How To Put The ‘Pro’ In Prototype

April 29, 2018 by Kristina Panos 5 Comments

It’s easy to get professional-quality finishes on your prints and prototypes if you take the right steps. In the final installment of his series about building with Bondo, product designer [Eric Strebel] shows us how it’s done no matter what the substrate.

How does he get such a smooth surface? A few key steps make all the difference. First, he always uses a sanding block of some kind, even if he’s just wrapping sandpaper around a tongue depressor. For instance, his phone holder has a round indent on each side. We love that [Eric] made a custom sanding block by making a negative of the indent with—you guessed it—more Bondo and a piece of PVC. The other key is spraying light coats of both primer and paint in focused, sweeping motions to allow the layers to build up.

If you need to get the kind of surface that rivals a baby’s behind, don’t expect to prime once, paint once, and be done with it. You must seek and destroy all imperfections. [Eric] likes to smooth them over with spot putty and then wet sand the piece back to smooth before applying more primer. Then it’s just rinse and repeat with higher grits until satisfied.

There’s more than one way to smooth a print, of course. Just a few weeks ago, our own [Donald Papp] went in-depth on the use of UV resin.

Continue reading “How To Put The ‘Pro’ In Prototype” →

Former Smoker Now Pats Pockets For Motivation

April 24, 2018 by Kristina Panos 13 Comments

It’s hard to quit smoking. Trust us, we know. Half the battle is wanting to quit in the first place. Once you do, the other half is mostly fighting with yourself until enough time goes by that food tastes better, and life looks longer.

[Danko] recently quit smoking. And because idle hands are Big Tobacco’s tools, he kept himself busy through those torturous first few days by building a piece of pocket-sized motivation. This little board’s main purpose is to help him root for himself by showing the time elapsed since his final cigarette, the number of cigarettes he has avoided, and all the money he’s saved since then. At the press of a button, he can reflect on the exact moment he took the plunge into Cold Turkey Lake.

Sure, there are apps that’ll do the same thing. But anyone who’s ever tried to quit smoking knows how important it is to stay busy every minute while your brain deals with the lack of toxins. It runs on an ATtiny85 and a DS1307 RTC chip. Looks to us like [Danko] adapted a board from a different project, and we love it when that’s a possibility.

Not a smoker? Good for you. The next hardest thing humans motivate themselves to do is exercise. That’s a lifelong battle that can definitely be improved with some gamification.

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Émilie Du Châtelet: An Energetic Life

April 24, 2018 by Kristina Panos 19 Comments

Émilie du Châtelet lived a wild, wild life. She was a brilliant polymath who made important contributions to the Enlightenment, including adding a mathematical statement of conservation of energy into her French translation of Newton’s Principia, debunking the phlogiston theory of fire, and suggesting that what we would call infrared light carried heat.

She had good company; she was Voltaire’s lover and companion for fifteen years, and she built a private research institution out of a château with him before falling in love with a younger poet. She was tutored in math by Maupertuis and corresponded with Bernoulli and Euler. She was an avid gambler and handy with a sword. She died early, at 41 years, but those years that she did live were pretty amazing. Continue reading “Émilie Du Châtelet: An Energetic Life” →

Remote Control Of Clocks Is Easy As Pi

April 22, 2018 by Kristina Panos 16 Comments

[Fatjedi007] recently acquired three programmable boxing gym-type clocks to help his developmentally disabled clients manage their time. The plan was to have timers of varying lengths fire at preset times throughout the day, with the large displays providing a view from anywhere. Unfortunately, the clocks were not nearly as programmable as he needed them to be.

Since he’d spent enough money already, [Fatjedi007] turned to the power of Raspberry Pi to devise an affordable solution. Each clock gets a Pi Zero W and a simple IR transmit/receive circuit that operates using LIRC. The clocks came with remote controls, so it was just a matter of re-programming them. From LIRC, he wrote some scripts with SEND_ONCE and schedules the timers with a cron job. No need to get out the ladder—he can program all of them from his chair over VNC.

