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A Treasure Trove of Electronic Projects and History...

9/24/2015

At one time there were a fairly large number of magazines that featured amateur and hobby electronic projects. This began long before the internet and its deadly impact on print publications. But in the long history of DIY electronics, Popular Electronics was a really big deal.
There was an interesting convergence of events that led to the extreme popularity of home electronic projects. First, there was the invention of the transistor in 1947 at Bell Laboratories. Second, Heathkit began selling kits to the general public so that they could build everything from oscilloscopes to robots! Heath actually began in 1912 selling aircraft parts but recognized the post-war economic growth and came to the table with a very successful business model. But it was apparent that there was a market for wide scale dissemination of electronic projects and technology was moving quickly. And, Popular Electronics began to fill that need.
Of course there were magazines that covered electricity and particularly, radio. After the widespread introduction of radio broadcasting, the field of radio transmission expanded to include amateur radio and related interests. The early 20th century was a great time for beginning experimentation. But, it was a time that had somewhat of a limited focus, and in time, that would change.
In 1954, Ziff-Davis Publishing introduced the world to Popular Electronics, a monthly magazine with electronic projects, access to parts, (by mail of course), and ideas to stimulate the budding hacker. It was the “World’s Largest Selling Electronics Magazine” with a circulation in 400,000 by 1963. A competitor, Rival Electronics World, merged with Popular Electronics in 1972. The magazine underwent some changes in name and then ceased publication in 1985. But, it was bought by Gernsback Publications and came back in 1989. But, once again the magazine stopped publication in 1999. And like the Phoenix Rising, it ended with the name Electronics Now, and its final issue was in 2003.
But, the story actually has a good ending as there is now a complete archive of all of the issues over the entire time span of the publication’s life. All issues are available in PDF's complete with advertisements. But, be careful when ordering as many of the companies are out of business! The link is here. Time to warm up the soldering iron!

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Embossing Powder Made at Home...

5/9/2015

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Update 4 August 2015: There is now a composite image showing the extracted polymer ( in these examples the polymer came from a floor finish from Holloway, sold at Walmart) with pigment inks, and color experiments with the colorless Versamark ink after the second video. This photo and effort is provided by Kristina Roberts, who has shared her work with our community. Thanks, Kris! Please check the comments for Kris's work with this alternative polymer.
Two videos below: Video 1 shows the results and video 2 illustrates the process.

Thermography is frequently considered to be raised printing typically used for business cards, wedding invitations, and other decorative printed material. The process provides a third dimension of height. The procedure is essentially the use of a slow drying ink, a thermoplastic polymer, and a source of heat. The wet ink receives the powdered resin and is heated until the polymer flows and adds the dimensional effect and becomes solid again. Raised print is also useful in the production of Braille in place of punched indents. Although a fairly mature industry with its beginnings in the early 20th century with copal or varnish resins, there are new uses being discovered. For example, the rubber stamp process has been adopted by crafters and has become a billion dollar business. It has become an “at home” art form with cards, scrapbooks, and new areas of artistic expression. The companies in this business now sell several kinds of ink, embossing, (thermoplastic) powders in many colors, and other peripherals to make the hobby easier and more versatile.
I became interested in the polymers used in the thermographic process but found very little in the literature and patents. There is an abundance of information on the equipment used but most of the embossing powders are proprietary and even the MSDS literature was of little help. I was fairly sure that someone had made some of these embossing resins at home but a search turned up no process. Additionally, after reading several crafting blogs it seems as though there was a desire to find such a method that was easy to do at home and used readily available materials. After many failures and frustrations I have been able to extract a clear embossing powder from a common floor finish. Since this in an open source website I welcome comments and community additions and suggestions to improve and refine the process. Here is the recipe and the two products required for the extraction of clear embossing powder:

Pledge Floor Care Finish, 798 ml (27 fluid ounces). This was called “Future” until 2008. It is manufactured and sold by S C Johnson. Follow any cautions listed.
Distilled White Vinegar.
Procedure: Add 2 parts of cool water to one part floor finish in a disposable container and not one used for food. With stirring, add vinegar slowly until the polymer becomes thick and very easy to see. Stop adding vinegar at this point. Pour polymer into a sieve or funnel/coffee filter and drain. Return the drained polymer into the original container and add water as a rinse. Drain and transfer to paper towels, spread material and allow to air dry. Reduce particle size by placing dry polymer into a sandwich bag or Cling wrap and apply pressure to make a powder. If a finer powder is required, pass the particles through a dryer sheet as shown in the video.
How it works: The acrylic floor finish is a stable emulsion and is stable due to the fact that the emulsion is kept at a pH of greater than 9. Remember that a pH of 7 is neutral. When we add vinegar that has between 3 and 9% acetic acid, the pH of the emulsion goes down and the polymer precipitates out. The variability of the acetic acid content is the reason that there is no fixed ratio stipulated.
There are other alternatives to consider but they all have limitations. Laser toner is useful but there is no colorless toner and the colors are very limited. Powder coating for metals is an option but very expensive and not generally available in small amounts. So, this project is an alternative material to the commercial products and it is a lot of fun to make your own!

