Coffee, Conspiracy, And Citizen Science: An Introduction To Iodometry

October 30, 2017 by 40 Comments

I take coffee very seriously. It’s probably the most important meal of the day, and apparently the largest overall dietary source of antioxidants in the United States of America. Regardless of whether you believe antioxidants have a health effect (I’m skeptical), that’s interesting!

Unfortunately, industrially roasted and ground coffee is sometimes adulterated with a variety of unwanted ‘other stuff’: corn, soybeans, wheat husks, etc. Across Southeast Asia, there’s a lot of concern over food adulteration and safety in general, as the cost-driven nature of the market pushes a minority of vendors to dishonest business practices. Here in Vietnam, one of the specific rumors is that coffee from street vendors is not actually coffee, but unsafe chemical flavoring agents mixed with corn silk, roasted coconut husks, and soy. Local news reported that 30% of street coffee doesn’t even contain caffeine.

While I’ve heard some pretty fanciful tales told at street side coffee shops, some of them turned out to be based on some grain (bean?) of truth, and local news has certainly featured it often enough. Then again, I’ve been buying coffee at the same friendly street vendors for years, and take some offense at unfounded accusations directed at them.

This sounds like a job for science, but what can we use to quantify the purity of many coffee samples without spending a fortune? As usual, the solution to the problem (pun intended) was already in the room:

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Scary LEGO chocolate dispensing machine

Mechanical Marvel Trades Courage For Chocolate

October 30, 2017 by 4 Comments

When we see what [Jason Allemann] does with LEGO, we wonder why more one-offs aren’t made this way. This time he’s made a Halloween mechanical marvel that will surely scare more kids than anything else they’ll encounter on their rounds — so much so that many may even decline the chocolate it dispenses. Who wouldn’t when to get it you have to reach over an animatronic skeleton hand that may grab you while a similarly mechanized spider may lunge onto your hand.

The chocolate dispensing, the hand and the spider are all animated using four motors, a LEGO Mindstorms EV3 brick to control them, and a touch sensor. When a kid presses a pumpkin attached to the touch sensor, the next chocolate candy is lowered by gravity onto a conveyor belt and carried forward to the awaiting child. That much is automatic. At the discretion of [Jason] and his partner [Kristal], using an infrared remote control and sensor, they can activate the skeleton hand and the lunging spider at just the right moment. We’re just not sure who they’ll choose to spare. It is Halloween after all, and being scared is part of the fun, so maybe spare no one? Check out the video below and tell us if you’d prefer just the treat, or both the trick and treat.

We do have to wonder if there’s any project that can’t benefit from LEGO products, even if only at the prototype stage or to help visualize an idea. As a small sample, [Jason]’s also made a remote-controlled monowheel and an actual working printer along with a Morse key telegraph machine to send it something to print.

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Surfboard Industry Wipes Out, Innovation Soon Follows

October 30, 2017 by 84 Comments

For decades, Gordon Clark and his company Clark Foam held an almost complete monopoly on the surfboard blank market. “Blanks” are pieces of foam with reinforcing wood strips (called “stringers”) in a rough surfboard shape that board manufacturers use to make a finished product, and Clark sold almost every single one of these board manufacturers their starting templates in the form of these blanks. Due to environmental costs, Clark suddenly shuttered his business in 2005 with virtually no warning. After a brief panic in the board shaping industry, and a temporary skyrocketing in price of the remaining blanks in existence, what followed next was rather surprising: a boom of innovation across the industry.

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PCB Tesla Coil Is Perfect Desk Toy

October 30, 2017 by 43 Comments

A Tesla coil easily makes it to the top spot on our list of “Mad Scientist” equipment we want for the lab, second only to maybe a Jacob’s Ladder. Even then, it’s kind of unfair advantage because you know people only want a Jacob’s Ladder for that awesome sound it makes. Sound effects not withstanding, it’s Tesla coil all the way, no question.

Unfortunately, winding your own Tesla coil is kind of a hassle. Even on relatively small builds, you’ll generally need to setup some kind of winding jig just to do the secondary coil, which can be a project in itself. So when [Daniel Eindhoven] sent his no-wind Tesla coil into the tip line, it immediately got our attention.

The genius in his design is that the coils are actually etched into the PCB, completely taking the human effort out of the equation. Made up of 6 mil traces with 6 mil separation, the PCB coil manages to pack a 25 meter long, 160 turn coil into an incredibly compact package. As you might expect, such a tiny Tesla coil isn’t exactly going to be a powerhouse, and in fact [Daniel] has managed to get the entirely thing running on the 500 mA output of your standard USB 2.0 port.

