We’ve seen quite a few clocks that write the time out with a pen or marker. If you think about it, this really isn’t a great solution; every whiteboard marker will dry out in a day or two, and even if you’re using a pen, that’s still eventually going to run out of ink.
[ekaggrat] wanted a drawing clock that didn’t have these problems, and after taking a look at a magnetic drawing board, was struck with inspiration. The result is a clock that will perpetually write the time. It’s a revision of one of his earlier builds and looks to be much more reliable and mechanically precise.
A clock that writes time needs some sort of surface that won’t degrade, but can be written to over and over again. Whiteboards and glass won’t work, and neither will anything with ink. The solution to this problem was found in a ‘magnetic writing board’ or a Magna Doodle. These magnetic writing boards have a series of cells encapsulating iron filings. Pass a magnet over one side of the board, and a dot of filings appear. Pass a magnet over the opposite side of the board, and the filings disappear.
[ekaggrat]’s time-writing robot consists of a small Magna Doodle display, a robotic arm controlled by two stepper motors, and two solenoids on the end of the arm. The kinematics come from a helpful chap on the RepRap forums, and with the ATmega644 and two stepper drivers, this clock can write the time by altering the current flowing through two solenoids.
A video is the best way to experience this project, and you can check that out below.
Filed under: clock hacks
Meet Marty. He’s a pumpkin that has been fitted out with a moving eyes, tongue and an expression of malevolent glee. You would probably assume that this is all driven by servos, right? Nope: Marty is driven by an old-fashioned crank mechanism, designed and built by [Ben Brandt].
He wanted to make something that could be driven by a hand crank. Of course, there is nothing stopping you from throwing a motor on the back to drive the mechanism, but [Ben] wanted the internals to be fireproof so he could light it with a candle. His mechanism, built from old bits of wire and sheet metal, is not flammable or adversely affected by heat like a motor and power supply would be. He succeeded admirably, and he has also done an excellent job of documenting the process to providing handy tips on creating a mechanical pumpkin-based monstrosity.
Those hackers down with a little electronic wet work you should start building their LED-integrated Jack-O-Lantern now. These things take a lot of time turn out.
Filed under: Holiday Hacks, toy hacks
You can’t be bothered to sign up for a free parts.io account? Fine. You also don’t want to sign in each time you need to look up a component? Got it. You’ve made your point and the folks over at parts.io have made it so.
When the parts.io electronic component search engine was opened up for public use we covered it and gave you the rundown. Some of our readers left comments about things they were unhappy with regarding the parts.io system. Surprisingly, signing in was the most frequently voiced concern. It looks like your complaints were not taken lightly and you no longer have to register with the site to unlock all the parametric search data. There is still some added value to having an account like saving parts to a list for later use or you could get involved by joining the parts.io community on the forum.
Now we just need a parts search that knows what we want without having to actually choose parameters.
Full Disclosure: Parts.io is produced by Supplyframe Inc. Hackaday is an Editorially Independent part of Supplyframe.
Filed under: news
It is hard enough to beat computers at games like chess. Now robotics engineers at the Ishikawa Watanabe Laboratory in Japan have created a janken robot that wins every time (if you didn’t know, janken is the Japanese name for rock-paper-scissors). How can it win every time? Easy. It cheats.
The janken robot evolved through three different versions. In the first version, the robotic hand would note the human player’s hand with a high-speed camera and then move the hand to a winning counter play with about a 20 millisecond delay. In the second version, the delay was greatly reduced.
However, in the third version, the robot uses a scanning technique to capture an entire field of view and determines what play the human is making. Again, a winning counter play is instantly produced by the robotic hand.
We actually covered an earlier version of the janken robot in 2012. You can contrast the two videos to see how it has evolved over time. If you want to go old school, you can even play janken against a computerized glove. Not quite as cool, but maybe easier to build.
The only question we had: If you are going to go through all the trouble to build this robot, why wouldn’t it play rock paper scissors Spock Lizard?
Filed under: robots hacks
Synaptics is probably best known for making the touchpads found on laptops. But the company also develops touchscreen technology for notebooks, tablets and smartphones and one of the company’s latest touch controllers offers pressure-sensitive Force Touch capabilities. The new Synaptics 3700 Series touch controller is currently in mass production, and supports Synaptics ClearForce and SideTouch (edge […]
Synaptics launches force touch solution for smartphones is a post from: Liliputing
Sure, Siri, Cortana, and Google’s voice search let you talk to your smartphone and listen to it talk back. But you know what your phone probably can’t do? Walk. Fortunately, Sharp is on it. The Japanese consumer electronics company has unveiled a new smartphone called the RoboHon. But it’s not just a phone. It’s also a […]
Video arcades may be a thing of the past, but they’re still alive, well and were ready to play at this year’s World Maker Faire. The offerings weren’t old favorites, all were brand new games many being shown for the first time like the long-awaited VEC9. The Hall of Science building was filled with cabinets and no quarters were necessary, all were free-play.