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Dextrins and Alcohol...

3/26/2015

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This is a companion post to the one on Palcohol (powdered alcohol) on the Trendcasting page. It deals with the science of powered alcohol and how the product is most likely manufactured. I use the word likely as the product is proprietary and the formula is considered secret. But, we all know that proprietary never stops anyone from trying to figure out how it is made. In August of 2014, Paul Adams authored his method of making alcohol into a powder product in Popular Science, here. Other attempts have been made with varying degrees of success. But all of the ideas that I have seen use dextrin in one form or another as the starting point. And, that makes sense as dextrin is considered a safe material and can absorb liquids to some extent. The first patent to use dextrins to absorb alcohol for mixed drinks was issued to General Foods in 1974. (On Google Patents search 3,795,747).
Dextrin is a type of low molecular weight carbohydrate produced by modifying starches. The starches can be selected from corn, potato, or even tapioca. These starches are treated by various enzymes or acid hydrolysis and form a starch-type sugar. They are all water soluble but have some very distinct characteristics. In the Popular Science article, the author used a relatively easy to obtain maltodextrin. But, he also suggests that a cyclodextrin might be a better choice. And, he is absolutely correct with that assumption. We can think of maltodextrin as a one dimensional powder that has some fur-like extremities that absorbs fluids and is used in the food industry to soak up oils. It is a short chain starch sugar and is used as a food additive as well. It can be sweet like a sugar or have no taste at all. Cyclodextrin is a totally different and is also called a cycloamylose, made of molecules bound together in a ring. But, cyclodextrins have a neat little trick that makes them ideal for making alcohol into a powder.

You really don’t have to know anything about chemistry to understand why they work so well. So, if you want to, disregard the OH (hydroxyl) and O2 (oxygen) symbols just look at the shape of the material. It is a toroid and allows some materials to be trapped inside! The interior is favorable to somewhat hydrophobic (water incompatibility) materials like alcohol. But, the exterior is hydrophilic (water compatible) and dissolves easily in water. Of course this is a simplified description and does not allow for arguments about alcohol and its polarity. But hey, we are after all making powered booze.
Cyclodextrins are becoming more readily available so there will be more homemade alcohol powders in the future. Whether or not the packaged alcohol even makes sense will be determined by consumers.

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Coffee with White Clumps and a Bioplastic...

2/7/2015

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If you add milk to coffee or tea you may have noticed small white clumps floating around the surface and wondered what they were. And although they are not desirable, they may offer no more than a harmless appearance. On the other hand, it may indicate milk that has become spoiled. But, there is a fair amount of chemistry involved in the formation of these little clumps. So, let’s look at what happens in your nice hot cup of coffee.

Milk is a blend of several naturally occurring ingredients including fat, protein, and sugar. Milk is a colloidal suspension which simply means that the fat and protein molecules are very small and are floating around freely and not attached to each other. The light is refracted in this colloid and that is why it appears white. We can consider the protein molecules (casein) to be a monomer that can potentially be attracted to each other to become a polymer. There will be more on the polymer later in the post.

So, in milk the casein molecules are floating around individually and naturally repel each other. But, if the milk becomes more acidic (lower pH) the casein molecules attract each other and begin to clump or curdle. They separate from the liquid portion now called whey. And, as in most chemical reactions, increased temperature accelerates the clumping. But that fails to explain how the milk becomes more acidic. All milk whether pasteurized or not contains bacteria. It is harmless and just swims around doing something that can change the milk over time. Hence, the “sell by” or “use by” date on the container. The bacterium slowly eats the natural sugar in milk called lactose. One of the byproducts of the bacterial feast breaks lactose down into lactic acid and the pH drops. And, as the pH drops the clumps increase, and the milk will spoil. Actually, it is the smell of lactic acid that indicates spoiled milk. So, if the clumps are only sporadic in number and the milk smells normal, it is fine to use the milk. But, it is an indicator that the milk is on the way over the hill! But, the good news is this is exactly how some cheese is made. The milk is heated and an acid is added like vinegar or lemon juice and the curd is separated from the whey. But, what about the above mentioned casein polymer?

