DIY Pyrography Power Supply

Ever wanted to try your hand at wood burning? If you already threw away your first soldering iron—you know the one: plugged straight in to the wall, no temperature control, came with a thick piece of tin foil to rest it on—don’t despair. Pyrography pens don’t cost that much. The variable power supply they plug into, though: that’s another story. Those cost more than they probably should.

[td0g] took the plunge into pyrography a while back, and wanted to build his own controller from an old ATX power supply. Why not? It should be more than capable of doing the job. Even the most heavy-duty pyrography pens only draw 10A, and the 3.3V line showed to be rated for 30A. All [td0g] had to do was add a PWM with a MOSFET and a ‘Tiny85.

The project nearly became Fail of the Week fodder after [td0g] saw huge voltage spikes across the MOSFET. A 47kΩ resistor took care of those, and a heat sink salvaged from the junk bin will prolong the transistor’s life. [td0g] added a push button that cycles through five heat settings, and an LED to show the status. After that, all he had to do was add a male RCA input to connect the pens he already has.

Okay, so you wouldn’t be caught dead dropping money on some fancy power supply for this new hobby. Don’t want to buy pens, either? Roll your own from a plasma arc lighter.

Bluetooth Bedroom Clock!

When [decino]’s old bedroom clock finally bit the dust, he built himself a new one from scratch for fun and functionality.

Initially, he wanted to solder Adafruit NeoPixel lights onto four prototype boards, using a mini-USB for power and a DS1307 to keep the time. However, after soldering the board for the first digit and realizing that carrying on with the other three would be a huge pain, he switched to etching the boards instead — a far more efficient solution. In keeping with this time-saving mindset, he added a Bluetooth module that would allow him to update the clock from his phone whenever the DS1307 started dropping minutes or whenever daylight savings time is in effect.

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Modern Strongman Games Test Your Speed Instead

Step right up! What would a Makerfaire be without some carnival games? And being a Makerfaire, they could of course be modernized versions. In [avishorp]’s case, he made a series of games that test your speed and look very much like the old strongman game, aka high striker or strength tester.

In the strongman game, you smash a lever with all your might using a hammer. A puck on the other end of the lever then shoots up a tower, hopefully high enough to hit a bell, winning you a prize. In [avishorp]’s games the puck, tower and bell are all replaced with an LED strip. In the swipe game, the faster you swipe your hand sideways over two optical proximity sensors, the higher the LEDs light up. In the drum game, the speed with which you drum on a rubber disk with embedded accelerometer, the higher the LEDs light up. The chase and response games both involve buttons that you have to rapidly hit, to similar effect.

For the brains, each game is controlled by an Adafruit Trinket board. [Avishorp] chose to use the PlatformIO IDE instead of the Arduino IDE to write them, preferring its modern editor, but he didn’t like that it doesn’t print and that it doesn’t tell you the final file size. The latter issue caused him to overwrite the bootloader, something that he understandably considered a major inconvenience.

Check out his page for more details, Fritzing diagrams, links to code, and all game videos. Meanwhile we’ve included clips of the drum and swipe games below.

And if it’s more carnival games you’re looking for, how about this adult-sized Sit ‘n Spin made using a rear differential and axle assembly out of an old car or truck. Or maybe you prefer something less likely to make you woozy, in which case you can try fishing with the Bass Master 3000.

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USB + μC = Peril?

You hear about people finding USB drives and popping them into a computer to see what’s on them, only to end up loading some sort of malware onto their computer. It got me to thinking, given this notorious vulnerability, is it really a great idea to make electronics projects that plug into a computer’s USB port? Should I really contribute to the capitulation-by-ubiquity that USB has become?

A of couple years ago I was working on an innocuous project, a LED status light running off of USB. It ran off USB because I had more complicated hopes for it–some vague notion about some kind of notification thing and also it was cool to have access to 5 V right from the ‘puter. This was about the time that those little RGB LEDs connected to USB were all the rage, like blink(1), which raised $130,000 on Kickstarter. I just wanted to make a status light of some sort and had the parts, so I made it.

My version was a small rectangular PCB from OSHPark packing a Tiny85, with a 10 mm RGB LED providing pretty much all of the functionality — no spare pins broken out. Honestly, for the amount of code on it, even the Tiny85 was overpowered. I recall thinking at the time, could my creation be misused for evil? Could some wicked programmer include malware alongside my LED-lighting Arduino sketch?