Death By Audio Arcade was there in force with games like Particle Mace and Powerboat Italia ’88. Our personal favorite was Nothing Good Can Come of This. [Michael P. Consoli] devised a simple game: Two players in an empty room. A bullet drops from a hole in the ceiling, followed by a gun shortly thereafter. What happens next is up to the players. The simple graphics and gameplay give this title its charm. [Michael] was showing off a new stand-up cabinet for the game this year. He built the entire thing himself, working until the wee hours before load-in at Maker Faire.
[Batsly Adams], [Todd Bailey], and [Mike Dooley] teamed up to create what may be the first new vector arcade in decades. VEC9 has been teased for over 2 years. They’ve finally wrapped this game up and showed it off at the faire. VEC9 started with an old
Asteroids vector monitor found by [Batsly].
Vector monitors are closer to oscilloscopes than raster scan TV’s. Digital to analog converters create drive voltages which steer an electron beam where it needs to go. The result is a high-resolution display that is very good at drawing straight lines – and lots of them. The video system was created using a Xilinx Spartan-3E FPGA coded in VHDL. The game logic itself is coded in good old-fashioned C. The vector monitor isn’t the only display on this game though – there is also a monochrome raster CRT, which displays status information to the game player. A display system this epic would need a control system to match. The team delivered with an authentic tank control yoke, complete with working wing switches.
If you can’t tell from the images, VEC9 is all about Mother Russia. The premise is that VEC9 is a dead hand system created in 1984. Since it can no longer contact controllers, the system has assumed the USSR was destroyed by a strike from the USA. It’s up to the player to take revenge. Check out the release trailer for a real taste of this game.
[NYC Resistor] didn’t sit this Maker Faire out either. Their arcade project was a full body-immersive game called Semaphore Hero. Much like Guitar Hero, this game requires the player to follow an on-screen pattern, this time with semaphore flags rather than guitar notes.
Players wear a life vest festooned with a blue LED. Semaphore flags complete with green and red LEDs are used to spell out the semaphore alphabet. A camera hidden behind a dark filter analyzed the position of the LEDs and determined if the player was in the correct position for each letter. The game was coded in C# using the Unity engine. The NYC Resistor team was running it on an older MAC mini using Mono. This game was tough! Our best score was only 11 out of 26.
Filed under: classic hacks, video hacks
Visit a foreign language website in the Chrome browser on your Android phone, and the browser will offer to translate it into your preferred language. But what happens when you fire up a mobile app that has foreign-language content? Nothing… until now. Google has announced that Android 6.0 adds Google Translate support to many apps, allowing […]
Markus Gritsch shared his LiFePO4 charger project in the forum:
Since I really like using LiFePO4 AA and AAA batteries in some of my projects, I finally gave in and built a dedicated charger for them.
Previously I used a lab power supply to mimic the constant current/constant voltage charging curve, which worked also fine. But after seeing Patrick Van Oosterwijck nifty LiFePO4wered/USB™, I thought it would be a bit more convenient to charge these batteries using USB.
Microsoft’s new Surface Pro 4 tablet may be thinner, lighter, more powerful, and have a slightly larger, higher resolution display than last year’s model. But the Surface Pro 3 is still cheaper… especially if you buy one on sale. Right now Microsoft is offering models for $699 and up. That’s $100 off the list price, and […]
Sony’s been going through some major restructuring in recent years. While the company’s phones and TVs are still well regarded, Sony spun off its VAIO PC division as a separate company a little while ago. Now the company is spinning off is semiconductor business. That’s the division of Sony responsible for producing image sensors like those […]
Sony spins off semiconductor (and image sensor) business is a post from: Liliputing
Every Tuesday we give away two coupons for the free PCB drawer via Twitter. This post was announced on Twitter, and in 24 hours we’ll send coupon codes to two random retweeters. Don’t forget there’s free PCBs three times a every week:
- Hate Twitter and Facebook? Free PCB Sunday is the classic PCB giveaway. Catch it every Sunday, right here on the blog
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- Check out how we mail PCBs worldwide video.
- We’ll contact you via Twitter with a coupon code for the PCB drawer.
- Limit one PCB per address per month please.
- Like everything else on this site, PCBs are offered without warranty.
