Mickey’s Big Timer Makes Glider Competitions Better

There’s plenty of obscure sports in the world. Many of them could benefit from bespoke equipment like scoring displays, but are too obscure to support commercial efforts in this regard. Radio controlled glider competitions fit into just this category. This led a man named [Mickey] to develop what he calls Mickey’s Big Timer, to aid in the running of such events.

Glider events run outdoors in full sunlight, so the system uses big bright LED matrix displays to show its timing information. The system, built around the STM32 Discovery platform, uses several of the microcontroller boards to drive several displays as well as the main controller which handles timing. It also packs in an audio system for issuing instructions to competitors. It can also display pilot names as well as instructions such as when competitors should land at the end of a heat.

Some code is available on Github for those interested in how it all works. Word around the RC forums has it that [Mickey] built several systems, some of which ended up as far afield as New Zealand where they helped run many successful glider contests over the years.

We’ve seen plenty of scoreboard projects over the years; a little portable one could be useful for adding some spice to your pickup neighbourhood games. Video after the break.

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Should Have Used A Vacuum Tube 555

“You should have used a 555” has become a bit of a meme around these parts lately, and for good reason. There seems to be little that these ubiquitous chips can’t be used for, and in a world where code often substitutes for hardware, it’s easy to point to instances where one could have just used a simple timer chip instead.

Definitely not in the meme category, though, is this overkill vacuum tube 555 timer. It comes to us via [David Lovett], aka [Usagi Electric], who has lately caught the “hollow state” electronics bug and has been experimenting with all sorts of vacuum tube recreations of circuits we’re far more used to seeing rendered in silicon than glass. The urge to replicate the venerable 555 in nothing but vacuum tubes is understandable, as it uses little more than a pair of comparators and a flip-flop, circuits [David] has already built vacuum tube versions of. The only part left was the discharge transistor; a pentode was enlisted to stand in for that vital function, making the circuit complete.

To physically implement the design, [David] built a large PCB to hold the 18 vacuum tubes and the handful of resistors and capacitors needed. Mounted on eight outsized leads made from sheet steel, the circuit pays homage to the original 8-pin DIP form of the 555. The video below shows the design and build process as well as testing of all the common modes of operation for the timer chip.

You can check out more of our coverage of [David]’s vacuum tube adventures, which started with his reverse-engineering of an old IBM logic module. And while he did a great job explaining the inner workings of the 555, you might want to take a deeper dive into how the venerable chip came to be.

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Arduino Wannabe Should Have Used A 555. Oh Wait, It Does.

It’s a little known secret that when the Hackaday writers gather in their secret underground bunker to work on our plans for world domination, we often take breaks to play our version of the corporate “Buzzword Bingo”, where paradigms are leveraged and meetings circle back to loop in offline stakeholders, or something like that. Our version, however, is “Comment Line Bingo”, and right in the middle of the card is the seemingly most common comment of all: “You should have used a 555,” or variations thereof.

So it was with vicious glee that we came across the Trollduino V1.0 by the deliciously named [Mild Lee Interested]. It’s the hardware answer to the common complaint, which we’ll grant is often justified. The beautiful part of this is that Trollduino occupies the same footprint as an Arduino Uno and is even pin-compatible with the microcontroller board, or at least sort of. The familiar line of components and connectors sprout from the left edge of the board, and headers for shields line the top and bottom edges too. “Sketches” are implemented in hardware, with jumpers and resistors and capacitors of various values plugged in to achieve all the marvelous configurations the indispensable timer chip can be used for. And extra points for the deliberately provocative use of Comic Sans in the silkscreen.

Hats off to [Lee] for a thoroughly satisfying troll, and a nice look at what the 555 chip can really do. If you want a more serious look at the 555, check out this 555 modeled on a breadboard, or dive into the story of the chip’s development.

Bare-Metal STM32: Blinky And The Secret Of Delay Functions

One of the very first examples for an MCU or SoC usually involves the famous ‘Blinky‘ example, where an LED is pulsed on and off with a fixed delay. This is actually a lot more complicated than the ‘Pushy‘ example which we looked at in the first installment of this series. The reason for this is that there’s actually quite a story behind a simple call to delay() or its equivalent.

