Posts Tagged ‘ failure ’

Tricopter: Now in Five Broken Pieces

Curse my impatience.

I got wired control pretty much working, so I went ahead and hooked up my XBees (wireless link) for testing. I had my hand on the chassis just in case, but I guess I didn’t apply enough pressure—it went full throttle on its own (I had barely touched the joystick) and flew off the counter. In two seconds, the tail rotor ripped through my sweatpants and scraped my calf, hit the chair, broke free of its axle and ricocheted into a corner (I spent a good 10 minutes trying to find the detached rotor piece). Somehow, I got three cuts on my left hand, and the acceleration was such that it snapped the chassis into four pieces. Granted, the chassis was made of scrap PCBs, but it was double-layered! All three propellers are shattered and useless.

Anyway, my mother freaked out.

The good news is that I think my motor shafts are okay. My electronics also survived the accident.

I’m probably very lucky that I still have the skin on my fingers and got away with only a few cuts and a welt on my calf. Before I started this chassis build, I cut my thumb pretty badly when I lost my grip on a motor that suddenly accelerated to full speed and landed in my hand (it stopped when it spun itself free of the battery). The jagged edges of the broken rotors would have done much more damage. Why do I never learn from mistakes?

TODO: clean up mess, order new propellers, rebuild chassis, test, test, and TEST CODE.


MacBook Battery Swelling?

Last Tuesday, I took apart my 2nd-gen BlackBook to fix my squishy right palmrest (top was not flush against bottom case) when I was surprised by the heat and size of my battery. I don’t have a picture, but it looks like the one in this MacRumors thread.

The battery is thickest at the center. The heat melted the adhesive, so the rubbery back panel is separating from the metal part of the battery. The charge status button needs to be depressed further for the green LEDs to light up.

Summer’s coming on, and it’s pretty humid here in Kobe, so it might just have been the heat, but I feel that this has malfunctioned too easily. There was a battery update/replacement program, but that’s been discontinued since May 31 this year (zut!). Running GNU/Linux, I never got that battery firmware upgrade, and it won’t install from Mac OS installed on an external drive.

On the bright side, the battery still (just) fits, and the capacity doesn’t feel diminished. But I’ll get a new one next month, though, and keep this one as a backup.

And that squishy palmrest: apparently, the top case had been bent when I took it apart last year. I simply bent it back, and no more squish. :)