Electronics – Page 6 – A Darker View

A Matter of Control

As the new year is well underway I find myself in the midst of my major project for this year. For the next few months I will be replacing the control system for the Keck 2 dome. The project is well underway, but the real work remains ahead of me.

Keck 2 Dome PLC — The Allen-Bradley PLC/2 that controls the Keck 2 dome and shutters

It is a project that is long overdue. The current controller for the dome and shutters is an Allen Bradley PLC/2, a thirty year old piece of equipment that is sadly obsolete. Yes, a PLC, programmable logic controller, one of those machines I thought were a completely horrible way to do anything. I was appalled when I first encountered this technology, now I have to master it.

Parts for the PLC/2 are still available, but the programming software is a real issue. The software runs on a DOS (as in pre-windows) operating system, and does not run under the emulation modes of later Microsoft systems. You need a real DOS computer, something that is a bit rare these days. If the controller running the Keck 2 dome were to fail, I am not certain we could repair it.

I have the computer that is used to do the programming in my office, an ancient Compaq Portable III. Portable is an odd word to use with this computer, it weighs over 20lbs and is huge by modern laptop standards. This museum piece still works! Last month I booted it up and wandered through the file system. At power up I was greeted by a monochrome amber screen and a DOS prompt. I still remember a few basic DOS commands, enough to check things out. It appears that all of the software and files are still present on the hard drive. Sometime I need to see if I can indeed program the old PLC/2. If something goes wrong in the update I need to be able to revert to the original control system.

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Video Games Then and Now

For the first time in decades I have been playing a video game.

Growing up, we had a state of the art video game console in the house, an Atari 2600. This machine was impressive… For the late 1970’s. Specifications included color graphics, 160×192 pixel resolution, and monaural sound. My brother and I played for hours, eventually beating some of the joysticks to the point where they required replacement. I mastered Space Invaders, I could play through all of the levels, wrapping back to level 1 for as long as my stamina allowed.

Atari Tanks — Atari tanks game, circa 1978

One of the games bundled with the Atari was Combat, there were four games on the cartridge including a tank game. I look back on that first game, one of the first we played on that console, with a bit of nostalgia. Two tanks maneuvered around a simple obstacle course, with a point awarded for each shot that hit the opponent. The audio was similarly quite simple, a basic growling sound meant to sound like engines and a few sound effects for the shots.

In the intervening decades I have seldom played video games with any great intensity. There was an Apple II space adventure game called Elite that I did play for a while in the 1980’s, but little else.

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Radio Shack Files for Bankruptcy

Like most electronic hobbyists, I have an odd relationship with Radio Shack. In our youth it was the one local place you could buy basic components… Resistors, connectors, wire and other parts could be found there, without waiting a week for an order from a mail order catalog. The selection was always pretty sparse, the quality was hit or miss, and the prices were too high. But, if you needed something quickly it was the place.

Radio Shack Waimea — The Radio Shack location in Waimea in the KTA center

I even worked in a store for a summer in high school, learning what it was like on the other side of the counter. An experience that left me wondering why anyone would want to work in retail sales.

Then for many years, through the 90’s and the early part of the 00’s Radio Shack neglected the hobbyist business, concentrating on cell phones and accessories. Recently they have returned to their roots, restoring the kits and components section of the store. This time with Arduinos and other more modern technology. It was a move that many in the electronics community greeted with some enthusiasm.

Still, in recent visits looking for a last minute component I have found the selection just too minimal to be truly useful.

Word that Radio Shack is filing for bankruptcy and closing 1,750 stores is no surprise. According to news report the corporation claims $1.2 billion in assets and $1.4 billion in liabilities.

Apparently our local store in Waimea is not slated for closure in this first round. The future of any particular store is far from certain. Sprint has agreed to purchase many of the closed stores, but details are far from complete. Certainly many of the stores occupy desirable locations and are ripe for acquisition.

What emerges from bankruptcy will be interesting to see. But my guess is that the Radio Shack that has long been a fixture in our lives is gone.

The 2014 MATE ROV Big island Regional

This is the seventh year I have travelled to Hilo to help out. The seventh year of watching students attempt a difficult mission of the bottom of a swimming pool. The 2014 MATE ROV Regional competition was held Saturday, May 11th at the Hilo High School pool.

Ready for the Water? — The team from Kailua High School ready and test their ROV for a mission in the 2014 MATE Regional in Hilo

The mission this year is to explore a Great lakes shipwreck. As usual the “shipwreck” is made of PVC pipe, shade cloth and other hardware store parts. By measuring the wreck and discovering various features the identity of the ship could be determined. The robots are also built with hardware store parts, most with frames of PVC pipe. Interestingly there was a notable presence of parts manufactured with laser cutters and 3D printing this year. It is great to see these technologies making their way into educational programs, giving students unprecedented power to design and create.

