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

Issue 18,  August 2011- Page 1                                                                                                      Previous Issues     

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

Soap Dispenser Monitor

Wily was taking out the trash to the dumpster behind his house when his cordless phone rang.  It was from a medical company who had a problem.  The company manufactured a wide variety of products.  One of the products was an antibacterial soap dispenser which was used in hospitals.  The company wanted a method to indicate when a 2 liter bottle of soap was empty.  They tried several methods to detect when the bottle was empty but none of the methods proved robust enough.  Wily was intrigued.  He asked for more information...

con't page 7

Wily Widget,
the Lone Inventor
 with Gadget & Gizmo

WHAT THE WORLD NEEDS NOW is a....AC to DC Power Supply with 40KV Isolation

This request came from a company who needed an unusual power supply.  They required a low power DC supply assigned to a high voltage power supply, which was elevated above earth ground by 20KV.  The power supply needed to be connected to the 20KV supply.  They said that their circuit performed some logic function and communicated to a computer through an optical fiber interface.  The logic circuit could operate using a voltage from 2 to 3 volts and only needed a couple milliamps of average DC current.  The kicker with this system was that to insure no arcing, they wanted the supply to be able to withstand 40KV with respect to earth ground.  Wow!...

story con't on page 6
Human Walk Energy Harvesting Generator
By: David Johnson

There have been many different experimental methods used to try and harvest some energy from the body motion of a walking human. Some techniques use piezoelectric wafers, some use bouncing magnets inside coils and some use some other complex mechanism. 

I would love to see some experiments performed using the system illustrated below.  I believe that this method will prove to be much more efficient at extracting some energy from the human walk....

   story con't on page 4

Gapped Ferrite Pot Core Inductor     

I got a frantic call from a company who builds powerful ultrasonic cleaning machines.  Their machines use banks of 50 watt piezoelectric 40KHz transducers.  Up to 6 can be driven by a single driver board.  For years they were doing fine.  Then, for some reason the last batch of boards they were getting from their assembly house were not working right.  The units might work for a while but would then suddenly stop.  In each case one or more of the MOSFET power transistors which made up the driver circuit would be shorted and the unit’s fuse would be open.  They could not figure out why these units were failing.

 story con't on page 3

Bad Floor Sweeper

I while back I bought an electric broom type floor sweeper.  We needed something simple and light weight to pick up dog hair, crumbs and dust from the hard wood floors and the various throw rugs.  The “Swivel Sweeper” seemed like it would be perfect for this light duty application.  After giving the 7.2v battery pack a full over night charge, I turned the thing on and put it to work.  It seemed to do OK in picking up small bits and dog hair and it was easy to use.....

story con't on page 5    

Portable Solar Power System for Fence Installers

I while back, I was watching a crew of two people install a fence along a street near my house.  The main power tools they were using were a Skill type circular saw and a couple cordless drills.  They had a large flat bed truck with a small gasoline generator chugging along to supply the 120vac needed for the saw and to charge the batteries for their cordless drills.  They started their day early in the morning and worked until the late afternoon.  I figured they put in a solid 8 hours of work each day.....

story con't on page 2 

August 2011

Page 1 Back
Good Idea
gone Badly
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.