Well, as the lactic acid forms the curds, the individual casein monomers unfold and reassemble in a connected chain forming a polymer or plastic. When the curd is kneaded and the water removed, the mass can be molded and shaped and will become hard. But, it is very biodegradable and will break apart with water. However, chemists in the early 1900’s discovered that they could make a more permanent and functional product by washing the curds in a 5 % solution of formaldehyde to cross link the polymer. These products (referred to as the Galalith process) were sold as buttons, fountain pens, and other decorative items for over 70 years. So, with milk we can make butter, cheese, yogurt, and pour it in our coffee and cereal!

If you want to make your own bioplastic from milk and vinegar, just search “casein plastic”, or “milk plastic”. There are multiple sites to show you how. Got Milk?

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AAAA Batteries from 9 Volt Battery...

12/17/2014

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Video Below:

We are all familiar with the range of alkaline batteries in all of their sizes, voltages, and capacities. The most common of these portable storage devices are the D, C, AA, and AAA. But, there are less well known types used as well. Type N is fairly common but not as popular. Another one that is widely used but less frequently available is the AAAA (LR61) or usually called the quadruple A. These smaller than AAA cells, are used in computer styli, laser pointers, LED flashlights, and headphone amplifiers. I use them when I need a smaller physical battery than the AAA but with reasonable milliamp/hour capacity. But, I have never bought one! They are not generally available in local stores, so some time ago I found that the Duracell 9 Volt batteries had six quadruple A batteries inside. So, the resulting video shows how to extricate these little gems easily and save some money as well. I have not tried other alkaline 9 volt batteries but some may be identical. If you have found other sources of batteries with these cells please comment.

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Ballistic Gel for Pellet Guns...

11/21/2014

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I recently had the opportunity to have contact with a reader who had hosted a guest post, (Growing Mushrooms at Home), snoman8. But, it was about an experiment that I posted almost a year ago on Reusable Molding Material. (Here) He wanted to try this experiment with a pellet gun as the ballistic gel. My suggestion was to use the initial formula but to reduce the glycerin by about 50 % to more closely resemble human tissue (Photo above courtesy of snoman8). To my surprise the formula worked very well and comes close to the standard from the INS National Firearms Unit. The most commonly used formula is a 10 % ballistic gelatin which is prepared by dissolving 1 part of 250 bloom gelatin into 9 parts of warm water by mass. It is then chilled to 4 C (39F) for use.
Ballistic gel has been used for many years as a substitute for human muscle tissue and the effects of projectiles causing wounds. The material used is based on gelatin and the formulation is standardized against swine muscle tissue which is close to that of humans. Here is the formula used by snoman8 and the relevant data:
14 grams gelatin, 70 ml water, and 35 ml glycerin. The mixing process is identical to the video in my post listed above and really should be replicated for the best results. The completed material was molded in a plastic container 3 inches by 2 inches (76 mm X 58 mm). The pellet used is a .177 caliber lead shot from a distance of 10 meters (32 Feet). The muzzle velocity was approximately 400 ft/s. The pellet traveled 2.75 inches (69 mm) through the 3 inch direction.
My sense is that the use of glycerin as a plasticizer is perhaps a better choice than with gelatin alone and the completed gel is reusable by heating and recovering the pellets. As always, comments and questions are welcomed and a special thanks to snoman8 for his effort in expanding information…

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A Toy to Demonstrate Biomimicry...

10/2/2014

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Video Below:

Biomimetics or biomimicry is the imitation of the models, systems, and elements of nature for the purpose of solving complex problems. More simply, it is the adaptation of the natural movement and habits of plants and animals to solve human problems. A good example of this adaptation is the loops and hooks of the popular material Velcro. It mimics the action of burrs and the way they stick to each other. Almost everywhere we look in the natural world we can see models worth copying. From the way snakes use serpentine movement and muscle contraction, jellyfish propel themselves, and the action of light on plants to provide growth, we are surrounded by fascinating motion and function.
One of the earliest attempts at replication was the flight of birds. I can imagine that the very earliest humans on the planet must have wanted to fly. Over 400 years ago, Leonardo da Vinci designed many types of flying machines using birds for his inspiration. One of the most popular was the ornithopter, which is the basis for the toy in the attached video. In the 1980’s a French patent was filed by Brevet with the design for this toy bird that also has US patent coverage. You can see the patent at Google patents under 5,163,861. (Best to copy and paste). I have been fascinated by biomimicry for a long time and thought that this toy was a good example of the process. Enjoy the video and the close up photo of the mechanism.

