Author Archives: clem.law@usa.net

Surgical Mask for Smokers: 1919

1918MaskMasks during a pandemic are nothing new, as shown by this illustration during the Spanish flu epidemic.

Shown here is Edward T. Duncan, modeling his invention, an influenza mask suitable for smokers. To the standard issue mask, he affixed two corn plasters, one on the inside, and one on the outside. A hole is poked, and the cigar or cigarette can be inserted.

“When you draw on your cigarette, all the little germs hovering around take advantage of the chance and try to get in. But when they have gone through the fire of your cigarette they become purified, and are quite harmless by the time they get to your lungs.”

When not smoking, the hole was plugged with a cork.

This invention appeared in the May 1919 issue of Popular Science.



1945 Crystal Set

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Seventy-five years ago this month, the March 1945 issue of Radio Craft showed this crystal set idea, sent in to the magazine by John Haynes of Doe Run, Missouri. The coil, consisting of about 125 turns of wire, was mounted on a coil form slipped over an old shield can, and snugly affixed with gummed paper. A second can slid over the coil, and was adjusted to tune the set.

The magazine noted that a similar idea appeared in the January 1943 issue of the magazine.



1935 Light Beam Communicator

1935MarPM85 years ago this month, the March 1935 issue Popular Mechanics showed how to make this light communicator, said to have a range of about a half mile.

The receiver used a caesium photo cell, which the magazine said could be had for about $3. This was fed into a two-tube amplifier which could drive a speaker or headphone.

For audio amplification at the transmitter end, the system used the household radio receiver, and the magazine explained how to hook up the microphone. The the light beam generator used a system I’ve never seen before. Instead of electrically modulating the light bulb, a mechanical approach was used. The speaker was disconnected and the output was instead connected to a magnetic headphone that had been modified. The outer cap of the headphone was unscrewed and cut so that most of the metal diaphragm was visible. Then, the “diaphragm is slipped off and taken to any plating firm to be finished in the same manner as an audio headlight reflector.” The headphone was reassembled, and the result was a mirror that would vibrate in time with the sound. An auto headlamp was used to illuminate the mirror, and this was focused through a lens with a focal length of about 12 inches.

The result would have been a narrow beam of light that was modulated. At the receiving end, another lens was used to focus the beam on the photo cell.

For a unique science fair project, the advanced student could adapt this project using modern materials.  When I was a kid, I built a similar system using a flashlight as the transmitter.  The bulb was wired in series with the secondary of an audio transformer.  The primary was fed by the output of an amplifier.

For the receiver, I used a solar cell fed directly to the input of an audio amplifier.

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Testing a Battery with a VOM

1970MarEIFifty years ago, Electronics Illustrated showed this pointer for testing batteries with a multitester. Just measuring the voltage won’t do much good, as the battery will probably show its full voltage, even if depleted, with no load.

The solution is to put a resistor in parallel across the battery. If the battery shows full voltage across this 100 ohm resistor, it’s probably good.

These days, multitesters are even cheaper than they were 50 years ago.  In fact, occasionally stores will give them away free.  If you don’t have one around the house, get one, as you won’t know what you did without it.

Some of the meters below give you an idea of how inexpensive they are these days.

If you don’t have that 100 ohm resistor in your junque box, you can also get it on Amazon.

Some links on this page are affiliate links, meaning that this site gets a small commission if you make a purchase after clicking on the link.



Cub Foods Grocery Pickup Review

20200320_113344During the pandemic, my family is minimizing as much as possible direct contact with others. We’re staying home, going out only when necessary, and staying away from other people when we do go out. To purchase groceries and other items, we’re ordering online. Earlier this week, I reviewed our experiences with Walmart pickup.

Today, we picked up an order from a local supermarket chain, Cub Foods. We had to chose a pickup slot about five days out. We placed a small order initially, and kept adding to it during the week. For our Walmart order, we had to make any final changes about 12 hours before the pickup time. With Cub, we were able to make changes up until the last minute.

CubOrderWhen our order was being shopped, we received a text alerting us. We were able to log in to the app (or to the website, which I used) and chat directly with the person doing the shopping. When a product was out of stock, we were given a suggestion for a replacement product which we could either accept or decline. In a couple of cases, she texted us and asked for our choice.

A few items (rice, hand sanitizer, and toilet paper) were completely out of stock, and we were informed. We were informed when she was finished, and at the store, we alerted them that we were there using the app. The employee loaded the groceries into our car, with no personal contact needed. Unlike at Walmart, we didn’t need to sign in, and it was possible to stay back several feet.

