HOME Schematics Hobby Corner Dave's Circuits Electronic Resources Book Corner Contact Info

Issue 4, December 2009                                                                      Previous Issues

See the Beagle Christmas Countdown

Let's drop in on Wily and look over his shoulder at his latest project....

Fireplace Fizzle

On a cold bright morning Wily was out shoveling show after a recent winter storm.  He had just finished throwing the last shovel full onto the side of his driveway when his neighbor stopped by.  After a few words about the nasty weather, the neighbor asks Wily if he knew anything about fireplaces.  Being the only technical person in the neighborhood, Wily often got unusual questions about this and that. Wily asked the neighbor if he was having problems with his fireplace.  The neighbor said that he indeed had a problem.  His gas fireplace would not turn always turn on.  Some days it did and some days it didnít. ....
con't page 7
WHAT THE WORLD NEEDS NOW is . Wind Power Monitoring Blimp
Wind energy is becoming more and more popular.  It is one of the fastest growing sectors of all the renewable energy schemes.  However, not every location is suitable for capturing wind energy. 

Trees, buildings and the lay of the land can often conspire to reduce the wind energy to useless levels.  One way to determine if a location is suitable is to monitor the speed of the wind over a period of time.  The conventional way is to erect a tall tower and position one or more wind speed indicators along it.  Data from those is then fed to a computer for later analysis.  But, erecting a tower can be expensive and time consuming....

  story con't on page 6

Bad Chinese Capacitors
By: Dave Johnson  

Iím seeing a disturbing trend.  For several years now I have seen many expensive electronic products die an early death due to poorly constructed electrolytic capacitors.  Nearly all of these bad devices are made in China.  Just last year I lost an expensive 1 year old HP printer due to a bad capacitor.  I traced the failure down to one bad capacitor, which failed shorted.  That shorted part killed a number of other parts.  So many parts were killed that repairing the printer was not practical.  A printer should last a lot longer than 1 year.....

  story con't on page 8

New Products 2009
New product announcements are made nearly every day.  I subscribe to many trade journals and each is filled with hundreds of flashy advertisements.  But, only a few of those product ads catch my eye.  Since Iím a circuit designer, I especially like those components that trigger many new application ideas in my mind.  Sometimes it is the smallest products that are the most useful.  I often discovered new products in surplus electronic catalogs.  The surplus companies often buy up stock that came from companies that went out of business.  Bad marketing or bad management may have killed a perfectly good product idea.  Their loss can be your gain if you can spot the bargain.                               
Magnetic Vehicle Motion Sensor
By: Dave Johnson
Many months ago one of my engineering associates (actually my software guy) showed me a neat vehicle motion detection system he designed.  To demonstrate how well the thing worked, he gave me a powerful bar magnet and told me to go out into the hallway, outside his laboratory office.  He told me to hold the magnet still while he turned on the system.  He then closed the door.  When everything was set, he told me to wave the magnet up and down.  I waited a few seconds, and then moved the magnet rapidly up and down, from my knees to over my head.  The alarm sounded.  I stopped moving the thing and the alarm turned off. ....

   story con't on page 4

Flaky Garage Door Opener              
On a hot summer day, I had just finished mowing my front lawn when my neighbor walked over to me and asked ďyouíre an engineer arenít you?Ē  I said that I was.  He proceeded to ask me if I might do him a big favor and have a look at his garage door opener.  I gave him a puzzled look but since he was just across the street, I wiped my sweaty forehead and followed him toward his house.  As we were walking to his place, he told me that for the last several days he was not able to close his garage door until later in the day, once it had opened. ....

 story con't on page 3

Bad Office Chair Wheels

Last year I bought a chair for my office.  It is classic style with a high back and five caster type wheels.  The chair sits on a large plastic pad so the wheels easily roll.  One by one every one of the original casters has broken.  I bought a set of five replacement wheels and over the course of about 3 months I had to replace every one of the original casters with the replacement wheels....

story con't on page 5    

Aluminum Pop Can Energy Source

Is it possible to convert the aluminum in a pop can into pure heat energy with high efficiency?  How much heat could a bag of crushed cans produce?.  

story con't on page 2 

December 2009     Issue 4

Page 1 Back
Good Idea
gone Badly
New Products Rants &
What the World
needs Now
Wily Widget

Imagineering Ezine    Discover Solar Energy Dave Johnson & Associates Faraday Touch Switches

 About Us   |  Advertise on DiscoverCircuits.com   |   Report Broken Links  |    Link to DiscoverCircuits.com  |   
Privacy Policy

Discovercircuits.com endeavors to credit original designers.   Please alert us by eMail so we can
delete links to material that have been copied without your permission
.   Thank you.

© Copyright of all original material on this website is the property
of David A. Johnson, P.E. (Dave Johnson & Associates ) unless otherwise noted.  

Linking is ALLOWED but COPYING any content or graphics to your web site is EXPRESSLY PROHIBITED.
All material is provided "as is" without guarantees or warranty of any kind, either expressed or implied.