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Hackaday Prize Entry: Boots And Cats And Boots And Cats

ศุกร์, 09/09/2016 - 12:00

Electronic drums are pricey, but the drums themselves are actually very easy to make. By simply putting a few piezos on some rubber mats, you can make a set of electronic drums. The real trick, and the expensive bit, is in the drum module. This module has inputs for the high hat, snare, toms, and bass drum to turn the repetitive thwaking of a stick on a rubber mat into drum sounds.

For his Hackaday Prize entry, [Jeremy] isn’t building a set of electronic drums. He’s building a drum module, complete with touchscreen interface and a GUI.

This isn’t [Jeremy]’s first go at building a drum module – his first implementation was RaspiDrums, an add-on for the Raspberry Pi that used accelerometers instead of piezos. The software works well enough with a USB sound card to serve as a set of real electronic snare.

Now [Jeremey] is moving up to a full kit, and the power of the Raspberry Pi means he can easily add a touch screen to his device. Right now the efforts are going into building a GUI using Gtkmm, and wrapping everything up into a front panel that makes sense and is easy to use. The drums themselves are a solved problem, making this Hackaday Prize entry a fantastic polish on an already great project.

The HackadayPrize2016 is Sponsored by:
Filed under: Raspberry Pi, The Hackaday Prize

Cityscape Infinity Table

ศุกร์, 09/09/2016 - 09:00

Redditor [ squishy0eye] lacked a coffee table and wanted an infinity mirror. So, in a keen combination of the two, she built an infinity mirror table the resembles a nighttime cityscape.

Skimming over many of table’s build details, [squishy0eye] paused to inform the reader that an MDF base was used underneath the mirrors, with a hole drilled for the future power cable. For the top pane, she overlaid privacy screen mirror film onto tempered glass, turning it into a one-way mirror. The bottom pane is acrylic plastic due to the need to drill holes to hide the cables for each ‘building’ — the same mirror film was applied here as well. Wood was cut into rectangles for the building shapes and super glued around the holes and in the corresponding spots underneath to prevent any bowing in the acrylic. A small gap was left in each ‘building’ to run the 5050 non-waterproof LED strips around and back into the hole for power.

After installing the bottom mirror, [squishy0eye] added some black paper on top of the buildings to hide the wires and LEDs as well as adding wood supports around the edge to create the slight gap between the mirrors necessary for the effect.

A quick LED test, and the top pane of glass was fit into place, creating an effect well worth the approximate $150 price tag.

Want some more LED action to compliment such a cool table? How about a TV made of LED strips that you can roll up and take with you.


Filed under: led hacks, misc hacks

31415926 (That’s roughly Π times 10 million Raspberries)

ศุกร์, 09/09/2016 - 06:01

The Raspberry Pi Foundation founder Eben Upton has announced that their ten millionth eponymous single-board computer has been sold since their launch back in February 2012. It’s an impressive achievement, especially so since their original sales expectations were for a modest ten thousand. For those of us who watched the RS and Farnell websites crumble under the strain of so many would-be purchasers on that leap day morning four and a half years ago their rapidly exceeding that forecast came as no surprise, but still, it’s worth a moment’s consideration. They passed the Sinclair ZX Spectrum’s British record of 5m computers sold back in February 2015, leaving behind the Pi’s BBC Micro spiritual ancestor on 1.5m sold long before that.

Critics of the Pi will point out that its various versions have rarely been the most powerful small single board computer on the market, or even at times the cheapest. They will also point to the closed-source nature of the Broadcom binary blob that underpins Pi operating systems, and even the sometimes unpredictable nature of the Pi Foundation with respect to its community, product availability and launches. But given that the Pi Foundation’s focus is not on our side of the community but on using the boards as a tool to introduce young people to computing, it’s fair to say that they’ve done a pretty good job of ensuring that a youngster can now get their hands on a useful and easily programmable computer much more easily than at any time in the past.

