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The Journal of David A. Johnson, P.E., page 8 |
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Last Updated
on:
Monday, April 21, 2008 04:37 AM |
| Summer 2006 |
| The revenue from the Discover Circuits website continues to drop. The traffic
to the site is only a little down from last year but the overall income from the site is about half of what it was this time last year In
the course of looking for new links, I have discovered that there are several new sites that have actually stolen material from DC. This
hurts our ability to generate income because these sites drive away traffic from DC. “Build a better mousetrap and someone will steal it.”
That is what has happen. I want to thank all our visitors that continue to come back. We have been under a contractual agreement in
which Penton Media was to sell banner & skyscraper ad for the site. Do you recall seeing any? No, I’m not surprised. Over the course
of 91 weeks only about 15 weekly ads ran. Come November, I certainly hope that, when we approach advertisers directly that we will be more
successful. Based on the questions in the
DC Forum, I started a new section called “Hobby Circuits.” I want this section to be directed to those who have a workbench at home and are
interested in tinkering with electronics. The section will include projects for the do-it-yourselfer and for students. I think I might
move some of the DC forum material and some from the Circuit Solutions section stuff into a new Hobby Corner section. Perhaps that section
will attract more attention.
The DC forum is struggling to find its audience. Even though I try to answer most of the questions brought
up and I post some original circuits and concepts that I find interesting, the forum still only produces less than 2% of the total traffic to the
DC site. This business journal section does not even show up on the radar, which means it is less than 0.1% of the total traffic.
The wife has been busy adding more material to my other Discover Solar Energy site. Traffic to that site is slowly growing but still only amounts to
about 400 viewed pages per day. I’d sure like to see it break the 1000 pages per day mark before the end of the year.
We had to remove the forum from the Discover Solar Energy website. The forum became a target to many
spammers. It was a real war. We would remove the inappropriate posting and ban the person from posting again. However, they
would just come back under a different name. When the bad postings reached over 20 a day, we were forced to pull the plug.
I posted my resume on the Monster.com website and on several temporary job agencies. So far, I have not
received any interested parties. Perhaps I’m too old to be hired by anyone. I can’t afford to retire, so I have to find another source
of income. Maybe I can learn to drive a truck or some heavy equipment. I think I could get some satisfaction out of digging a big hole
in the ground with a big machine. |
| Pull-String Generator: I’ve been helping an inventor develop a more efficient way to
generate electricity from human power. He took my basic idea of an automatic retractable pull-string mechanism (similar to the mechanism
used to start a lawn mower) and has been working out some of the mechanical details. If he is successful, he might have a nice generator,
which could crank out 40+ watts of power. I might come up with some different battery charging circuits for him. Some of the newest AA
NiMH rechargeable batteries can be charged in 15 minutes. That works out to about 50 watts of power for a pack of 4 cells. My cell
phone battery is a 3 volt lithium ion battery with a 1 amp-hour rating. Four AA NiMH cells with a 2.5 amp-hour rating would equal about 4
cell phone batteries. Perhaps I could design second battery charger, taking energy from the 4 AA cells and dump the power into a cell phone
battery. |
| ebay Sales: I’m trying to earn some extra money by selling off some of my old test
equipment and some big electronic components I will never use. After several years of buying and selling audio books, my wife is an expert
at posting stuff on eBay. The money we make from the eBay sales might be enough to make a car payment or so. My wife is looking for
something else she could sell on eBay on a regular basis. If anyone out there has some ideas, let me know. |
| HP RPN Calculator: An associate of mine has been working on reverse engineering HP’s
line of reverse Polish notion (RPN) type calculators. He thinks he may be getting close to being able to offer an equivalent calculator for
sale. HP quit making these devices years ago and no other company has developed any good RPN units. RPN calculators are much more
efficient for scientific calculations than traditional devices. When my friend gets done, I’ll post a link to his calculators on this site. |
| Neighborhood Garage Sale: Once each year, my home owner’s association sponsors a
neighborhood garage sale. They don’t allow individual sales any other time of the year. The wife and I decided to lay out some old