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Under The Dome With Wasps...

9/5/2014

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Video Below:
I have found over the years that watching insects and by following the movements of various species, that a great deal of interesting behaviors can be observed. For this post I have been following wasps, (from the order Hymenoptera) to see if I can alter the activities of the colony. Wasps, in many parts of North America are called yellow jackets, and are very different from bees, particularly the honey bees. While bees are typically docile and collect nectar that in turn pollinates plants, wasps are parasitic and live on insects. They do inadvertently pollinate plants to some degree as they also seek nectar as a supplemental food source when they become adults. They like corn as there is a great deal of available sugar. And, they are extremely aggressive and will swarm to sting any intruders or threat to the colony. I accidentally found this hive in an abandoned hole left by a gopher or other digger. It happened to be right next to my corn in a raised bed. When I went to pick some corn they attacked and I slowly retreated. I was surprised as wasps typically build hives in protected areas and not in holes in the ground. But, I began to wonder if an altered entry would prevent them from normal colony activity. So, I modified a cylindrical transparent container and called it a dome as in the TV show, which I refuse to comment on! From the video you will see as I did that this colony was quite large and very aggressive. At one point there were at least 20 wasps around me or on me but I did not run or show fear so they did not sting me. Hey anything for science! Enjoy the experiment…

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What Projects Would You like to see on this page?

8/4/2014

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Over the past four years I have posted a variety of projects and information that I thought may be useful to my readers/viewers. Some have been very well received as was the “Anodizing Aluminum without Battery Acid” and it has been translated into at least 15 languages around the world. The post on “Reusable Molding Material” also received many comments and community response. Also, the “Static Electricity Detector” was read frequently. But others either have generated none or very few comments. So, I am not sure if my efforts are wasted, no comments necessary, or useful in any way. So, I am reaching out to you for some feedback and direction.
Despite the fact that I maintain four separate topic pages, the Science and Technology page is my main interest. I have been pursuing what I hope will be interesting, entertaining, and informative posts. But it would be helpful to know if you want chemistry, physics, electronics, or other types of projects. So, I would appreciate the time it takes to write a short comment to guide me in my choices of science topics.
Some of my projects take time to research, develop, and test. I try to offer some originality and versatility and I frequently have failures. (Don’t we all?) I could copy other sites but there is little value if the project requires no thought process. I usually have some pretty bazaar ideas and they may fall outside of what you may want. For example I am working on an infrasound project, (sounds below human hearing), and a silk screen photo emulsion made at home. But maybe you want something else and I could use the feedback to craft new science fun. I am also open to guest posts if you have a project that you would like to share. Leave a comment and I will post my email so we can chat! Thanks, Ken…

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Etch A Sketch with Push Buttons: An H-Bridge Demonstration...

7/7/2014

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Video Below:

Although this post has a plotter working like an Etch A Sketch™ it is more about changing motor direction with a mechanical H- bridge. It is a simple way to demonstrate how the “real” integrated circuit works.
Small DC motors can be found in many toys, computers, printers, and RC systems, and the surplus market has every conceivable type of motor with varying voltage, torque, and RPM. One of the well known aspects of a DC motor is that it is easy to reverse the direction by simply reversing the plus and minus connections from the battery or DC source. But, literally changing the polarity manually seems a bit difficult to do quickly. So, an integrated circuit called an H-bridge is used to complete the task electronically. But, like many integrated circuit chips, it is not obvious how the task is accomplished. So, I decided to make a mechanical H-bridge with just momentary switches to illustrate how the chip works. And, rather than just spinning motors, I thought that making an Etch A Sketch™ looking device might be more interesting.
It is important to say that neither the mechanical dual H-bridge nor the X-Y plotter was ever meant to be finished projects. The H-bridge is for demonstration only, and the plotter is a test bed for project ideas that I can try and make. I have used DC motors, steppers, and servos to experiment with microcontrollers and the plotter was assembled with very little thought to any serious application. After all, it is built on foam board! Not a serious choice for a plotter! But, some of my projects are built for fun and entertainment as well as information. The link for ITP Physical Computing is here. I did make a mistake when describing the switches reversing the X direction. I should have said switches B and C. Apologies! So enjoy and comment.