Would we be in the same position of being able to buy a capable Linux computer for near-pocket-money prices had the Raspberry Pi not been released? Probably so, in fact certainly so. The hardware required to deliver these products has inevitably fallen into a more affordable price bracket, and we would certainly have plenty of boards at our fingertips. They would probably have Allwinner or maybe Mediatek processors rather than the Pi’s Broadcom part, but they would be very likely to deliver equivalent performance at a similar cost. Where the Raspberry Pi’s continued success has come from then has not necessarily been from its hardware but from its community and software. The reliability and ease of use delivered by the Raspbian Linux distribution that Just Works for the parent putting a Pi in front of their child, and the wealth of expert information on the Raspberry Pi forums to get them through any Pi-related troubles are what has given the Pi these sales figures. The boards themselves are almost incidental, almost any hardware paired with that level of background information would likely have met with similar success. Comparing the Pi software experience with for example one of their most capable competitors, it’s obvious that the software is what makes the difference.

It’s likely that Raspberry Pi sales will continue to climb, and in years to come we’ll no doubt be reporting on fresh milestones on ever more powerful revisions of their product. But it’s also likely that their competition will up their software game and their position in the hearts and minds of single board computer users might be usurped by a better offering. If this increased competition in the single board computer market delivers better boards with more for the hardware developer community, then we’re all for it.


Filed under: news, Raspberry Pi

Reverse Engineering and Networking The A/C Remote Control

ศุกร์, 09/09/2016 - 03:00

IoT has become such an polarizing, overused term. But here it is in its essence: [zeroflow] had a thing (his airconditioner) and he needed to put it on the Internet.

For his contribution to this modern vernacular atrocity, he first had to build an IR debugging tool and reverse engineer the signals coming from the air conditioner’s remote. He wrote up a really good summary of the process, and worth reading. He loads up an IR library onto an Arduino and dumps the resulting 32 bits of information to his computer. In a process much like filling in the blanks on a word puzzle, he eventually determines which blocks of the data correspond to the remote’s different buttons.

Next he throws an array of IR LEDS and an ESP8266 onto a bit of protoboard. After writing some code, available on GitHub, he could set the temperature of his room from anywhere on the planet. We take it on faith that [zeroflow] has a compelling reason for doing so.

Bolstered by this success, he didn’t stop there. [Zeroflow] admits to having more than one thing on the Internet. Boom! Internet of things.


Filed under: home hacks

Top Ten Reasons Not To Buy A Fake MacBook Charger. Number Eight Will Shock You.

ศุกร์, 09/09/2016 - 01:31

Yesterday, Apple showed the world how courageous they are by abandoning their entire PC market. It’s not time for a eulogy quite yet, but needless to say, Apple hardware was great, and the charger was even better. It had Magsafe, and didn’t start fires. What more could you ask for?

When it comes to fake MacBook chargers, you can ask for a lot more. [Ken Shirriff] has torn apart a number of these chargers, and his investigations allowed for an obvious pun in this post. The fake ones will make sparks thanks to the cost-saving design, and shouldn’t be used by anyone.

A genuine Apple MacBook charger is a phenomenal piece of engineering, but the fake one is not. In fact, it’s almost the simplest possible AC to DC converter. The mains power comes in, it’s chopped up into pulses, and these pulses are turned into a high-current, low-voltage output in a flyback transformer. This output is converted into DC with a few diodes, filtered, and wired into a MagSafe adapter.

The genuine MacBook charger is much more complicated. Like the cheap copy, it’s a switching power supply, but has a few features that make it much better. The genuine charger does power factor correction, uses quality caps, has real isolation on the PCB, and uses a microcontroller that’s almost as powerful (and a direct architectural descendant) as the CPU in the original Macintosh. It’s this microcontroller that kept you safe that one time you decided to lick a Magsafe connector not allowing the full 20 Volts to go through until the connector has connected. Until then, the Magsafe connector only outputs 0.6 Volts. The fake charger doesn’t do this, and when you poke the connector with a paper clip, sparks fly.

This isn’t [Ken]’s first teardown of genuine and not Apple products. He’s done iPad chargers, iPhone chargers, and other small, square, white switching power supplies. The takeaway from these teardowns is that cheap chargers are a false economy, and you probably should pony up the cash for the real version.


Filed under: macs hacks, teardown

Review: The RC2014 Z80 Computer

ศุกร์, 09/09/2016 - 00:00

As hackers and makers we are surrounded by accessible computing in an astonishing diversity. From tiny microcontrollers to multi-processor powerhouses, they have become the universal tool of our art. If you consider their architecture though you come to a surprising realisation. It is rare these days to interface directly to a microprocessor bus. Microcontrollers and systems-on-chip have all the functions that were once separate peripherals integrated into their packages, and though larger machines such as your laptop or server have their processor bus exposed you will never touch them as they head into your motherboard’s chipset.