Some teams did quite well. I was impressed by the professionalism and dedication it took to build and operate the ROV’s. Teams travelled from neighbor islands to compete in Hilo, raising the funds for plane tickets and to ship the ROV’s they had created. Besides the underwater activities the teams must also make presentations and supply technical reports that are also scored.

Scout — A scout class ROV getting ready for the water

It takes a lot of work to properly judge the competition. I have noted that the rules and scoresheets just keep getting longer every year. I must tip my hat to the folks that make this competition happen every year, giving the kids a chance for invaluable experience.

Who won? Not really that important, even failure in the pool results in learning, even if the lessons are uncomfortable. The students will take that experience forward in life.

iOS 7 Brightness Problem

Amateur astronomers learn to love the dark.

Astrophoto Acquisition — A small netbook computer busy running an astrophoto setup

Unlike the rest of the human species we enjoy seeing the night sky and have learned not to fear the darkness, rather to embrace it. This phlisophy is carried over to our devices as well. We set our computer screens for minimum brightness with red on black color schemes. We understand dark adaptation and what it means for our vision.

You may note that Darker View uses a dark color scheme. This is not by chance, there was a great deal of thought put into the light on dark color scheme here on DV, with full understanding of the advantages of dark on light schemes.

Many people do not like light on dark schemes, avoiding websites that use such colors. Other folks far prefer such color schemes, particularly people who spend long hours at the computer, programmers and CAD technicians in particular. Programming environments and CAD software make switching color schemes easy, understanding the personal color preferences are critical to good software useability.

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Raspberry Pi, Python and SPI

It has only taken me much of the day to get it working. Hours spent reading documentation, searching for postings on the same issue, ripping up the code and trying completely different approaches. Hours of frustration mixed with some solid learning.

Victory was seen in three bytes.

Three bytes shown on the logic analyzer display and in the Python console window. The same three bytes… The hardware and software agreed. The serial timing also looked great, chip select going low when it was supposed to, a 500kHz clock, all of the edges just as the data sheet specified.

Victory is connecting an eight channel A/D converter IC to a Raspberry Pi computer with the hardware SPI module. Four channels for voltages, four channels for temperatures. The project is coming along nicely. Will talk about what in a later posting. Meantime my thanks to Connor Wolf, Louis Thiery, and Brian Hensley. It was their method and SPI code that worked!

A small victory, another step forward, this is what hackers and makers do…

Raspberry Pi Data Acquisition — A Raspberry Pi computer set up with an A/D daughterboard

Postcard from the Summit – Test Leads

2013 Big Island MATE ROV Competition

For the sixth year running I made the drive to Hilo to help in judging the Big Island Regional 2013 MATE Underwater ROV competition. Too much fun to miss!

As usual Keck provided much of the official staff. This is the fault of Keck software engineer Al Honey, the head official, who drafts the rest of us into being there! An engineer from Liquid Robotics and a couple folks from the observatories in Hilo rounded out the judging staff. Add teams from schools all over the island and mix with water to create an event.

A ROV built from PVC pipe and bilge pumps maneuvers the course at the 2013 MATE ROV regional competition in Hilo

The missions continue to increase in complexity. This year the task was a simulated undersea research platform. Various instruments were in need of upgrade or servicing. Opening a hatch on the “undersea instrument platform”, disconnecting power, removing an instrument, installing a new instrument, removing bio-fouling, a long list of tasks, each worth a few points in the final tally. Never-mind the instruments were made of PVC and the bio-fouling was actually pipe cleaners, it still was not easy!

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STEMpede at Parker

Take two old scanners, two VCR’s, a stereo amplifier and tape deck. Place on a table with an ample supply of screwdrivers, wire cutters and other tools. Mix in a dozen middle school kids and observe the results!

As you might expect a little chaos appears. Chaos is good… Embrace the chaos! Use the result to have a little fun while learning.

Electronic Sacrifices — A few electronic sacrifices await the arrival of the students.

The event is STEMpede, a day filled with science, technology, engineering and math at the Parker School here in Waimea. With Keck Observatory essentially right next door, it makes sense that our engineers and astronomers can put on quite a day for the kids.We were joined by one of the engineers from Liquid Robotics and a couple local physicians and paramedics for a variety of activities and talks.

I was not going to simply talk, I have always believed learning is best done by hand. Some of the gear was from my own garage, some off the electronics disposal pallet at work. A lineup of old electronics greeted the kids, then I opened the tool-bag!

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Category: Electronics