The reason for this is that there are many ways to implement a delay function on a microcontroller (MCU), each of which comes with their own advantages and disadvantages. On an STM32 MCU, we get to choose between essentially an active delay (while loop), one implemented using the SysTick timer and using one of the peripheral timers. In the latter two cases we also have to use interrupts.

In this article we’ll take a look at all three approaches, along with their advantages and disadvantages.

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Over-Engineered Single Button Timer

Feature creep is typically something to be avoided, since watching a relatively simple project balloon into a rat’s nest of complexity often leads to ineffective, or even abandoned, projects. On the other hand, if you can maintain a tight focus, it’s not always a bad thing. [cbm80Amiga] shows us how to drill down and add specific features in this single-button timer without losing focus on what the original project was all about.

The timer is based on an Arduino Pro Mini and an HX1230 LCD with a simple piezo speaker for audible alerts. A single button controls operation of the timer, with short presses incrementing each digit and long presses moving on to the next digit. Controlling button presses this finely is a project in its own, but then [cbm80Amiga] moves on to other features such as backlight control, low power modes which allow it to operate for around two years on a single battery charge, preset times for various kitchen uses, and different appearance settings.

Honestly we aren’t sure how you could cram any more features on this timer without fundamentally altering the designed simplicity. It doesn’t fall into the abyss of feature creep while being packed with features, and it’s another example of how keeping things simple is often a recipe for success.

Thanks to [Hari] for the tip!

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Helmet Decal Charger Keeps Them Ready To Glow

When firefighters are battling a blaze, it’s difficult for them to find each other in the smoky darkness. To help stand out they wear glow-in-the-dark decals on their helmets, but since they spend so much of their down time stowed away in a dark locker, they don’t always have a chance to charge up.

[Bin Sun]’s firefighter friend inspired them to build a portable charging system that can stuff those helmet decals full of photons in a matter of minutes. Although phosphorescent materials will charge in any light, they charge the fastest with ultraviolet light. This uses a pair of UV LED strips controlled by an off-the-shelf programmable timer, and powered with an 18-volt drill battery stepped down to 12 V. The timer makes it easy for [Bin Sun]’s friend to schedule charge times around their shifts, so the battery lasts as long as possible while keeping the decals ready to glow.

We love that [Bin Sun] seems to have thought of everything. The light strips are nestled into 3D-printed holders that also house small magnets. This makes it easy to position the lights on either side of the locker so both the front and back decals soak up the light.

Phosphorescent materials are great as a reusable display medium, especially when they’re designed to look like Nixie tubes.

Handwashing Timer Makes Sure The Suds Stay On Long Enough

“Twinkle, Twinkle, Little Star”? How we wonder why you’d resort to singing a ditty to time your handwashing when you can use your social isolation time to build a touch-free electronic handwash timer that the kids — and you — might actually use.

Over the last few months, pretty much everyone on the planet has been thrust into strange, new, and oftentimes scary practices to limit the spread of the SARS-CoV-2virus and the disease it causes, COVID-19. Judging by the number of people we’ve seen leaving public restrooms without a visit to the washbasin before the outbreak began — and sadly all too often since — we collectively have a lot of work to do in tightening up our handwashing regimens. Time on target and plenty of friction are the keys to that, and [Denis Hennessy]’s “WashTimer” aims to at least help you out with the former. His build is as simple as can be: an Arduino driving an LED matrix when a proximity sensor fires. Wave your dirty paws in front of the unit as you start to scrub up, and the display goes through a nicely animated 20-second countdown, at which time it’s safe to rinse off.

[Denis] purposely made this design as simple and as customizable as possible. Perhaps you’ve got a Neopixel ring lying about rather than the LED matrix, or maybe an ultrasonic sensor would work better for you. Be creative and take this design where it needs to go to suit your needs. We can’t stress enough that handwashing is your number one defense; if you don’t need to moisturize your hands at least three times a day, you’re probably not washing often or long enough. And 20 seconds is way longer than you think it is without a prompt.

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