A few decades ago this was definitely not the case. A typical 8-bit microprocessor of the 1970s had an 8-bit data bus, a 16-bit address bus, and a couple of request lines to indicate whether it wanted to talk to memory or an I/O port. Every peripheral you connected to it had to have some logic to decode its address and select it when you wanted to use it, and all shared the processor’s bus. This was how those of us whose first computers were the 8-bit machines of the late 1970s and early 1980s learned the craft of computer hardware, and in a world of Arduino and Raspberry Pi this now seems a lost art.

The subject of today’s review then provides a rare opportunity for the curious hardware hacker to get to grips with a traditional microprocessor bus. The RC2014 is a modular 8-bit computer in which daughter cards containing RAM, ROM, serial interface, clock, and Z80 processor are ranged on a backplane board, allowing complete understanding of and access to the workings of each part of the system. It comes with a ROM BASIC, and interfaces to a host computer through a serial port. There is also an ever-expanding range of further peripheral cards, including ones for digital I/O, LED matrixes, blinkenlights, a Raspberry Pi Zero for use as a VDU, and a small keyboard.

The Build The RC2014 components as supplied.

Opening the packaging, the components and boards are neatly packed in plastic bags. There was no printed documentation with our kit, instead all documentation can be found on the project web site. The components are all easily identifiable, with through-hole passive components, sockets for the ICs, and large dual-in-line chips with clear markings. The modular nature of the kit means that each of the daughter cards has relatively few components, meaning that it splits the work into conveniently-sized units that are easy to build.

The exception to this convenience comes with the backplane, upon which are placed a series of long single-in-line sockets. It’s easy enough to solder 0.1″ pitch devices like these, but mildly tedious given the number of pins to be soldered. The outer two sockets have their data and address lines isolated by a set of jumpers which aren’t supplied, you will need to find and strip some hook-up wire to make these connections.

Our RC2014, half-built.

Part of the daughter board assembly is the attachment of a row of right-angle pins to mate with the backplane sockets. At this point during the assembly or our review system a flaw became obvious in the build. Different RC2014 daughter boards face in different directions, and by mistake we put the pins on the wrong side of a couple of the boards. It’s not an insurmountable problem but it slightly limits the order in which our modules can be placed. We’d suggest a very careful study of the online manual and photographs for each board, and not to be lulled into a false sense of security by the project’s relative ease of construction.

When all your daughter boards are ready it is a simple procedure to place them on the backplane. Pin 1 is clearly indicated on each board and can easily be aligned with the corresponding socket position. The only non-full-length board in the set is the clock oscillator, this is easily aligned not with pin 1 but with the GND pin marked on the backplane.

Our completed RC2014.

The build of our system was marred by the temperature controller on the soldering iron failing and the bit reaching a red-hot temperature. At the time this led to a Hackaday article on Weller tip availability, but for our RC2014 build it meant that on completion our system did not work. It exhibited a strange almost-functionality in which text sent from the RC2014 to the host computer could be read, but that sent from host to RC2014  was garbage.

With a lot of fault-finding with an oscilloscope, support from the kit’s designer, and continuity testing of connections failing to find an answer the kit languished until August’s EMF Camp, at which point it was possible to meet him face-to-face to get to the bottom of the problem once and for all. After an hour’s heroic customer support sitting amid the barbecue fumes of a festival hackspace village we finally traced the problem to an intermittent fault in one of the sockets. The extra-high soldering temperature had weakened a contact spring leaving it as a high enough resistance to cause problems but not enough to be detected as an open circuit. A quick replacement delivered instant results, and we had a working RC2014.

Up and Running

The build completed and a description of the hardware behind us, how about the software? Using the RC2014 could not be simpler, given an FTDI serial to USB lead you simply plug it into your host computer, configure the serial settings of your terminal software, press the reset button and away you go. The RC2014 is not an energy-hungry device, so happily takes its power via the FTDI from a USB slot.

Proof of a Hackaday writer having learned something at school.

