver pins is commented out and replaced with Serial.print commands, then the motors never actually turn, and there might actually be nothing wrong with the driver.

Further Update:

It works! I'm now switching to work on the beacon detector. I can't rely on their beacon since I've never had a chance to test against it, so I'm cobbling together one of my own.

Countdown: 104 hours

Posted by Klein on October 18, 2010 at 11:42 PM Comments comments (0)

I'm trying to squeeze in some functionality before the local robot meeting tomorrow night.

Current status: I've discovered that the twin motor driver board doesn't drive one motor well when both motors are connected. Short? E-m interference? Time for some more troubleshooting.


I thought this might be a quick fix, so I played the "just a little more, I've almost got it" game. I checked the datasheet "typical application" notes and updated some component values and tied an output pin high. But somewhere in the changes, I broke one of the drivers. Now it's 2 AM, and there's no sleeping in tomorrow. Maybe I can find a quick fix before the robot meet?

Off to bed.

Countdown: 156 hours

Posted by Klein on October 16, 2010 at 10:12 PM Comments comments (1)

Getting nervous ...

Just 7 days, wait, 6 and a half days until the competition, and I can sleep in tomorrow. Time for an all nighter, I think.

Turn on New Age/Techno soundtrack ... check

Warm up soldering iron ... check

Arduino programming cable ... check

Recharge batteries ... check

Here we go ...

10:30 PM

A flaky battery holder, so I tried a smaller 8 batt holder. But the motor driver won't work (as wired) on 8 batts / 10.6 volts.

11:24 PM

Ben's in bed, so I'm finishing the second driver on my own.

2:00 AM

Munchies attack! Time for coffee and cookies (frozen Thin Mints. Yes, I still have some. No, you can't have them.)

Driver assembled (with switch and LED power indicator)

Battery pack is fixed (fingers crossed)

4:30 AM

The cookies are gone, the coffee's long gone cold. But I'm still here.

I've drilled some holes and switched from solder to hot glue.

I'm still aiming for a working line sensor and motor drivers this weekend.

6:30 AM

Hooking it up. Mostly making connecting wires and routing them now.

(Getting tired, though.)

7:30 AM

All hooked up, untested as a whole system. Octowobble has line sensors and motor control. We're ready to follow lines, as soon as I get a program together.

Time for bed!

More progress

Posted by Klein on October 14, 2010 at 11:51 PM Comments comments (1)

We made a little progress over the last several days, but not as much as I had hoped. Ben and I both have been overloaded with our respective work/school assignments.

I've started a to-do list to help organize the remaining work.

motor driver testing

motor driver 2 build and test

rebuild the power bus (12 volt) with a fuse and all upward pointing pins

edge sensors

proximity sensing

beacon sensing

motor encoders

Anyway, there's a bunch of new photos posted in the Octowobble album. Enjoy.