He does have one problem, though, and that’s getting the Zeros to set themselves over NTP with static IPs. Do you have any suggestions? Put ’em in the comments and help a Jedi out.

LIRC is pretty handy for anything you want to control remotely, like a stereo system.

Roomba-Riding Beer Butlers Will Serve Us All

April 21, 2018 by Kristina Panos 7 Comments

[Josh] isn’t one to refuse a challenge, especially when robots are involved. The latest dare from friends and family? Build a beer robot that can bring beverages at everyone’s beck and call.

The build consists of two main parts: the refrigerated cooler and the butler part, which comes courtesy of a Roomba Discovery from a fellow roboticist. [Josh] is basing the design on double-walled and insulated restaurant coolers. He built the refrigerated beverage hold from two stainless steel trash cans, sized an inch or so apart in diameter, and filled the gap with expanding foam insulation. He then cut away several inches from the bottom of the liner can to make room for the cooling unit, reinstalled the drip tray, and made a [airflow-allowing platform] by drilling a bunch of holes in an antimicrobial plastic cutting board.

At first, he tried a Peltier unit from an electric Igloo cooler, but that doesn’t work as well as [Josh] hoped, so he’s redesigning the can to use a mini fridge compressor. This meant making custom evaporator and condenser coils from copper tubing to match the compressor’s load spec. Go through [Josh]’s build logs over on IO and you’ll get a free mini-course on expanding foam and refrigeration.

[Josh] is currently working on some different butler modes for this robot. These run the gamut from simply sitting nearby with cold beverages and opening with the wave of a hand to doing voice-triggered beverage butler-ing at everyone’s beck and call. We applaud his efforts thus far and will be following this one with great ~~thirst~~ interest to see how he handles navigation and voice control.

DIY Drill-Powered Water Pump

April 17, 2018 by Kristina Panos 14 Comments

Whether you need to pump water out of your basement this spring, or just want to have fun shooting water around in the yard this summer, here’s a way to build a pump instead of buying one. This is a simple but ingenious build, and [NavinK30] did everything shy of machining his own hardware and making his own tools. Well, it looks as if he might have made that drill.

As you’ll see in his how-to after the break, this centrifugal pump is mostly acrylic, PVC, and fasteners. [Navin] cut two sides and a base for the paddles from acrylic, and joined them with a heat-formed sidewall made of PVC. We love that he cut and bent his own paddles from sheet metal. These are bolted to a round piece of acrylic that attaches to the outside with a long hex bolt. A ball bearing mounted on the drill side allows the pump to churn freely as long as the bolt is chucked into the drill, and the hose clamp is tight enough to hold down the trigger.

Have an extra drill, but don’t need to pump water? Add a camping stove and use it to power a small-batch coffee roaster.

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Beatrice Tinsley And The Evolution Of Galaxies

April 17, 2018 by Kristina Panos 10 Comments

It seems almost absurd now, but cosmologists once assumed that galaxies of a given type were all the same and didn’t change. Because of this assumption, galaxies were used as a redshift or light-based yardstick to measure distances in the universe. But what if some galaxies were intrinsically redder than others? Little to no thought was given to their origins, compositions, or evolution until Beatrice Tinsley came along.

Beatrice saw galaxies as changing bodies of stars. She believed that they grew, evolved, and died because they’re made of stars, and that’s what their star populations did. To lump all galaxies together and use them as a standard candle was an oversimplification. Beatrice created the first computer model of a galaxy to prove her point and in doing so, she founded the field of galaxy evolution.

If you’ve never heard of Beatrice, don’t feel bad. Just as her career was really beginning to take off, she developed cancer and died shortly after her 40th birthday. Though her life was short, her influence on cosmology is long-reaching. Continue reading “Beatrice Tinsley And The Evolution Of Galaxies” →