The ROM BASIC comes courtesy of [Grant Searle], and is derived from one used in the Nascom computer kits of the late 1970s. It has a full implementation of a typical BASIC of the era, along with some custom keywords for conversion to binary and hex values. On start-up it gives you the option of  using the existing memory contents if it has been reset, followed by that of specifying a custom memory limit. Those choices over, and you find yourself in a BASIC interpreter; ready to dredge up those half-forgotten tricks gleaned from hours of typing in listings as a teenager.

A BASIC-generated Mandelbrot fractal shows off the RC2014’s graphical capabilities (rc2014.co.uk).

Happily many contemporary BASIC programs written for similar computers can be ported to the RC2014, and there is a GitHub repository with a lot of the hardware and ROM info as well as some BASIC examples. Loading code into the RC2014 without tediously typing can be done if your terminal supports sending text files to the serial port.

In a world in which we expect instantaneous computing it comes as something of a shock to run some software on the RC2014 and realise that it can take quite a while to complete. A BASIC interpreter on a few-MHz 8-bit microprocessor is hardly fast by today’s standards. But buyers of the RC2014 are after the 8-bit experience rather than the computing power it offers, so in that sense it offers an authentic peek into the past. Users of machines like this decades ago would have considered them to be startlingly quick, and minutes for a complex calculation would have seemed inconsequential compared to the hours required to do the same task by hand.

Do you Need One?

The RC2014 is probably the best way to get to grips with typical 8-bit microcomputer hardware of the era around 1980 that is available to the enthusiast some 35 years later. The modular design and clearly labelled bus probably make it more suitable for the experimenter than the single board designs of the day, when fault-finding the review board it was extremely easy to identify and trace signals with an oscilloscope. We certainly came away from this build knowing the machine at a much lower level than we would have with something more integrated.

If there is a gripe though with the RC2014 though it lies in its lack of physical documentation. Our experience with the faulty soldering iron was sheer bad luck, but we might have avoided the other minor wrong turnings we made had the information been more easily digested. This is however a minor issue as everything is there online if you are prepared to take it in and the support we received was of a very high quality, we would simply recommend to a would-be RC2014 builder that they take the time to really familiarise themselves with all the available information.

The RC2014 has full hardware information available on its website, and can be bought as a kit and with its ever-expanding range of peripheral boards through Tindie. If you have an interest in retro 8-bit microcomputer architectures then we can heartily recommend you take a look at it.


Filed under: classic hacks, computer hacks, Hackaday Columns

Nexmon Turns Nexus 5 (and RPi3!) Into WiFi Toolkit

พฤ, 09/08/2016 - 22:31

Back in the day, when wardriving was still useful (read: before WPA2 was widespread), we used to wander around with a Zaurus in our pocket running Kismet. Today, every cellphone has WiFi and a significantly more powerful processor inside. But alas, the firmware is locked down.

Enter the NexMon project. If you’ve got a Nexus 5 phone with the Broadcom BCM4339 WiFi chipset, you’ve now got a monitor-mode, packet-injecting workhorse in your pocket, and it looks a lot less creepy than that old Zaurus. But more to the point, NexMon is open. If you’d like to get inside what it took to reverse-engineer a hole into the phone’s WiFi, or make your own patches, here’s a great starting place.

But wait, there’s more! The recently released Raspberry Pi 3 has a similar Broadcom WiFi chipset, and has been given the same treatment, turning your RPi 3 into a wireless-sniffing powerhouse. How many Raspberry Pi “hacks” actually hack the Raspberry Pi? Well, here’s one.

We first learned of this project from a talk given at the MetaRhein-Main Chaos Days conference which took place last weekend. The NexMon talk (in German, but with slides in English) is just one of the many talks, all of which are available online.

The NexMon project is a standout, however. Not only do they reverse the WiFi firmware in the Nexus 5, but they show you how, and then apply the same methods to the RPi3. Kudos times three to [Matthias Schulz], [Daniel Wegemer], and [Matthias Hollick]!


Filed under: Cellphone Hacks, Raspberry Pi

Megasquirting My 1983 Datsun Z

พฤ, 09/08/2016 - 21:00
When Dinosaurs Drove to Work

Back in the mid 1980’s I worked at a company called Commodore Business Machines, a company that made home computers where our annual Superbowl was the Consumer Electronics Show in Las Vegas the first week in January.

