Amateur astronomers learn to love the dark.
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.
Continue reading iOS 7 Brightness Problem…
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…
A Raspberry Pi computer set up with an A/D daughterboard
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!
Continue reading 2013 Big Island MATE ROV Competition…
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.
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!
Continue reading STEMpede at Parker…
Eventually it will break.
This is the rule for household appliances. I would just prefer that it not be a two year old microwave that I had installed into the kitchen cabinetry. Yes, I can probably fix it… after I dismount it and lower it out of place. A task much easier typed than done. No matter, I am on-call this weekend. I will be around the house all day anyway, may as well get something productive done.
An over-the-stove microwave costs a few hundred dollars, too much to just run out and buy a new one. Not enough to justify a repair call. I do not even want to think of what it would cost to get a repairman out to the house. Driving from Kona? Hawaiian rates? I can think of few easier ways to get robbed.
Microwaves are pretty easy to work on, just get the cover off and everything is right there
I can fix this. Microwaves are relatively easy. Plus, it is an LG, you can actually buy the parts without going through an authorized extortionist. I have long ago learned not to buy certain brands
, restricting appliance purchases to companies for whom you can actually find the manuals and buy the parts.
Continue reading Appliance Repair…
Another exhibit built for public outreach functions. It was completed and used for the recent W. M. Keck Observatory open house. You will also be able to see it at the upcoming AstroDay fun in Hilo.
Ray-tracing is a standard way to analyze optical designs. The technique allows the optical designer to follow the path of each ray of light through a system of lenses and mirrors. While ray tracing used to be done with pencil and paper, it is now done on a computer screen. What I had never seen was this process done in the physical. But I can figure out how…
A laser ray trace table used to demonstrate the focal point of a simple lens
Take a few laser line modules, a bit of sheet metal and paint, a bit of circuitry and we can do this!
In the photo you can see the idea… Five red laser line modules are aligned across a table. Stick a lens section in the beams and you can observe refraction as it happens. Using a double convex lens, all of the beams converge to a focus. A clear demonstration of the basic principles of optics!
Continue reading Laser Ray-Trace…
A DS1013S delay line IC photographed for an eBay sale
My big project over the last month has been cleaning out the garage. Not the easy part either, but going through the pile of electronics parts I have on hand and organizing. Part of that organization is culling out and reducing the pile, a task that must be done every few years. I have repeatedly filled the trash can beside my workbench. Scrapping or simply throwing out some of the accumulated parts and bits. Some stuff is just obsolete, some is well past any sort of reasonable shelf life, some I just do not need anymore.
There is some stuff that could have some value. Components and gear that could be sold, for that stuff there is eBay. I have eight listings active right now, and a few more I need to set up. Much of the stuff is electronic components, ICs and DC-DC converters. I am making some money from this stuff, not a lot, a few hundred dollars so far, perhaps enough to buy a few new toys.
In an age of cost cutting on products to compete in a very competitive market place, some producers seem to go too far. Reducing the quality of the product to the very edge in order to shave a few pennies. One consequence of this has been more battery leaks, with Duracell being by far the worst offender. Seriously, why does anyone still buy Duracell products! This time it was a friend who brought me the latest corrosive disaster, a Wii Balance Board with a mess in the battery compartment.
The battery compartment of a Wii Balance Board after the repair
At least the balance board was easy to get apart, just a mess of screws on the back to remove, a few minutes with a phillips screwdriver. First remove the feet with three screws each, then the backplate with another ten screws. The unit is essentially a fancy bathroom scale with load cells in each foot. Rather nicely made, the engineers did a good job here.
Opening the case reveals the good news and the bad news. Good… The battery compartment is removable with just another couple screws. Bad… The damage here is severe, the small circuit board under the battery compartment is heavily corroded, traces and components destroyed. Good… The complex circuits for the unit, the processor and transmitter, are on another circuit board on the other side of the balance board and are untouched. Bad… The battery contact plating is gone, these are unusable. Even the wiring harness is damaged.
Continue reading Repairing a Wii Balance Board…