The philosopher in the street, who has not suffered a course in quantum mechanics, is quite unimpressed by the [Einstein-Podolsky-Rosen] correlations. He can point to many examples of similar correlations in everyday life. The case of Bertlmann’s socks is often cited. Dr. Bertlmann likes to wear two socks of different colours. Which colour he will have on a given foot on a given day is quite unpredictable. But when you see that the first sock is pink you can be already sure that the second sock will not be pink. Observation of the first, and experience with Bertlmann, gives the immediate information about the second. There is no accounting for tastes, but apart from that there is no mystery here. And is this [Einstein-Podolsky-Rosen] business just the same?
John Bell began his now famous paper with the above paragraph. The Bell Inequality started off like so many other great theories in science – as a simple thought experiment. Its conclusions were not so simple, however, and would lead the way to the end of Einstein’s idea of local hidden variables, and along with it his hopes for a deterministic universe. In this article, we’re going to look at the Bell inequality in great detail. Our guide will be a chapter from Jim Baggots’ The Quantum Story, as it has one of the best descriptions of Bell’s theory I’ve ever read.
Before we start – a quick review:
Niels Bohr’s Quantum Theory says reality is probabilistic in nature. Einstein disagreed, and spent the latter part of his life trying to prove Bohr wrong. It culminated into a thought experiment known as the EPR paradox. This is where Einstein introduced his local hidden variables theory. But John Bell was able to prove that it was possible to show that local hidden variables could not account for all the predictions of quantum theory. Einstein was never able to recover from this defeat and technology would eventually advance enough to test Bell’s theory, proving Einstein wrong. This is the story about how John Bell achieved this remarkable feat.How To Make A Local Hidden Variable Theory
Let us consider a fragmented pair of hydrogen atoms whose total spin is equal to zero. We send both atoms speeding away in opposite directions. We then measure the spin of one of the atoms using a [Stern-Gerlach] device – which is just two magnets with opposite poles resting very close to each other.Stern-Gerlach setup to measure spin.
When a spinning particle, or in our case a hydrogen atom, passes between the poles, the direction of the spin can be determined by the direction the atom is deflected. We say an atom with a “spin up” is one that is deflected to the north magnetic pole and designated “+”. Likewise, an atom with an opposite spin will be in a “spin down” state, and will be deflected to the south magnetic pole. Its designation is “-“.
Back to the case of our pair of fragmented hydrogen atoms – when we measure the spin of one we can determine what the spin of the other is, as they have to be opposite. Einstein would say that the spin of each of the atoms was determined at the moment of fragmentation… that there is some type of hidden variable within each of the atoms that determines the spin. Remember that quantum theory says the spin of the two fragmented atoms cannot be known until one is measured. And somehow when one spin is measured, the other atom must know to take the opposite spin. This is the heart of the EPR paradox.The Quantum Story, Fig 20
Now, lets look at this local hidden variable idea the way John Bell did. Let us suppose that each atom has a little hidden dial deep within one of its many subatomic particles. A dial that has yet to be discovered. The dial can point in any direction from 0 to 360 degrees. Each of our hydrogen atoms has one of these dials, and when they are paired, the dials point in opposite directions. When the atoms become unpaired, the dials become fixed, as pictured in the figure on the left.
Now let’s pass our atoms through the [Stern-Gerlach] spin detector. With our newfound knowledge of the hidden dial, we find that the atoms get deflected to whatever direction the dial is pointing. Such that if the dial in the atom is anywhere in the top half of the dial face, the atom will have a spin up, or “+” property, and if the dial in the atom is pointing in the bottom half, it will have a spin down, or “-” property. We have created a very basic hidden variable theory. We will soon find out, however, that it’s all we really need to show its limitations compared to quantum theory.Thinking Outside the Quantum Box
With knowledge of the hidden variables, there is no need for any “spooky action,” as Einstein put it. The dial determines the spin of the atoms at separation. And any measurement of the spin simply determines where the dial was when they were separated. Simple, right? Not quite.The Quantum Story, Fig 21
Bell took it a step further and began to calculate probabilities. If the magnetic fields are aligned for both detectors, we can say the probability for the dial to be in the top half of the dial face for Atom A is 50%. Because they have to have opposite spins, we can say the probability of Atom B’s dial to be in the bottom half is also 50%. We denote this as P+- = 50%. As long as the magnetic fields are aligned (as in Figure 20), we can also say P-+ = 50%. This is obvious as the top and bottom halves of the dial face each take up 50% of the total area. But what happens to this value if we rotate the magnets of the Atom B detector relative to Atom A’s detector? When you do this, what is considered the top half of the dial face rotates as well, changing the areas of each dial face half in relation to the dial. Because the dial is fixed into position, it means that the value of P+- will decrease as the angle of rotation increases. It’s easy to visualize if you think of the dial faces overlapping each other.