Some time in November a Datsun Z would get parked in the front lot and then not move until whatever snow mounds that got plowed over it melted sometime in early spring. Ultimately I would have it towed leaving behind a sad little pile of rust and nuts and bolts. With a bonus check in hand for finishing the newest computer on time I would go buy another used Z and repeat the cycle.

Climate Change and Rust

These days the old Datsun Z’s; 240Z, 260Z, 280Z, 280ZX, are somewhat rare, probably because they were real rust buckets even when new. After having sacrificed a few myself in search of the next home computer I set out to rescue one for old times’ sake. I really did love the car so I made it my project to restore one. Now I have a total of three Z carcasses, an engine, and a transmission all sitting out back and an almost finished Z in the garage.

Since I had torn the engine down to its bare components I took the opportunity to make some changes: increased the size of the turbocharger, increased bore and stroke of the cylinder/piston, improved the fuel distribution, and improved the flow of air with things like porting the heads and an inter-cooler.

The Need For a New ECU

All of this means that I needed to modify the way the engine mixed fuel with air to support combustion, More air means that more fuel is needed in the same amount of time. Step one was bigger fuel injectors (and bigger fuel pump, regulator, filters, sump, plumbing, etc.) and this is why I needed a programmable Engine Control Unit (ECU).

From a diverse list of alternatives I chose to use a Megasquirt, a design that has heavy DIY roots. In my case I assembled the ECU myself a while back (this particular kit is from 2005). It now controls most of the vital functions in my car short of selecting what music I want to jam to.

Air Through the Engine

Seen here is a block diagram of the major components that control the function of the engine and as I say in the video, it’s all about the trip the air takes through the engine. Stepping on the throttle doesn’t directly add fuel as you might think, it really opens up a gate that allows more air into the combustion chambers which the ECU then compensates for by adding the appropriate amount of fuel.

The decision on how much fuel to add is based on not only how much air, but the temperature and a sensor in the exhaust that senses how completely the fuel is being burned. Other functions such as turning on the fuel pump and controlling the idle are examples of other functions the ECU can do. In my case I am not using the new ECU to control the spark that ignites the fuel; I have left control up to the stock ECU.

How to Measure the Airflow

My original Z engine measured the air flow with an inline Volume Air Flow (VAF) sensor that actually (and unfortunately) obstructs the flow of air in the process. This works by measuring the drag force of the air moving on a spring loaded vane. We call this arcane thing “the flapper” due to the way the vane flaps open and closed while operating. As this method measures the volume, the temperature of the air is as needed to determine the mass of the air.

An alternative way of measure the flow of air is the Mass Airflow (MAF) sometimes called a hot wire sensor. The simplest description is that it measures the cooling of a heated piece of wire by measuring its change of resistance or the change of current that is required to maintain it at a set temperature. The flow of air across the wire removes the heat (think thermodynamics) and it tends to rule out the effects of temperatures as it more directly measures mass not volume.

How the Megasquirt Measures Air

The Megasquirt does something different from what I described above. It uses a barometric sensor and measures the air pressure in the manifold, the space where fuel and air is mixed just prior to being sucked into the cylinders.

Combining this with other inputs such as the engine speed and O2 sensor is how the Megasquirt calculates how much fuel should be injected. But it gets even better. In addition to this improved method of monitoring combustion, I am in control of the calculations the ECU is making based on these measurements. This gives me a remarkable amount of control over pretty much everything the engine is doing.

The Tuner Studio Software

The software used to configure the Megasquirt is the Tuner Studio MS by EFI Analytics. I use the paid version which has additional features such as advanced tuning based on actual driving logging and performance.

There are a slew of basic configuration parameters that need to be loaded, basically the specifics about the engine including the number of cylinders , the fuel injector flow rates and even the type of fuel being used. Ultimately we end up with a Volumetric Efficiency (VE) map that is very similar to standard Fuel/Air maps in that we program how much fuel should be injected at different speeds and loads.

Click to view slideshow.

Additional variables such as when to enrich or modify the fuel amount under various conditions such as engine priming , wide open throttle (aka “flooring it”), and a warm-up period. My engine injects almost twice the amount of fuel when the engine is dead cold.

Teaching an ECU

With the Tuner Studio software plugged in and running it can accumulate live results from the way the engine performs under real life conditions and creates a table of suggested modifications to the VE map, which can then be applied. This means that the final performance is optimized beyond simple calculated values, in essence it should drive better every time until all of the parameters have been balanced through the tuning process.

