Eco Friendly Space-Fuel

February 14, 2016 by Gerrit Coetzee 64 Comments

If you’d like to risk blowing your fingers off for a good cause this week, look no further than [M. Bindhammer]’s search for an eco-friendly rocket fuel. [M. Bindhammer] predicts the increasing use of solid rocket boosters in the future. We’re into that. For now, rocket launches are so few and far between that the pollution doesn’t add up, but when we’re shipping consumer electronics to the moon and back twice a day, we might have a problem.

The most common solid rocket fuel emits chlorine gas into the atmosphere when burned. [Bindhammer] is exploring safe ways to manufacture a eutectically balanced and stabilized fuel compromised of sugar or sugar-alcohol, and potassium nitrate. If you watch home chemistry videos for fun on the weekend like us, [Bindhammer] goes through all his thinking, and even spells out the process for duplicating his fuel safely in a lab.

He’s done a lot of work. The resulting fuel is stable, can be liquid or solid. It has a high ignition temperature, but as you can see in the video after the break. Once ignited. It goes off like rocket fuel.

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Puzzle Alarm Clock Gets Couple Up In The Morning

February 13, 2016 by Gerrit Coetzee 24 Comments

[BrittLiv] and her boyfriend got in one too many fights about who set the alarm. It’s the only argument they seem to repeat. So, true to her nature as an engineer, she over-engineered. The result was this great puzzle alarm clock.

The time displayed on the front is not the current time. Since the argument was about alarm times in the first place, [BrittLiv] decided the most prominent number should be the next alarm. To hear the time a button (one of the dots in the colon) must be pressed on the front of the clock. To set the alarm, however, one must manually move the magnetized segments to the time you’d like to get up. Processing wise, for a clock, it’s carrying some heat. It runs on an Intel Edison, which it uses to synthesize a voice for the time, news, weather, and, presumably, tweets. It sounds great, check it out after the break.

All in all the clock looks great, and works well too. We hope it brought peace to [BrittLiv]’s household.

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Manned Multicopter Project Undaunted By Crash

February 13, 2016 by Gerrit Coetzee 97 Comments

We have to be impressed by [amazingdiyprojects] who completely totaled their manned multi-copter build, which has been spanning over eight videos. He explained the crash in video number eight and is right back at it, learning from the recent mistakes.

When you get right down to it, this is as dangerous as this seems. However, a giant multicopter is probably the easiest flying machine for a hobbyist to build. It’s an inefficient brute-force approach, but it sure beats trying to build a helicopter from scratch. This machine is a phenomenally un-aerodynamic chair on a frame that has a lot in common with the lunar rover; with engines on it. Simple.

There are a lot of approaches to this. One of the crazier ones is this contraption with a silly amount of electric motors. [amazingdiyprojects] went with eight gasoline engines. We’re really interested in his method for controlling the rpm of each engine and dealing with the non-linearity of the response from a IC engine throttle. Then feeding that all back into what is probably the exact same electronics from a regular diy drone.

Honestly, we’re surprised it worked, and we can’t wait for him to finish it so we can see him zooming around in his danger chair. Videos after the break.

Thanks [jeepman32] for the tip!

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Flexible Phototransistor Will Make Everything Subtly Better In The Future

February 13, 2016 by Gerrit Coetzee 23 Comments

University of Wisconsin-Madison is doing some really cool stuff with phototransistors. This is one of those developments that will subtly improve all our devices. Phototransistors are ubiquitous in our lives. It’s near impossible to walk anywhere without one collecting some of your photons.

The first obvious advantage of a flexible grid of phototransistors is the ability to fit the sensor array to any desired shape. For example, in a digital camera the optics are designed to focus a “round” picture on a flat sensor. If we had a curved surface, we could capture more light without having to choose between discarding light, compensating with software, or suffering the various optical distortions.

Another advantage of the University’s new manufacturing approach is the “flip-transfer” construction method they came up with. They propound that their method produces a vastly more sensitive device. The sensing silicon sits on the front of the assembly without any obstructing material in front; also the metal substrate it was built on before flipping is reflective; also increasing the sensitivity.

All in all very cool, and we can’t wait for phone cameras, with super flat lenses, infinite focus, have no low light capture issues, and all the other cool stuff coming out of the labs these days.

Glitching Square Wave Clock Is Designed To Confuse

February 12, 2016 by Gerrit Coetzee 25 Comments

[Voja Antonic] has built a clock that tells the time in binary with square waves, and trolls the uninitiated in electronics.

The clock itself is very attractive. If you look closely you can see the circuitry backlit behind the dot LED matrix display. The whole thing is housed in a nicely folded steel case. RGB LEDs are used to good effect to highlight some additionally obfuscating circuit schematics. The workmanship is very top notch, and we would gladly host such an object on our desks.

The clock’s standard time telling mode is three sets of square waves showing the binary values for the hours, minutes, and seconds. Every now and then the clock will glitch out. The waves will distort. The colors will change. And every now and then, tantalizingly, the alpha-numeric time will show up for just a split second, before returning to those weird squiggles again.

We’ve seen a whole slew of binary clocks before. This one, for instance. But the waveform display makes us feel just that little bit more at home — it’s just like we’re sitting in front of our oscilloscope.

New Efficiency Standards For Wall Warts In The US

February 12, 2016 by Gerrit Coetzee 190 Comments

The common household wall wart is now under stricter regulation from the US Government. We can all testify to the waste heat produced by many cheap wall warts. Simply pick one at random in your house, and hold it; it will almost certainly be warm. This regulation hopes to save $300 million in wasted electricity, and reap the benefits, ecologically, of burning that much less fuel.

We don’t know what this means practically for the consumer. Will your AliExpress wall warts be turned away at the shore now? Will this increase the cost of the devices? Will it make them less safe? More safe? It’s always hard to see where new regulation will go. Also, could it help us get revenge on that knock-off laptop adapter we bought that go hot it melted a section of carpet?

However, it does look like most warts will go from a mandated 50-ish percent efficiency to 85% and up. This is a pretty big change, and some hold-out manufacturers are going to have to switch gears to newer circuit designs if they want to keep up. We’re also interested to hear the thoughts of those of you outside of the US. Is the US finally catching up, or is this something new?

How A Professional Resin Caster Duplicates Parts

February 11, 2016 by Gerrit Coetzee 14 Comments

[Gregg Eshelman] reproduces plastic parts for antique car restorations for a living; likewise, he’s very good at it. Greg always chimes in with helpful hints whenever we post about resin casting. Shown above is a lens for a car turn signal. Manufactured in 1941, having [Gregg] cast a few copies is an easy option for replacing the rare part.

[Gregg] uses a similar method to us, but it is easy to see that he has done it more and his process has been refined by lots of experience. We really liked how he avoids using expensive foam core by wrapping cardboard in packing tape, or using the kind that has a plastic coating on it; the kind most retail packaging is made out of. He also has better techniques for keying the part to be manufactured, and prepping difficult geometry between different mold halves. It also never would have occurred to us to use Dremel cutting disks to cut the sprues and air vents in the silicone, a surprisingly tricky material to cut precisely with a knife.

It’s always nice when a professional takes time to write about their processes for the hobbyist trying to emulate it. We hope [Gregg] writes more tutorials, and continues to contribute in the comment section. If you have your own fabrication techniques to share we’d love to hear about it on the tips line.