computer stuff and some heavy furniture and see if someone would take them off our hands. We sold a few computer related items, gave some of
the stuff away and what we don’t sell took to the Goodwill store. At least there is less clutter in the house. |
| Long Range Laser Sensors for US-Mexico Border: A few years ago I designed a nice
battery powered foot traffic monitoring system for the American Border Patrol. The battery powered circuit used a pair of geophones to
detect human motion up to 100 feet away. Once detected, the sensors used a powerful radio transmitter to alert the patrol of activity in
that area. The packaging of those systems was well designed, so they were nearly invisible. Only a short camouflaged antenna pokes
above ground. The only way the installers can locate them, to change the battery once a year, is with a GPS receiver system and the known
coordinates of the buried systems. Scores of the systems were installed and are still in operation. The systems were successful in
helping to apprehend hundreds of illegal aliens entering the US. When I was working on the geophone system, I also proposed a long range
laser system, which could monitor up to 20 miles of fence line along the border. It now appears that the US will in fact be using such
technology along the border. I only wish I could have had been able to work on it. It would have been a fun project. |
| Light Weight Alternators for Wind Generators: Many years ago I worked with a clever inventor
by the name of Gene Fisher (www.fisherelectric.com), who developed a highly efficient brushless motor, which also worked extremely well as an
alternator. His 10 pound device could crank out 10,000 watts. I think this light weight device would be perfect for many wind
generators, where total weight on top of a tower needs to be limited. I think I might see if Gene’s company would be interested in
developing some alternators for the wind energy industry. I’d like to see thousands of 10KW machines installed. I have learned that
Gene Fisher passed away a few years ago. Sorry to hear that, he was quite an inventor. |
| Wind Power Display: If you are doing a wind survey for a piece of land where a wind
generator might be installed, you would like to record not the wind speed but the wind power. There is a reason for this is. It turns
out that power from the wind tracks a “cube” function. Every time the wind speed doubles, the power from the wind increases by a factor of
8. Often, a few days of a high wind condition will generate more average power than a full month of a light breeze.
Measuring the wind speed is pretty simple. Wind speed and direction indicators are fairly cheap. Some
wind speed anemometers produce a string of pulses whose frequency increase with speed while others produce a DC voltage proportional to the wind
speed. To record the wind power, this information has to be fed through a cube function circuit. A microprocessor would be a good
choice for this kind of number crunching conversion. The raw voltage or frequency data would be fed to the microprocessor, which would then
compute the cube and produce an appropriate DC output voltage to be displayed by some panel meter or it could feed the information to a computer.
But, suppose you were an old analog guy like me. How do you make a cube function? I know of two different ways to do it. I’ll
work out some of the details and post it on the DC forum. |
| PV Cell Tester: Suppose you are making your own photovoltaic solar panel. You have a
box of solar cells which are supposed to be identical. However, some may produce slightly less electrical power than others. How can
you quickly match up a set of solar cells? All you need is a nice bright halogen lamp, perhaps a 12v type DC power supply (12v battery), a
pulse width modulation (PWM) control circuit, a quality PIN photo diode and a digital current meter. The idea is to point the light from the
halogen lamp, so it produces a uniform spot of light onto a flat surface. Then, by positioning the photo diode within the cone of light and
connecting it to the PWM circuit, you could insure a consistent illumination level every time. To measure the quality of the solar cells
under test, they would be connected to a digital current meter while illuminated with the fixed light level. The short circuit current of
each cell can be used to match cells. Those cells that don’t make the grade are not used. |
| Ice and Snow Sensor Circuit: I picked up a small consulting job the other day. I’ll be
designing a simple circuit used to detect the accumulation of snow or ice on a sensing device. The device is used by railroad companies to
control powerful heaters surrounding the large switches used to switch metal rail lines. Those switches have to work in all weather and the
sensor will be a key component. It is a small job but every little bit helps. |
| High power 125KHz RFID exciter: Another small job I got involved with was the design
and construction of a high power 125KHz RFID tag exciter. The challenge was the dealing with the high voltages produced by a 50 watt
transmitter. Those voltages easily exceed 2000 volts AC. |
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