Dash Bling

Finally the software can be run on a laptop of built in car computer using some of the designer dashboards included or the user can design their own dashboard with a wide range of gauges available including calculated values such as fuel economy.

Click to view slideshow.

I note that its now also possible to use an Android device for a remote dash cluster and I have to admit that the thought of one of my old mini-tablets on the dash in HUD mode kind of sounds cool.

The Kit

I built my ECU from a kit with the exception of the processor upgrade plugin was pre-assembled (all SMT). Its based on the MC9S12C64, a 16 bit processor running at 24 MHz with 4kB or RAM and 128 kB of flash, and has a few useful addons such as PWM controller and CAN interface.

Testing

Anytime you work on a system you’ll save yourself a lot of time with proper testing. In this case, removing the biggest variable — the car — is paramount. I have two different test units that plug into the “Big Ass Connector” of the ECU.

Shown here is my Megasquirt with one of the stimulators (the green PCB) available for configuring and troubleshooting. This was so much more useful than I thought it would be.

Disclaimer

All of the stuff I talked here is for off-road usage; it is unlawful to modify anything to do with federally mandated emissions control.

Resources
Filed under: Engine Hacks, Featured

Safely Remove Drill Chuck; Receive Motor, Gearbox, and Clutch

พฤ, 09/08/2016 - 18:01

There’s a treasure trove of usefulness inside of an electric drill. [Steven Dufresne], Hackaday writer and the mad scientist behind Rimstar.org, kindly documented how to safely and reliably remove the chuck from a drill motor. You may think this is easy, but once in a while you’ll come across a drill determined to hold onto all its bits. We certainly were entertained by the lengths [Steven] went to in the video below to get a Black and Decker to give up its chuck.

An understanding of how the chuck and gearbox are connected, combined with the right tools and a bit of force, gets you a motor, gears and gearbox, and a clutch. There’s not much left in the drill after that, and you can put some or all of those components to new use — like using them for the drive system of a BB-8 Droid.

Many projects (like this walking scooter) make use of cordless drills as motor sources. Being able to skip the chuck in order to interface directly to the shaft is useful for those projects where the drill is at least a semi-permanent part of the build. Ask your friends, neighbors, and at work. Cheap cordless drills and screw guns have been around for a long time. It’s usually the batteries that go and many people have the drills lying around and will be happy to part with them knowing you’re going to do something awesome with them.


Filed under: tool hacks

Ducklings Raised by Remote

พฤ, 09/08/2016 - 15:01

We’re not sure that it’s absolutely necessary to raise ducks using a remote-control animatronic duck decoy, but people have stranger hobbies.

This YouTube video (embedded below) from [Imaginative Guy] chronicles an impressive feat of RC animatronics, sparing no effort to make the RC duck “parents” realistic. There’s a ton of detail in the videos, from the machining of small necessary bits to the liberal application of hot glue where necessary.

We especially like the duck’s vocal-tract simulation: a speaker glued to the neck of a soda bottle makes (to our human ears) a very accurate duck sound. Cutting up RC helicopter blades to make a rudder is a pretty nice hack as well. There’s a lot to learn here. You know, for when you need to make a robot duck.

Naturally, this is not the first time that anyone’s strapped a remote-controlled submarine on a duck decoy. But it’s definitely the most refined that we’ve seen yet.


Filed under: misc hacks

Hackaday Prize Entry: An Electric Bike And A Dashboard

พฤ, 09/08/2016 - 12:00

Over the last few years, powerful brushless motors have become very cheap, batteries have become very powerful, and the world of quadcopters has brought us very capable electronic speed controls. Sounds like the perfect storm for a bunch of electric bike hacks, right? That’s what [bosko] is doing for his Hackaday Prize Entry. He’s building an e-bike with a big motor and an electronic dashboard, because a simple throttle switch would never do.

There are two parts to [bosko]’s bike, with the front brain box consisting of GPS, an OLED display, analog throttle, and a few wireless modules to connect to the other half of the system under the seat.

The drive section of this e-bike is as simple as it gets. It’s just a big brushless outrunner motor suspended directly above the rear tire, without any other connection. [bosko] has gone with the simplest power transmission system here, and is slightly wearing out the rear tire in the process. It works, though, and a few of the commentors over on Hackaday.io say it reminds them of the French Solex bike. We’re thinking this bike is more of what a riquimbili would be if Hobby King had a Cuban warehouse, but it seems to work well for [bosko] and is a great entry to the Hackaday Prize.

