We’ve all tangled with unwelcome plant life at one point or another. Whether crabgrass infested your lawn, or you were put on weeding duty in your grandfather’s rose patch, you’ll know they’re a pain to remove, and a pain to prevent. For farmers, just imagine the same problem, but scaled up to cover thousands of acres.
Dealing with weeds typically involves harsh chemicals or excessive manual labor. Lasers could prove to be a new tool in the fight against this scourge, however, as covered by the BBC.
If you ever work with a circuit that controls a decent amount of current, you will often encounter a FET – a Field-Effect Transistor. Whether you want to control a couple of powerful LEDs, switch a USB device on and off, or drive a motor, somewhere in the picture, there’s usually a FET doing the heavy lifting. You might not be familiar with how a FET works, how to use one and what are the caveats – let’s go through the basics.
Here’s a simple FET circuit that lets you switch power to, say, a USB port, kind of like a valve that interrupts the current flow. This circuit uses a P-FET – to turn the power on, open the FET by bringing the GATE signal down to ground level, and to switch it off, close the FET by bringing the GATE back up, where the resistor holds it by default. If you want to control it from a 3.3 V MCU that can’t handle the high-side voltage on its pins, you can add a NPN transistor section as shown – this inverts the logic, making it into a more intuitive “high=on, low=off”, and, you no longer risk a GPIO!
This circuit is called a high-side switch – it enables you to toggle power to a device at will through a FET. It’s the most popular usecase for a FET, and if you’re wondering more about high-side switches, I highly recommend this brilliant article by our own [Bil Herd], where he shows you high-side switch basics in a simple and clear way. For this article, you can use this schematic as a reference of how FETs are typically used in a circuit.
What if you could tweak the recipe on ice cream to keep it frozen at higher temperatures? The idea comes from massive conglomerate Unilever. Among other things, the brand owns a wide variety of ice cream brands, from Ben & Jerry’s to the Magnum and Cornetto lines. Instead of running freezers at the industry standard of -18 °C (0°F), the company is experimenting with upping the temperature to -12 °C (10 °F) instead.
First off, you’d save a lot of electricity. Thanks to the way the industry works, the company actually owns the vast majority of the three million or so display freezers that are used to sell its stock to customers. Running at a higher temperature could slash the freezer’s energy use by 20% to 30%, according to the company’s calculations. The company also estimates that the energy used by these freezers makes up around 10% of its total greenhouse gas footprint, so it’s better for the environment too.
Of course, there’s savvy commercial reasons behind the idea. Unilever had noticed its ice cream sales dropping in 2022. The company believes this was in part due to retailers unplugging their freezers earlier than usual as winter approached, due to high energy bills. If the company’s freezers aren’t humming, they’re doing less business. If shaving down the freezer’s energy use helps retailers keep them plugged in and the lights on, that’s a net bonus to the company’s bottom line. It could also make their freezers unhospitable places for rival products, giving them an edge in the marketplace.
But this is all business intrigue. Let’s instead take a deeper look at ice cream.
Off-the-shelf stock parts are the blocks from which we build mechanical projects. And while plenty of parts have dedicated uses, I enjoy reusing them in ways that challenge what they were originally meant for while respecting the constraints of their construction. Building off of my piece from last time, I’d like to add to your mechanical hacking palette with four more ways we can re-use some familiar off-the-shelf parts. Continue reading “The BSides: More Curious Uses Of Off-the-shelf Parts”→
The Baader-Meinhof effect is the common name for what scientists call frequency illusion. Suppose you are watching Star Trek’s Christopher Pike explain how he makes pasta mama, and you’ve never heard of it before. Immediately after that, you’ll hear about pasta mama repeatedly. You’ll see it on menus. Someone at work will talk about having it at Hugo’s. Here’s the thing. Pasta mama was there all along (and, by the way, delicious). You just started noticing it. We sometimes wonder if that’s the deal with Morse code. Once you know it, it seems to show up everywhere.
Gen. Hideki Tojo in custody in 1947
One of the strangest places we’ve ever heard of Morse code appearing is the infamous case of Tojo’s teeth. If you don’t remember, General Hideki Tojo was one of the main “bad guys” in the Pacific part of World War II. In particular, he is thought to have approved the attack on Pearl Harbor, which started the American involvement in the war globally. Turns out, Tojo would be inextricably tied to Morse code, but he probably didn’t realize it.
