Pinewood Derby Scale Measures CG

If you suffer from nostalgia, you might remember carving a block of wood into a car, adding some wheels, and racing it against other contestants in a pinewood derby. Today’s derby is decidedly high tech though, and we were impressed with this car scale that also figures out the car’s center of gravity.

Based on an Arduino, of course, along with a pair of HX711 load cells. Why a pair? That’s how the device measures the center of gravity is by weighing the front and rear of the car separately.

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This Classy But Chaotic Gear Clock Keeps You Guessing

There are a lot of ways to tell time, but pretty much all of them involve some sort of sequential scale — the hands sweeping across the face of an analog clock comes to mind, as does the incremental changes of a digital clock. Clocks are predictable by their very nature, and therefore somewhat boring.

This nonsequential gear clock aims to break that predictability and make for a timepiece that’s just a little bit different. It’s the work of [Tony Goacher], who clearly put a lot of work into it and pulled out nearly every tool in the shop while doing it. He started with a laser-cut plywood prototype to get the basics worked out — a pair of nested rings with internal gear teeth, each hanging on a stepper-driven pinion. The inner ring represents hours and the outer minutes, with the numbers on each randomly distributed — more or less, since no two sequential numbers are positioned more than five seconds of rotation apart.

The finished version of the clock is rendered in brass, acrylic, hardwood, and a smattering of aluminum, with a case reminiscent of the cathedral radios of yore. There are some really nice touches, like custom-made brass screws, a CNC-engraved brass faceplate with traditional clock art, and a Latin inscription on the drive cog for the hours ring that translates roughly to “Time rules all.” When we looked that up we found that “tempus rerum imperator” is the motto of the Worshipful Company of Clockmakers, the very existence of which we find pleasing in the extreme.

The clock runs through its initialization routine in the brief video below. We’re not sure we’d want this on our nightstand, but it’s certainly a unique and enjoyable way to show the passage of time. It sort of reminds us of this three-ringed perpetual calendar, but just a bit more stochastic.

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Parallax Update Hack Chat

Join us on Wednesday, August 28th at noon Pacific for the Parallax Update Hack Chat with Chip and Ken Gracey!

For a lot of us, our first exposure to the world of microcontrollers was through the offerings of Parallax, Inc. Perhaps you were interested in doing something small and light, and hoping to leverage your programming skills from an IBM-PC or an Apple ][, you chanced upon the magic of the BASIC Stamp. Or maybe you had a teacher who built a robotics class around a Boe-Bot, or you joined a FIRST Robotics team that used some Parallax sensors.

Whatever your relationship with Parallax products is, there’s no doubting that they were at the forefront of the hobbyist microcontroller revolution. Nor can you doubt that Parallax is about a lot more than BASIC Stamps these days. Its popular multicore Propeller chip has been gaining a passionate following since its 2006 introduction and has found its way into tons of projects, many of which we’ve featured on Hackaday. And now, its long-awaited successor, the Propeller 2, is almost ready to hit the market.

The Gracey brothers have been the men behind Parallax from the beginning, with Chip designing all the products and Ken running the business. They’ll be joining us on the Hack Chat to catch us up on everything new at Parallax, and to give us the lowdown on the P2. Be sure to stop be with your Parallax questions, or just to say hi.

join-hack-chatOur Hack Chats are live community events in the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Wednesday, August 28 at 12:00 PM Pacific time. If time zones have got you down, we have a handy time zone converter.

Click that speech bubble to the right, and you’ll be taken directly to the Hack Chat group on Hackaday.io. You don’t have to wait until Wednesday; join whenever you want and you can see what the community is talking about.