The HackadayPrize2016 is Sponsored by:
Filed under: The Hackaday Prize

Soft Robot With Microfluidic Logic Circuit

พฤ, 09/08/2016 - 09:00

Perhaps our future overlords won’t be made up of electrical circuits after all but will instead be soft-bodied like ourselves. However, their design will have its origins in electrical analogues, as with the Octobot.

The Octobot is the brainchild a team of Harvard University researchers who recently published an article about it in Nature. Its body is modeled on the octopus and is composed of all soft body parts that were made using a combination of 3D printing, molding and soft lithography. Two sets of arms on either side of the Octobot move, taking turns under the control of a soft oscillator circuit. You can see it in action in the video below.

Octobot mechanical and electrical analogue circuits (credit: Michael Wehner at al./Nature)

As shown in the diagram, the fuel is a liquid hydrogen peroxide (H2O2) which the oscillator gets from one of two fuel reservoirs and feeds into one of two reaction chambers. In the oscillator, pinch valves act like JFETs. When fuel from one reservoir is flowing into one reaction chamber, one of the pinch valves pinches off the flow of fuel to the other reaction chamber. It’s not clear how but somehow or other that fuel flow is then pinched off by another pinch valve as fuel then flows from the other reservoir to the other reaction chamber.

The reaction chamber contains a small amount of platinum as a catalyst which reacts with the hydrogen peroxide to release a much larger volume of oxygen gas into actuators in the arms. Those actuators expand like balloons causing the arms to move. The reaction chambers are the analogues of amplifiers. Other analogues are check valves for diodes, vent orifices for resistors as well as other chambers which appear to be capacitors.

This is a proof of concept and as yet the Octobot doesn’t walk but the team hopes to make one that can crawl, swim and interact with its environment. When it does we look forward to it joining this other soft-bodied bot modeled after a stingray. It looks like our overlords might all come from the sea.

Here’s you can see the Octobot in action.

And here’s another video from Harvard demonstrating the chemical reaction between hydrogen peroxide and platinum that produces oxygen.


Filed under: robots hacks

Water-Cooled LED Light

พฤ, 09/08/2016 - 06:00

[Matt] wanted to drive a Yuji LED array. The LED requires 30 V and at 100 watts, it generates a lot of heat. He used a Corsair water cooling system made for a CPU cooler to carry away the heat. The parts list includes a microphone gooseneck, a boost converter, a buck converter (for the water cooler) and custom-made brackets (made from MDF). There’s also a lens and reflector that is made to go with the LED array.

This single LED probably doesn’t require water cooling. On the other hand, adding a fan would increase the bulk of the lighted part and the gooseneck along with the water cooling tubes looks pretty cool. This project is a good reminder that if you need to carry heat away from something with no fans, self-contained water cooling systems are fairly inexpensive now, thanks to the PC market.

We might have put a shorting jack in the LED power line to do the current measurement. In the video, he cuts the wire to monitor it for a first-time calibration. Another alternative would be to build a digital ammeter into the box.

The link in the parts list looks like it moved. The LED is the 400HS which is a 100-watt array and is available in both a warm white and daylight white version. There’s also a circular version and the cost is around $75 at the moment. If you want something much less expensive, there’s an eBay link to a similar device for about $7. However, the parts list notes that the color rendition is not as good as the Yuji unit (and in the video below, you can see the color difference in a photo at time 13:30).

This build is not inexpensive but is certainly simpler than previous water-cooled lamp projects we’ve seen. On the other hand, a custom system can let you make use of the hot water you produce.


Filed under: led hacks

Tracking Airplanes From An Autonomous Boat

พฤ, 09/08/2016 - 03:00

Airplane tracking systems like FlightRadar24 rely on people running radios that receive the ADS-B signal and forward the data on to them. That doesn’t work so well in the middle of the ocean, though: in spots like the mid-Atlantic, there are no islands to speak of.