It’s absurd, of course. My meager engineering skills ought not interest anyone. On the other hand, couldn’t some heartless poltroon, the hardware equivalent of a script kiddie, make my creation into a malware-spewing Typhoid Mary of a project? It has always been the realistic consequence of building anything–that it could be misused. I’d be thrilled to the point of giddiness if someone remade one of my projects into something cool, but I’d really hate for a USB light I designed to turn into some vector into someone’s computer. But how much of that is my responsibility?

If you think I’m the only one who thinks this, go to SparkFun or Adafruit and count all of the boards with microcontrollers and USB A male plugs. Even the tiny boards like the Huzzah and Gemma use USB cables, rather than plugging directly into the computer. Granted, they are microcontrollers that realistically would be connected to a project and it might not be possible to physically move them into position and plug them in. Also requiring a charging cable does not in any way make a microcontroller board work any differently than one plugged right into the computer. I’m left wondering if I’m spazzing out over nothing, and there’s nothing we can do about our tendency to treat any electronic gizmo with a shiny case as being safe to plug into the same computer we use to pay bills.

If there is no data transfer taking place, and I’m just getting power, wouldn’t it be enough to disable (or not connect) the data pins of the USB on the circuit board? Or maybe we really have no business connecting a data connection to a microcontroller if we’re not reflashing the chip with fresh code–think I’m paranoid? Maybe you should just get power from a wall wart and leave the USB cord in the drawer. It’s one thing to urge our friends and family to steer clear of mystery plugs, but as engineers and tinkerers, do we not owe the community the benefit of our knowledge?

Of course, Hackaday contains numerous examples of USB projects, including canary for USB ports, tips on protecting your ports with two microcontrollers, a guide to stopping rubber ducky attacks, and removing security issues from untrusted USB connections. Also, has anyone used the USB condom?

Friends, let me know your thoughts on the subject. Am I a freak to steer clear of USB-powered project like my dumb LED? Leave your comments and weigh in with your opinions.

Mini Tetris Game Packs a Tiny85

[dombeef] originally built pocketTETRIS as a Father’s Day gift for his Tetris-loving pops. However, having finished the project he’s decided to share it with the universe, and it’s looking rather sweet.

He made the game the smallest he could make, with size limitations imposed by a 0.96” OLED display, the coin-cell battery pack, and his desire for a durable 3D-printed case. It uses a ATtiny85 for the brains, mounted on a custom PCB that [dombeef] designed in KiCad. The Arduino code was modified from Andy Jackson’s ATtinyArcade code, giving it three-button capability instead of two. [dombeef] has details on the project page on as well as 3D-design and PCB-design files on the project’s code repository on GitHub.

We’ve published a fair number of Tetris posts in the past, including skyscraper Tetris, playing Tetris on a soldering iron, and Tetris in 446 bytes. What’s the smallest Tetris you’ve seen?

Making Synths out of Audio Cassettes

8bit Mixtapes are simple Arduino-based sound and beat generators based on ATtiny 84s and 85s and designed fit inside old audio cassettes, or at least be about that size. Founded by [Dusjagr], [Ucok] and [Lyok], and including participants from around the globe, 8bit Mixtapes are small synthesizers that play one-line algorithmic symphonies, simple sound generators that work off of a single line of code.

The project has been going on for a number of years, with several different iterations released over the years–the most recent is the Mixtape NEO, released about a month ago that features audio bootloading and a row of NeoPixel LEDs. It’s well documented and fully open source, with a code repository and wiki. The arty PCBs look great as well!

8bit Mixtapes are a natural project for electronics students to tackle. An ATtiny85 with two pots and two buttons? Pretty simple, and the musical payoff makes it a cinch for one-day workshops. The code simplicity makes it easy to modify the software as well.

Quirky synths are Hackaday’s bag, including one we published previously that controls a hexagonal matrix of LEDs.

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The Smart Pen

“Ugh. You mean I have to press down on the pen’s button to open it? Gross.” In this day-and-age when we can swipe on our phones and do voice recognition, there seems no reason we should have to press a button. How antiquated. So [Marek Baczynski] modernized his pen for swiping and voice control. It’s also sure to get all the kids back to working on their penmanship.

Seriously though, not all hacks have to be serious. [Marek] and [Ghlargh] added a servo to activate the button, and then [Marek] added Bluetooth to control the servo. After writing a phone app, he was able to swipe down to open it and down again to close it. Then, after some prompting from Redditers he added voice control from his laptop. We think he could have done a more professional job with the way he attached the pen to the laptop, perhaps he could have 3D printed something instead of just using tape, or maybe made something using CNC or a laser cutter. An important hack such as this deserves as much. Now he need only say “Computer. Open pen.” and the tedious task is taken care of. Seeing is believing so check it out in the video below.

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