Ask Hackaday: Who Wants An All DC House?

September 4, 2014 by Will Sweatman 268 Comments

Sometimes when working on a righteous hack, we get goosebumps while watching our code execute faster than we could ever possibly comprehend. Seeing the pixels of the LCD come alive, hearing the chatter of relays and the hum of fans…it’s an amazing thing what electricity can do. And it is equally amazing when you realize that it all started one hundred and thirty five years ago, when [Thomas Edison] changed the world forever with the first practical electric light bulb.

That bulb was lit by a Direct Current – the same thing that runs the computer you’re reading this article on. The same thing that runs many of the hacks you read about here on Hack a Day, and almost all electronic devices in your house. But somewhere in the mix must exist a device that changes the Alternating Current from your wall outlet to the needed DC. Why? Why is it that we transport electricity as AC only to convert it to DC in our homes? You might answer:

“This argument was played out in the War of Currents back in the 1880’s.”

Indeed, it was. But that was a long time ago. Technology has changed. Changed so much to the point that the arguments in the War of Currents might no longer be valid. Join us after the break, where we rehash these arguments, and explore the feasibility of an all DC environment.

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Extrinsic Motivation: An Open, Modular Effects Pedal

September 4, 2014 by Brian Benchoff 18 Comments

Microcontrollers and Arduinos are cool and all, but dealing only in the digital domain does have its limitations. In fact, most of your electron heroes didn’t begin their electronics career by blinking pins on digital outputs; they were solely in the analog domain with their radios and, yes, guitar effects pedals.

[Josh]’s entry for The Hackaday Prize was by far the most analog project of the entire contest. It’s an open source effects pedal that takes advantage of the modular design of the most popular pedals in history.

A good number of the famous circuits for turning an electric guitar into an aural experimentation are based on small circuit modules, packaged and repackaged again until the desired tone is achieved. [Josh] wants to pack these modules separately on different boards, specifically shields, although no Arduino is used, so any sound can be created.

Already [Josh] has done some research to determine what circuits and circuit modules to clone. The list should be fairly familiar to anyone with a pedalboard – Tube Screamers, Fuzz Faces, Big Muffs, and Phase 90s are at the top of the list. He may not get to the complicated digital effects like pitch shifters and digital delays, but it’s still a great project for experimentation.

You can see [Josh]’s project video below.

This project is an official entry to The Hackaday Prize that sadly didn’t make the quarterfinal selection. It’s still a great project, and worthy of a Hackaday post on its own.

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Tricking Tinder With A 3D Printed Finger

September 3, 2014 by Matt Terndrup 19 Comments

Online matchmaking has taken the internet by storm as mobile dating applications like Tinder attempt to take the work out of locating a soul mate. As of mid-2014, Tinder is rumored to have around 10 million daily active users making it a prime target for automated spam bots. The real spammers surely use coded attacks, but this robot is a fun example of a hardware-based attack. [Andrew] built it to be an automatic heart-shaped, button presser.

The device began as a single finger robot-hand project that was inspired by ‘InMoov’, which as their website states is “the first life-size humanoid robot you can 3D print and animate.” An Arduino Uno and servo motor laid the foundation for the system. After which, the joints of the 3D printed finger were assembled in place so that a touchscreen stylus could be attached. Once coded, the little robot was able to ‘like’ a new profile every 4 seconds. This adds up to approximately 900 likes per hour.

The project is cute, and shows one way that fake profiles can be elevated on the Tinder platform. An article written on Symantec’s blog describes a few other instances of spammers flirting with you via the Android app. This post is a continuation of an article released a year prior, yet Tinder has not addressed the issues relating to fake profiles since then.

Let’s try to focus in on the good. With a bit of additional ingenuity, this device could be transformed into a love searching robot that could choose between people. Get a camera hooked up with a face-recognition program, and add some user preferences so that the robot isn’t just hitting ‘like’ over and over, and we might be able to get some interesting research done. Still, it feels like it would be better to go meet people face-to-face.

Check out the video of the bot in action after the break, then let us know what other silly things you could do by targeting different apps.

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THP Semifinalist: The Moteino

September 3, 2014 by Brian Benchoff 16 Comments

One of the apparent unofficial themes of The Hackaday Prize is the Internet of Things and home automation. While there were plenty of projects that looked at new and interesting ways to turn on a light switch from the Internet, very few took a good, hard look at the hardware required to do that. [Felix]’s Moteino is one of those projects.

The Moteino is based on the Arduino, and adds a low-cost radio module to talk to the rest of the world. The module is the HopeRF RFM12B or RFM69. Both of these radios operate in the ISM band at 434, 868, or 915 MHz. Being pretty much the same as an Arduino with a radio module strapped to the back, programming is easy and it should be able to do anything that has been done with an ATMega328.

[Felix] has been offering the Moteino for a while now, and already there are a few great projects using this platform. In fact, a few other Hackaday Prize entries incorporated a Moteino into their design; Plant Friends used it in a sensor node, and this project is using it for texting and remote control with a cell phone.

The project featured in this post is a semifinalist in The Hackaday Prize.