Consider Atom B at 45 degrees in the figure on the right. Superimpose it onto Atom A. You will see the area that the downward pointing dial can exist in has decreased. The beige colored top face is overlapping the bottom face. Remember that the dial is fixed into position – it cannot change. Do the same for 90 degrees, and you will see the area of the bottom face has decreased by exactly half. As the area decreases, the probability P+- decreases, and the probably of measuring both spins as spin up or “+” increases. With 180 degrees of rotation, probability P+- is at 0%. You now have P++, and we measure both spins as spin up.A Simple Idea Gives Rise to the Bell Inequality
Quantum Theory gives the value of P+- as 1/2 cos2 (a/2) where a = the angle between the magnet axes. John Bell’s simple hidden variables theory agrees with quantum theory only at angles 0, 90 and 180 degrees, as seen in the graph below. However, considering how crude our theory is, the possibility should exist to make a more elaborate hidden variables experiment that would show that all angles would agree. Is it possible to do this?The Quantum Story, Fig 22
After 17 years, John Bell realized that the answer was no, it is not. There is simply no way for any local hidden variables theory to account for all the predictions of quantum mechanics. He would go on to use a character by the name of Dr. Bertlmann, who had an unusual dress sense to eloquently describe his findings. And this will be the subject of part 2 of this post on Bertlmann’s Socks when all will be revealed, at least as much as is possible when it comes to Quantum Mechanics.Sources:
The Quantum Story, by Jim Baggott. Chapter 31 ISBN-978-0199566846
Filed under: Hackaday Columns
One way to develop longer-lasting batteries is to alter the chemical makeup of battery packs, and a number of researchers are looking for ways to do that. But a group of researchers at Microsoft are working on a way to make existing batteries last longer by using software. Software-defined batteries use a system of multiple batteries of different […]
One of our avid readers, [Niklas Melton] loves RC planes. After getting into 3D printing, the next logical step was to start building is own planes… And now he’s done it!
He calls it the Air-Form 1 Micro RC plane, paying homage to the FormLabs resin printer he used. All of the parts except for the electronics were printed using a tough resin. It’s designed to take balsa wood wings into clips he designed into the parts. A 150mAh battery provides the power with a motor that exerts about 54g of thrust — not bad considering the entire thing only weighs 60g! Unfortunately he doesn’t have any video clips of it flying, though he assures us it does indeed fly — if you’re interested in building your own, he’s uploaded all the files to a page on Thingiverse.
As more advanced 3D printers come down in price, like the SLA technology, it becomes possible to design and 3D print even more complex parts. Some of the resins available have now some pretty amazing properties. One of our readers replaced a servo spline gear with one he printed — which works even better than the original!
Filed under: 3d Printer hacks, radio hacks
Microsoft has been making tablets and smartphones for a few years, but now the company has introduced its first laptop. The Surface Book is a 13.5 inch notebook with a touchscreen display, an Intel Skylake processor, NVIDIA GeForce graphics, and up to 12 hours of battery life. Prices start at $1499, and the Surface Book […]
Microsoft’s 4th-gen Surface Pro tablet has a 12.3 inch, 2736 x 1824 pixel display with 267 pixels per inch. It’s bigger than the 12 inch screen on the Surface Pro 3, but the tablet is the same size since it has thinner bezels. Speaking of thinner, the new tablet is actually thinner and lighter than […]
Take a Raspberry Pi-sized mini computer, add Gigabit Ethernet, 802.11n WiFi, Bluetooth 4.0, and an FPGA with a whole bunch of I/O options, and what’ve you got? Apparently a Snickerdoodle. It’s a new single-board computer from hardware startup krtkl. The developers are hoping to raise funds for the project through crowdfunding site Crowd Supply. You […]
Snickerdoodle is a $55 mini PC for DIY robotics (and more) is a post from: Liliputing
Microsoft has officially introduced its new flagship-class smartphones. The Lumia 950 is a 5.2 inch smartphone with a Qualcomm Snapdragon 808 hexa-core processor, while the Lumia 950 XL has a 5.7 inch screen and a Snapdragon 810 octa-core CPU. Both phones ship with Windows 10 software, support Microsoft’s Continuum for Phone software that lets you […]
Microsoft’s second-generation Microsoft Band is a wearable fitness tracker with a new curved display, a Gorilla Glass 3 scratch-resistant screen, and a more flexible design, making it more comfortable to wear. It also has all the features of the original Microsoft Band, plus a barometer for real-time height detection. The new Microsoft Band costs $249, […]