The Honorable Attempt
At the end of the war, the US military had a list of people they wanted to try, and Tojo was near the top of their list of 40 top-level officials. As prime minister of Japan, he had ordered the attack that brought the US into the war. He remained prime minister until 1944, when he resigned, but the US had painted him as the face of the Japanese enemy. Often shown in caricature along with Hitler and Mussolini, Tojo was the face of the Japanese war machine to most Americans.
In Allied propaganda, Tojo was one of the “big three”
When Americans tried to arrest him, though, he shot himself. However, his suicide attempt failed. Reportedly, he apologized to the American medics who resuscitated him for failing to kill himself. Held in Sugamo Prison awaiting a trial, he requested a dentist to make him a new set of dentures so he could speak clearly during the trial.
This edition’s community build comes from the Yes They Could, But Should They Have? file. Well, I ultimately say yes, this is intriguing. Redditor [dj_edit] looked at the venerable Model M and thought, this buckling-spring masterpiece can yet be improved upon. Yeah! Well, to each their own. I must say that it does sound great, especially with the solenoid feedback enabled via rotary encoder. Just check out the typing test.
To be clear, this is essentially a new keyboard that fits inside a Model M case, but that alone is quite a feat, especially if you consider the curvature of the backplate. Because of this hurdle, [dj_edit] went with 1 mm FR4 for the switch PCB, which is a nice compromise of sturdiness and flexibility.
Underneath those stunning reproduction keycaps are Kailh box white switches, which are pretty chonky-sounding on their own. But turn on that sweet solenoid action and you really get noisy.
Those box whites are sitting in hot-swap sockets, a design decision that kind of made things difficult because of the curvature. [dj_edit] ended up using an acrylic plate that gets bent to match the curvature by the switches themselves.
The Vintage Computer Festival East took place last weekend at the InfoAge Science and History Museum in New Jersey, and by any metric you care to use, it was a phenomenal success. Everyone you spoke with, from the the exhibitors and attendees, to the veteran volunteers who put this incredible show together, all said the same thing: they’d never seen a turnout like this before.
Of course, such success is not without cost. The exhibit rooms were so packed that moving through them was a challenge, the line to get food or browse the consignment area occasionally stretched outside the building, and at one point the event’s electronic payment system buckled under the pressure.
Some things are worth the wait.
Yet even the folks who waited the better part of an hour to rummage through boxes of dusty treasures, only to find themselves left standing with armfuls of heavy gear they couldn’t pay for until the technical issues were resolved couldn’t really complain. I should know, I was one of them. It would be like going to a concert and getting upset that the music was too loud — the event was advertised as a festival, and that’s exactly what it was.
No matter where you went, you’d find throngs of excited people who were eager to chat about the golden age of computing. So even if you were stuck in a long line, or had to step outside of the exhibit area to get some fresh air, you were always in excellent company. Seeing such a large and diverse number of people come out for what’s ultimately a niche event was exceptionally gratifying. At the end of the day, if the price we have to pay for this kind of community response is a few long lines and tight squeezes, it’s well worth it.
Each time I cover an event like this for Hackaday, I do so with the caveat that there’s really no substitute for being there in person. No matter how many articles you read and YouTube recaps you watch, you’ll never be able to see all the things you would have had you been able to walk the show floor yourself. It’s a bit like exploring the Moon or Mars: remotely controlled robots are capable of capturing terabytes of data and beaming it back to Earth, but even still, there’s the potential to learn so much more by putting boots on the ground.
The same is true of VCF East 2023 — what I bring you here is just the tip of the iceberg in terms of what was on display at this year’s event. On the other hand, you have the advantage of being able to peruse these images without having to stand in line. Is it worth the trade? Only you can be the judge of that. But for my money, I’ll gladly get back in line when VCF East 2024 rolls around.
Here’s a simple FET circuit that lets you switch power to, say, a USB port, kind of like a valve that interrupts the current flow. This circuit uses a P-FET – to turn the power on, open the FET by bringing the GATE signal down to ground level, and to switch it off, close the FET by bringing the GATE back up, where the resistor holds it by default. If you want to control it from a 3.3 V MCU that can’t handle the high-side voltage on its pins, you can add a NPN transistor section as shown – this inverts the logic, making it into a more intuitive “high=on, low=off”, and, you no longer risk a GPIO!
