Archive for October, 2010

Visiting San Diego

Thursday, October 14th, 2010

I’ve been in Anaheim, California for a conference this week, and I had the happy opportunity over the weekend to drive down to San Diego and meet in real life a couple of long-time blog friends, Scott and Ben.

Keith's Restaurant sign

I knew I was in the right place as soon as I looked out my hotel window.

Scott Smith's laser cutter frame

Scott is building a copy of bdring’s DIY laser cutter, which looks fantastic. Over the weekend Scott was assembling the sleds that transport the mirror over the workpiece. It’s a very nice design — everything is modular and everything is adjustable.

Fly-milled delrin and aluminum

Scott and his machining mentor Peter generously demonstrated milling techniques on Scott’s Sherline mill. Shown is a fly cutter that was just used to smooth the surface of delrin and aluminum blocks. Although it’s not mirror-shiny, I was impressed at how easy it is (with the right cutting and feed rates) to clean up a face. Peter also demonstrated the use of an edge-finder to precisely position a hole drilled into the edge of an acrylic plate for the laser cutter.

Scott Smith's CNC mill interface

Scott’s mill came CNC-ready with mounts for stepper motors on all of the axes. Scott designed and built his own interface between the PC’s parallel port and the stepper controls, adding indicator lights and the all-important stop button.

Lemons on tree

California is full of things I’ve never seen before, like lemons on trees

Ben Wynne soldering an EasyBright

and people other than me

Scott Smith soldering an EasyBright

soldering together EasyBrights. I don’t have the microscope, though, so I don’t have to make the squinty face.

Ben Wynne's RepRap Mendel

Scott and Ben have both been interested in my progress (and lack of usable results) on my MakerBot CupCake and Ben had just finished assembling a RepRap Mendel when I arrived. It’s much more interesting in person than any picture or video I’ve seen has captured. Compared to the CupCake, it’s incredibly smooth, quiet, precise, and easy to calibrate. On day two, Ben was already churning out prints I envied.

Between Scott’s mill, Ben’s RepRap, and Scott’s laser cutter, they’re set to prototype just about anything. I did suggest that Scott should build a water-jet cutter next, but he wasn’t having any of that. I may need some time to warm him up to the idea.

Project boxes at Fry's Electronics

We paid a visit to Fry’s Electronics, a legendary California electronics components and computer retailer. Although they’ve transformed into primarily a big-box electronics store, I was still impressed with their hobbyist / components section, including a larger variety of project boxes than I’d seen in one place and a good selection of components, including SMT passives, right there on the rack for the buying.

Min Smith playing guqin

Back at Scott’s house, his wife Min was practicing her guqin, a Chinese instrument you may remember from a Jet Li movie. Having been raised listening almost exclusively to western music (“We have both kinds!” — no, not that western music), I found its tuning even more unfamiliar than that of the guitar — it’s not tuned in regular intervals.

Sunset over the Pacific

To top it all off, we had time to wander down to the beach for a California sunset. Thanks, Scott, for an excellent visit with good electronics, great food, and local sights!

Fixing Jeremy’s Ford Mach 460 Bass Amplifier

Saturday, October 2nd, 2010

Sometimes you get lucky.

Ford Mach 460 bass amplifier

My friend Jeremy has a 1995 Mustang that had the factory premium sound system in it when he bought the car used. The CD player was broken and he had the head unit replaced within a couple of weeks of owning the car. He later added a subwoofer.

I’ve always thought the stereo lacked clarity in the bass, and the head unit and EQ have had some quirks. Recently Jeremy pulled the head unit and found all sorts of interesting techniques used by the aftermarket installer that will be the subject of a later monologue … but one of the things we discovered is that the amplifier for the door woofers wasn’t working at all. Swapping it with the amp for the rear deck woofers caused them to go silent and the (shot) door woofers to work again (after resoldering their cut cables).

Turned out to be a delightfully easy fix.