In such a low-power setup, [Daniel] was also able to replace the traditional spark gap pulse generator with a PIC18F14K50 microcontroller, further simplifying the design. An advantage of using a microcontroller for the pulse generator is that it’s very easy to adjust the coil’s operating frequency, allowing for neat tricks like making the coil “sing” by bringing its frequency into the audible range.

For those looking to build their own version, [Daniel] has put the PCB schematic and firmware available for download on his site. He also mentions that, in collaboration with Elektor magazine, he will be producing a kit in the near future. Definitely something we’ll be keeping an eye out for.

Incidentally, this isn’t the first time [Daniel] has demonstrated his mastery of high voltage. He scared impressed us all the way back in 2010 with his 11,344 Joule capacitor bank, perfect for that laptop-destroying rail gun you’ve been meaning to build.

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This Drone Can Fly, Swim, And Explode….. Wait, What?

October 30, 2017 by 17 Comments

You’ve probably heard of micro-drones, perhaps even nano-drones, but there research institutions that shrink these machines down to the size of insects. Leading from the [Wiss Institute For Biologically Inspired Engineering] at Harvard University, a team of researchers have developed a miniscule robot that — after a quick dip — literally explodes out of the water.

To assist with the take off, RoboBee has four buoyant outriggers to keep it near the water’s surface as it uses electrolysis to brew oxyhydrogen in its gas chamber. Once enough of the combustible gas has accumulated — pushing the robot’s wings out of the water in the process– a sparker ignites the fuel, thrusting it into the air. As yet, the drone has difficulty remaining in the air after this aquatic takeoff, but we’re excited to see that change soon.

Looking like a cross between a water strider and a bee, the team suggest this latest version of the RoboBee series  — a previous iteration used electrostatic adhesion to stick to walls — could be used for search and rescue, environmental monitoring, and biological studies. The capacity to transition from aerial surveyor, to underwater explorer and back again would be incredibly useful, but in such a small package, it is troublesome at best. Hence the explosions.

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Scratch That SDR!

October 29, 2017 by 16 Comments

When you think of a software defined radio, what language might you consider reaching for to create the software part of the equation? C? C++, maybe?

How about Scratch?

“What, Scratch as in the visual programming language aimed at young people?”, we hear you cry incredulously. It’s not exactly the answer you’d expect for an SDR, but thanks to [Andrew Back]’s work there is now ScratchRadio, a set of Scratch extensions for software defined radio. Why on earth do this? The aim is to lower the barrier to entry for software defined radio as far as possible, and to place it in a learning environment such as Scratch seems an ideal way to achieve that.

Of course, Scratch itself isn’t powerful enough for the heaviest of heavy lifting, so in reality this is a Scratch wrapper for a LuaRadio backend. It was created with the LimeSDR Mini in mind, but given that LuaRadio is not specific to that hardware we’d expect it to work with other SDRs such as the ever-popular RTL chipset TV sticks. It gives an owner of a Raspberry Pi 3 the ability to experiment with SDR coding without the need for a huge level of experience, and that to our mind can only be a good thing.

If you fancy trying ScratchRadio, you can find the code in its GitHub repository, and take it from there. Meanwhile we covered LuaRadio last year, so if Scratch is a little basic for you and GNU Radio too advanced, give it a try.

Radio icon: [Sakurambo], (CC BY-SA 3.0).

Scratch cat logo: MIT Media Lab.

Water Slide + Ferris Wheel = SlideWheel

October 29, 2017 by 30 Comments

This might be German engineering at its funnest. [Wiegand Maelzer GmbH] have created a new type of amusement park ride that combines the thrill of a water slide with the gentle revolutions of a Ferris wheel.

Inspired by the wish of a young Swiss boy in 2012, the whimsical feat of engineering known as the SlideWheel was realized this year. This is isn’t quite the giant sloshing drowning machine it appears to be on first blush, though. It begins and ends at the same shallow pool, where three- and four-person rafts are lifted into the ride by conveyor belt. What happens next is difficult to describe. It’s easier just to watch the first-person video below that demonstrates the pendulum-like motion that comes from floating while rotating.

SlideWheel moves at a modest 3 RPM, though this can be adjusted. Travel speed through the tube maxes out at 40 KPH/ 25 MPH, but will vary depending on the raft’s location, the position of the wheel, and gravity. The ride can handle up to three rafts at a time and delight 720 people per hour. A trip through the tube lasts a mere two minutes, but all those who’ve tried it say the experience seems much longer. [Wiegand Maelzer] have already received a few orders and are working on a dry version for malls and indoor amusement parks.

Not enough of an engineering feat, you say? Here’s a car-juggling robot.

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