Great Beginnings for Vintage Computing in Seattle; VCF PNW

The pitch to my wife was simple: “Feel like spending the weekend in Seattle?” That’s how I ended up at the inaugural Vintage Computer Festival Pacific Northwest last weekend, and I’m glad we made the five-hour drive into The Big City to check it out. Hackaday is a VCF sponsor, after all, so it seemed like a great excuse to make the trip. That it ended up being two consecutive days of great Seattle weather was only icing on the cake of being able to spend time with fellow retro computer aficionados and their dearest bits of old hardware, in a great museum dedicated to keeping computer history alive and accessible.

The fact that Seattle, home of Microsoft, Amazon, and dozens of other tech companies, has until now been left out of the loop in favor of VCF East in New Jersey and VCF West in Mountain View seems strange, but judging by the reception, VCF PNW is here to stay and poised to grow. There were 20 exhibitors for this go around, showing off everything from reanimated PDP-11 and Altair 8800 control panels to TRS-80s from Model 1 through to the CoCo. Almost every class of reasonably transportable retro hardware was represented, as well as some that pushed the portability envelope, like a working PDP-8 and a huge Symbolics 3640 LISP workstation.

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Large area x-ray detector

This is an x-ray detector built by [Ben Krasnow]. It’s an interesting combination of parts working with an oscilloscope. The result is an audible clicking much the same as you would hear from a Geiger counter

He’s measuring backscatter, which is the reflection of x-rays on other objects. Because the signal will be quite weak compared to waves emitted directly from an x-ray source he needed a large collector to measure them. He started by gutting an x-ray image intensifying cassette. This has a phosphor layer that glows when excited by x-rays. The idea is that the glowing phosphors do a better job of exposing film than direct x-rays can. But [Ben’s] not using film. He built that pyramid-shaped collector with the phosphor material as the base. At the apex of the pyramid he mounted a photomultiplier tube (repurposed from his scanning electron microscope) which can detect the excited points on its surface. His oscilloscope monitors the PMT, then issues a voltage spike on the calibration connector which is being fed to an audio amplifier. Don’t miss his presentation embedded after the break.

[Ben] mentions that this build is in preparation for a future project. We’d love to hear what you think he’s working on. Leave your guess in the comments section.

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12kW solar collector

Though not much info is readly available about it on the web, [Joe Carruth] is trying to build publicity (and venture capital) for his home-built solar electric generator. At its essence, it is a Stirling dish system with an adjustable composite mirror surface. This means that instead of having to rotate the entire contraption in order to follow the Sun, [Joe] only has to make  the mirror segments pivot. A Stirling steam engine at the tip converts the energy into the movement used to generate electricity. Solar power plants (or ‘farms’) that are emerging are beginning to consider the advantages of using more efficient Stirling dishes rather than less efficient solar panels. If anyone has an idea as to how [Joe] can automate sun tracking for the mirrors, please post it in the comments. A couple more videos on the topic (in general) are available below: Continue reading “12kW solar collector”