Goliath And The Rough Road To Space

September 3, 2014 by Adam Fabio 49 Comments

No one said the road to The Hackaday Prize would be easy. Many of us have been following [Peter McCloud] as he vies for the Hackaday Prize with Goliath – A Gas Powered Quadcopter. [Peter] literally hit a snag on Monday: his own belts.

Peter had hoped to be performing tied down hover tests by Monday afternoon. Weather and a set of fouled spark plugs conspired against him though. After fighting with engine issues for the better part of a day, [Peter’s] 30 horsepower Briggs & Stratton engine finally roared to life. Then all hell broke loose.

[Peter] only let the engine run a couple of seconds before cutting the ignition. In his own words, “Things were running good until the engine was shutoff. At this point one of the belt started losing tension.”

While the tight new engine was quickly losing RPM, the propeller and belt system still had quite a bit of inertia. As the video after the break shows, the belts started flapping and caught on the propeller blades. The front right prop tip caught the double-sided toothed belt, pulling it up and over the propeller. The other end of that same belt lives on the right rear prop. It too caught a propeller blade, snapping the composite blade clean off its hub. The bent steel pulley axles are a testament to the forces at work when things went wrong.

[Peter] isn’t giving up though. He has a plan to add belt guides and a one way bearing to the engine’s crankshaft. The one way bearing will allow the rotor system to overspeed the engine when throttle is reduced. The same bearings are commonly used on R/C helicopters to facilitate autorotation landings.

We want to see all 50 Hackaday Prize semifinalists succeed, so if you have any ideas to help with the rebuild, head over to Goliath’s Hackaday.io page and let [Peter] know!

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Retrotechtacular: Time For Coffee

September 3, 2014 by Kristina Panos 24 Comments

If you ask us, it’s almost always a good time for coffee. In the spotlight this week is an educational/promotional film made by A&P, who started in the 1800s as with a chain of shops offering coffee and tea. By the 1950s, they were operating full self-serve grocery stores with a trail of shuttered mom and pop operations in their wake.

This is the story of coffee as it goes from the nursery to the field to the shelves of your local A&P. It covers the growing, cultivation, and distribution of coffee from South American crops that at the time covered more than one million square miles of Brazil alone.

Coffee trees leave the nursery at two years old and are planted in nutrient-rich red soil. Two to three years later, they bear their first crop. Coffee blossoms appear first, and the fruit ripens over the next 8-9 months. Skilled workers pick the berries by hand. We are told that the average tree produces one pound of roasted coffee per year.

The day’s harvest is collected, weighed, and bagged for further production. The fruits are crushed to remove each bean from its red jacket. Then, the beans are washed and spread out in the sun for 8-10 days. They are frequently rotated so they dry evenly. The dried coffee is packed in bags and sent into the city.

At a warehouse, the coffee is inspected, sorted, and graded. Bags are stamped with the coffee’s country of origin and intended destination before going to the seaport. A very important step happens here. As each bag walks by on the shoulders of a worker, another guy stabs it to get a sample of the beans. The on-site A&P officials take over at this point and do their own inspections, sending samples to the US. Here, the coffees are roasted and taste tested for both strength and flavor from a giant lazy Susan full of porcelain cups.

The film takes a brief detour to tell us that the great cities of Latin America were built upon the labors of coffee exportation. We see a montage of vistas, skylines, and shorelines, which bring it back to the subject of shipping the coffee to various ports of call. At the dock, bags are tumbled onto large nets to be loaded on the ship. As coffee is susceptible to moisture, special care is taken to avoid the ill effects of traveling out of the tropics.

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[Ben Krasnow] Hacks A Scanning Electron Microscope

September 3, 2014 by Adam Fabio 32 Comments

[Ben Krasnow] is quite possibly the only hacker with a Scanning Electron Microscope (SEM) collection. He’s acquired a JEOL JSM-T200, which was hot stuff back in the early 1980’s. [Ben] got a great deal, too. He only had to pay shipping from Sweden to his garage. The SEM was actually dropped during shipment, but thankfully the only damage was a loose CRT neck plug. The JSM-T200 joins [Ben’s] homemade SEM, his DIY CT scanner, the perfect cookie machine, and a host of other projects in his lab.

The JSM-T200 is old tech; the primary way to store an image from this machine is through a screen-mounted Polaroid camera, much like an old oscilloscope. However, it still has a lot in common with current SEMs. In live video modes, an SEM can only collect one or two reflected electrons off a given section of a target. This creates a low contrast ghostly image we’ve come to associate with SEMs.

Attempting to fire more electrons at the target will de-focus the beam due to the electrons repelling each other. Trying to fire the electrons from higher voltages will just embed them into the target. Even SEMs with newer technology have to contend with these issues. Luckily, there is a way around them.

When “writing to photo”, the microscope switches to a slow scan mode, where the image is scanned over a period of a minute. This slower scan gives the microscope extra time to fire and collect more electrons – leading to a much better image. Using this mode, [Ben] discovered his microscope was capable of producing high-resolution digital images. It just needed a digital acquisition subsystem grafted on.

Click past the break to see how [Ben] modernized his microscope!

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