Manual LCD Makes Information Display Tedious, Educational

The HD44780 is one of the first chips we learned about as a kid, and chances are good you’ve used one in your project at some point, and almost certain that you’ve interacted with one in your life. The character LCD is ubiquitous, easy to interface, and very robust. They come in sizes from 8 x 1 to 20 x 4 and even larger, but they almost all have the same pinout, and there are libraries in many embedded environments for interacting with them. [The 8-Bit Guy] decided to interface with one using just switches and a button, (YouTube, embedded) with the intent of illustrating exactly how to use them, and how easy they are.

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Life on Contract: Hacking your Taxes

You’re a contractor and people are paying you to work in your pajamas. It’s a life of luxury, but when tax time comes, you are in a world of hurt and you wonder why you even do it. Taxes are tricky, but there are some tools you can use to make it less painful on your pocketbook. With planning and diligence, you can significantly increase the amount of money that stays in your bank account. Continue reading “Life on Contract: Hacking your Taxes”

Giant Solderless LEGO NES Controller Gives Everyone Tiny Hands

If you were thinking “I should spend $130 on LEGO bricks and build a giant USB NES controller just to see what that would be like,” but you were afraid of spending that much money, [BrownDogGadgets] has you covered. He built a giant NES controller out of LEGO. The controller is designed in LEGO Digital Designer, which lets you create a virtual model, then get a full list of parts which can be ordered online.

The electronics are based on a Teensy LC programmed to appear as a USB keyboard, and the buttons are standard push buttons. The insides are wired together with nylon conductive tape. LEGO was an appropriate choice because the Teensy and switches are built on top of LEGO compatible PCBs, so components are just snapped in place. The system is called Crazy Circuits and is a pretty neat way to turn electronics into a universal and reusable system.

If that controller is too big, they’ve also used the same circuit with some laser cut parts for your own controller. If you do want to go even bigger, take a look at [Baron von Brunk’s] LEGO NES controller, which used the electronics from a real controller.

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Low Background Steel — So Hot Right Now

The nuclear age changed steel, and for decades we had to pay the price for it. The first tests of the atomic bomb were a milestone in many ways, and have left a mark in history and in the surface of the Earth. The level of background radiation in the air increased, and this had an effect on the production of steel, so that steel produced since 1945 has had elevated levels of radioactivity. This can be a problem for sensitive instruments, so there was a demand for steel called low background steel, which was made before the trinity tests.

The Bessemer process pumps air through the iron to remove impurities. shropshirehistory.com

The production of steel is done with the Bessemer process, which takes the molten pig iron and blasts air through it. By pumping air through the steel, the oxygen reacts with impurities and oxidizes, and the impurities are drawn out either as gas or slag, which is then skimmed off. The problem is that the atmospheric air has radioactive impurities of its own, which are deposited into the steel, yielding a slightly radioactive material. Since the late 1960s steel production uses a slightly modified technique called the BOS, or Basic Oxygen Steelmaking, in which pure oxygen is pumped through the iron. This is better, but radioactive material can still slip through. In particular, we’re interested in cobalt, which dissolves very easily in steel, so it isn’t as affected by the Bessemer or BOS methods. Sometimes cobalt is intentionally added to steel, though not the radioactive isotope, and only for very specialized purposes.

Recycling is another reason that modern steel stays radioactive. We’ve been great about recycling steel, but the downside is that some of those impurities stick around.

Why Do We Need Low Background Steel?

Imagine you have a sensor that needs to be extremely sensitive to low levels of radiation. This could be Geiger counters, medical devices, or vehicles destined for space exploration. If they have a container that is slightly radioactive it creates an unacceptable noise floor. That’s where Low Background Steel comes in.

A person is placed into a low background steel container with sensitive equipment to measure the radioactivity of the body, which may be near the background level. Photo from orau.org

So where do you get steel, which is a man-made material, that was made before 1945? Primarily from the ocean, in sunken ships from WWII. They weren’t exposed to the atomic age air when they were made, and haven’t been recycled and mixed with newer radioactive steel. We literally cut the ships apart underwater, scrape off the barnacles, and reuse the steel.

Fortunately, this is a problem that’s going away on its own, so the headline is really only appropriate as a great reference to a popular movie. After 1975, testing moved underground, reducing, but not eliminating, the amount of radiation pumped into the air. Since various treaties ending the testing of nuclear weapons, and thanks to the short half-life of some of the radioactive isotopes, the background radiation in the air has been decreasing. Cobalt-60 has a half-life of 5.26 years, which means that steel is getting less and less radioactive on its own (Cobalt-60 from 1945 would now be at .008% of original levels). The newer BOS technique exposes the steel to fewer impurities from the air, too. Eventually the need for special low background steel will be just a memory.

Oddly enough, steel isn’t the only thing that we’ve dragged from the bottom of the ocean. Ancient Roman lead has also had a part in modern sensing.

WTF are Ground Loops?

These magical creatures crop up out of nowhere and fry your electronics or annoy your ear holes. Understanding them will doubtless save you money and hassle. The ground loop in a nutshell is what happens when two separate devices (A and B) are connected to ground separately, and then also connected to each other through some kind of communication cable with a ground, creating a loop. This provides two separate paths to ground (B can go through its own connection to ground or it can go through the ground of the cable to A and then to A’s ground), and means that current may start flowing in unanticipated ways. This is particularly noticeable in analog AV setups, where the result is audio hum or visible bars in a picture, but is also sometimes the cause of unexplained equipment failures. Continue reading “WTF are Ground Loops?”

PCB Design Guidelines to Minimize RF Transmissions

There are certain design guidelines for PCBs that don’t make a lot of sense, and practices that seem excessive and unnecessary. Often these are motivated by the black magic that is RF transmission. This is either an unfortunate and unintended consequence of electronic circuits, or a magical and useful feature of them, and a lot of design time goes into reducing or removing these effects or tuning them.

You’re wondering how important this is for your projects and whether you should worry about unintentional radiated emissions. On the Baddeley scale of importance:

  • Pffffft – You’re building a one-off project that uses battery power and a single microcontroller with a few GPIO. Basically all your Arduino projects and around-the-house fun.
  • Meh – You’re building a one-off that plugs into a wall or has an intentional radio on board — a run-of-the-mill IoT thingamajig. Or you’re selling a product that is battery powered but doesn’t intentionally transmit anything.
  • Yeeeaaaaahhhhhhh – You’re selling a product that is wall powered.
  • YES – You’re selling a product that is an intentional transmitter, or has a lot of fast signals, or is manufactured in large volumes.
  • SMH – You’re the manufacturer of a neon sign that is taking out all wireless signals within a few blocks.

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Tools of the Trade – Thermoforming

Chances are good that you’ve already lost some blood to thermoforming, the plastics manufacturing process that turns a flat sheet of material into an unopenable clamshell package, tray inside a box, plastic cup, or leftover food container.  Besides being a source of unboxing danger, it’s actually a useful technique to have in your fabrication toolchest. In this issue of Tools of the Trade, we look at how thermoforming is used in products, and how you can hack it yourself.

The process is simple; take a sheet of plastic material, usually really thin stuff, but it can get as thick as 1/8″, heat it up so that it is soft and pliable, put it over a mold, convince it to take all the contours of the mold, let it cool, remove it from the mold, and then cut it out of the sheet. Needless to say, there will be details.

https://commons.wikimedia.org/wiki/File:Thermoforming_animation.gif
https://commons.wikimedia.org/wiki/File:Thermoforming_animation.gif

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