CubPUOne big advantage of Cub was that the whole pickup took place without any close contact with the employee.  We opened the door, and he loaded the groceries.  At Walmart, there was the additional step of having to sign for the order on a small tablet computer, meaning that there was some chance of contamination.  Update:  As of March 25, Walmart is no longer requiring you to sign for the order.  At Cub, you identify your car on the app (including the license number), so there is no need to sign personally.  The employee simply comes out to the right car and delivers your groceries.

Walmart had two advantages over Cub. First of all, it was possible to get a slot slightly sooner. It appears that slots open up at midnight (local time, I’m guessing) and you can make reservations for the next day. It appears that with Cub, you need to make the reservation about five days out. Also, with Walmart, it appears that you can purchase any item in the store. So if you need items such as hardware, electronics, or even clothing, Walmart would be the best option. Since Cub is a grocery store, you’re limited to mostly groceries. (However, like any major supermarket, Cub always has a small selection of non-grocery items.) Also, Walmart has somewhat lower prices overall.

Despite those advantages of Walmart, we preferred Cub. Being able to communicate with the shopper with respect to substitutions was a very nice touch. If you think of an item at the last minute, you can add it in.

At Walmart, most of the substitutions were very reasonable, and we did have the opportunity to reject them. But there was no mechanism to ask for a different replacement. With Cub, that was possible.  At Walmart, you reject any substitutions when you’re picking up your order, with no opportunity to get a different replacement.

To chat with the shopper while your order is being filled, you of course have to be available online at the right time. When life gets back to normal, perhaps that will be difficult. For the time being, though, that’s not a problem.

Of course, unlike at Walmart, nobody crashed into our car when we were picking up items at Cub. But that’s hardly the store’s fault. We’ll probably use Walmart again if we’re in more of a hurry or need non-grocery items. Their service was very good. But for most of our grocery needs during this crisis, we’ll probably rely on Cub.

Some links on this page are affiliate links, meaning that this site gets a small commission if you make a purchase after clicking on the link.  The links to Cub, however, are not affiliate links, and we are not compensated if you use them..



1945 One-Tube Four-Stage Receiver & SW Converter

1945MarRadioCraft3Seventy-five years ago this month, the March 1945 issue of Radio Craft magazine carried this one-tube receiver, submitted to the magazine by Sgt. L.R. Blattner, who was stationed at Tinker Field, Oklahoma. According to the serviceman, the set gave the maximum performance for the number of components, and it’s hard to dispute that claim. Despite having only one tube, the set had a stage of RF amplification, AVC, and two stages of AF.

The signal is first applied to the pentode section of the dual tube, passed through the RF transformer, and then detected by the plate and cathode of the triode. Then, it’s applied again to the pentode, now acting as an AF amplifier. From there, the signal goes back to the triode where it’s amplified again.

The magazine also carried the shortwave converter below, sent in to the magazine by Richard E. Held of Sioux City, Iowa, who reported that he received stations from Tokyo to Brazzaville.  It tuned 7-11 MHz, and used two tubes that the writer had lying around.

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Treaty of Versailles Rejected: 1920

On this day one hundred years ago, March 19, 1920, the Treaty of Versailles was rejected by the U.S. Senate for the second and last time. There had been a prior straight vote on the treaty, which was rejected. A second vote included fourteen reservations proposed by Sen. Henry Cabot Lodge. The final vote fell seven votes short of the two-thirds majority needed to ratify.

The war formally ended for America in 1921 when Congress passed the Knox–Porter Resolution.



School Distance Learning: 1930s

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1937Oct15BCDue to the cornavirus pandemic, schools around the country and around the world are grappling with the issue of how to provide instruction to students by distance learning.  It isn’t a new phenomenon, however, as shown by this article from the October 15, 1937, issue of Broadcasting magazinei

During a Chicago polio epidemic, schools were closed, and the city’s radio stations banded together to broadcast classes for students at home.  The program was so successful that it was to continue even after school was back in session.  Broadcasts would not duplicate material from school, but would supplement it, with a cultural value directed at both adults and children.  The city’s stations would each donate 15 minutes per day of airtime to the programs.

Other schools facing quarantine were looking to Chicago’s successful venture as inspiration for their own.  The Chicago schools had been contacted by educators and broadcasters in the U.S. and Canada for pointers.

The photo above is another example from 1938.  This one isn’t because of an epidemic, but because of a fiscal emergency in Dayton, Ohio, as recounted in an earlier post.

 

 



Walmart Grocery Pickup Review

 

WMPUDuring the pandemic, my family wants to keep to an absolute minimum our direct interaction with others. If they’re infected, I don’t want to catch it. And just as important, if I’m infected, I don’t want to spread it to them. To minimize the amount of shopping we need to do, I’ve decided to alternate between online orders at local stores, and Amazon orders.  I think we have enough supplies for the duration, but it’s nice to maintain our normal diet, including things such as fresh milk and bread.

Today, I picked up our first  Walmart order, which was more or less a normal weekly grocery order, including milk bread, soft drinks, and canned goods. We happened to need some superglue, so we added it to the order, showing that you can order anything in the store.

I placed the original order online on Friday afternoon, and picked it up today (Monday). This was the earliest slot available, so the process does require some planning. As of today, no slots were available, and the website asked me to check later. So perhaps this is our one and only order. At the very least, the process does require some planning. However, once you reserve the slot and place the order, you are able to add and remove items from the order, up to about 12 hours before the pickup time.

Update:  The Walmart site seems to have changed since I posted this.  You can now make reservations only for “today” and “tomorrow.”  The best bet seems to be to check the site right after midnight.  For example, if you check at midnight Monday night/Tuesday morning, you’ll be able to reserve a slot for Wednesday.

Today, I received an e-mail telling me that my order was ready. The e-mail instructed me to check in on their app to let them know I was on the way, so I installed the app on my tablet. It turns out, however, that this is unnecessary. You can simply proceed to the store, park in the designated area, and then call from your car to the number posted there.

A couple of minutes after calling, the Walmart associate came out with our order and loaded it into the car.  It was a well organized process.  Our bags were in tubs labeled with my name.  I noticed that some were marked “cold,” and some “ambient.”  I apologized for not helping her load it, but I explained that I didn’t want to risk contaminating her.  I did have to sign on a small tablet computer.  Update:  As of March 25, you no longer need to sign for the order.  I was able to stand back 6+ feet the entire time.  I got out my hand sanitizer, and sanitized my hands immediately after doing so.

walmartsubstitutionsWhen placing the order, I was able to select whether I would be willing to accept a substitution for items. Some items were out of stock, and I received a substitute item. In most cases, the substitute was a slightly different brand, size, or flavor. For example, they were out of the two-pound package of white cheddar cheese, so I received two one-pound packages of sharp cheddar, for one cent less than my original order.

The only case where the substitute wasn’t useful was our order of a spray can of Lysol (which we were ordering for a neighbor). In the case, they gave us Febreeze, which really wasn’t useful. However, the choices were e-mailed to us, and we had the option of removing the item. I told the associate that if it was difficult, not to bother, but she quickly found the item, scanned it in, and we were credited for the amount.

We ordered a package of toilet paper and were hopeful that we would get it, but it was out of stock and no substitution was available.  We also ordered a container of Ensure for an elderly friend, but it was also unavailable.

Overall, the process worked very well.  If it remains available during the current national emergency, we’ll definitely make use of it again.

DentThe only glitch was, upon leaving, another customer backed into my car.  Despite what sounded like a loud crunching sound, it left only a small dent in the rear door.  I’m sure if I took it to a body shop and let them know the other driver’s insurance would pick up the tab, they would gladly replace the door for hundreds of dollars.  On the other hand, it’s a twelve year old car, and I doubt if I’ll pursue the matter.

In the car, I had a pencil and sheet of paper, so I tore it in half, wrote my information on one half, and then had the other driver do the same.  When she was finished, I had her keep the pencil.  She was apologetic, and in better times, I would have shaken hands before we left.  In the time of pandemic, we just went our ways.

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1945 MacGyver Power Supply

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According to Wikipedia, MacGyver was born in either 1951 or 1952, so he couldn’t have been responsible for this wartime power supply. Instead, it was sent in to the the March 1945 issue of Radio Craft by one Richard F. Reed of Jacksonville, Florida. But MacGyver must have been inspired by Reed, since this power supply ingeniously makes use of available parts, despite wartime shortages.

Reed needed to 90 volt power supply, and used this circuit to get it out of a 1.5 volt battery. The transformer could have been an audio output transformer, but Reed had on hand a model plane induction coil, so he used that. In lieu of an inverter, he used a 1.5 volt buzzer in series with the transformer.

For a rectifier, he used the starter from a fluorescent light. He reported that the supply put out 95 volts at 25 mA.