So, the service is now experimenting with a new approach: putting an ADS-B radio onto an autonomous boat. The boat is a Wave Glider from Liquid Robotics, an autonomous boat that harvests the power of the waves to run propulsion, guidance, and its payload. In this case, that payload includes an ADS-B receiver and a satellite transmitter that uploads the plane data to the service, where it is added to their mix of data sources. The boat is planned to spend the next six to eight weeks cruising about 200 miles off the coast of Norway, listening to the broadcasts of planes flying overhead and relaying them back to HQ. They will then be plotted on the live map in blue.

If you’re interested in building your own plane-trackers, we’ve got you covered, at least on land.


Filed under: radio hacks

Amazing Meccano Pinball Machine Fully Functional Before Meeting Its Fate

พฤ, 09/08/2016 - 01:30

[Brian Leach] of the South East London Meccano Club has put an impressive amount of ingenuity into making his pinball machine almost entirely out of Meccano parts. He started in 2013 and we saw an earlier version of the table back in 2014, but it has finally been completed. It has all the trappings of proper pinball: score counter, score multiplier with timeout, standing targets, kickouts, pot bumpers, drop targets, and (of course) flippers and plunger.

The video (embedded below) is very well produced with excellent closeups of the different mechanisms as [Brian] gives a concise tour of the machine. Some elements are relatively straightforward, others required workarounds to get the right operation, but it’s all beautifully done. For example, look at the score counter below. Meccano electromagnets are too weak to drive the numbers directly, so a motor turns all numbers continuously with a friction drive and electromagnets are used to stop the rotation at specific points. Reset consists of letting the numbers spin freely to 9999 then doing a last little push for a clean rollover to zero.

Despite pinball machines being obsolete (in the sense that no new machines get made apparently new machines do still get made!), there is a thriving cottage industry in refurbishing them and people seem to be constantly reinventing them as well. We’ve seen highly complex pinball-inspired games, immersive versions of pinball, supersized builds, and even pinball simulators. Something about the way pinball combines electrical and mechanical elements into a physical game of skill seems to inspire people get creative.

[Brian] mentions in the video that it’s time to dismantle the machine. Presumably the Meccano Club will reuse the parts in other amazing builds. It’s sad to see it go, but one thing remains: the high scores will never be broken.

Thanks for the tip, [Tim]!


Filed under: classic hacks

3D Printering: XT-CF20 Carbon Fiber Filament Review

พฤ, 09/08/2016 - 00:00

ColorFabb’s XT-CF20 is one of the more exotic filaments for adventurous 3D printerers to get their hands on. This PETG based material features a 20% carbon fiber content, aspiring to be the material of choice for tough parts of high stiffness. It’s a fascinating material that’s certainly worth a closer look. Let’s check it out!

An Abrasive Fellow

The high amount of carbon fibers makes this material extremely abrasive, so I obtained a hardened steel nozzle for my E3Dv6 hotend to print it without harming my brass nozzles. It’s also worth mentioning that the filament is capable of cutting deep grooves into extruder idlers and other printer parts on its way through the printer.

The Composition

XT-CF20 features an Eastman Amphora PETG base resin, which itself is already a tough material and lies about half way between PLA and ABS in terms of temperature resistance. Yet, PETG filaments are fairly undemanding to the printer hardware: No high nozzle or bed temperatures, no heated build chambers and also no exotic build plate materials are required. The XT-CF20 combines this resin with 20% carbon fibers. These fibers come as a finely milled filler rather than in the shape of long, reinforcing strands, so they surely don’t bestow super powers on printed parts. However, the XT-CF20 features a significantly increased shape fidelity, stiffness, and temperature resistance compared to the unfilled members of the XT family.

Print Quality

To get an encompassing idea of the material’s surface-finish, overhang tolerance, and bridging capabilities, I printed below Benchy, which resulted in a highly uniform texture and color with a nice matte finish. The bridges and overhangs at the cabin windows turned out great, and all details came out nicely. Despite all countermeasures, it has a tendency to ooze and create little blobs and artifacts here and there, which can be an obstacle to printing something that has to look perfect.

Conductivity

Probably by accident, the material safety data sheet describes this material as conductive, but nope, it’s merely antistatic. Despite the high carbon fiber content, the XT-CF20 features a surface resistivity of 109 Ω/sq (as stated in the technical datasheet) and is nothing you’d want to print your circuits with.

Warping

PETG filaments generally show a very low tendency to deform during printing, and with the high fiber content of the XT-CF20, the issue of warping goes down to virtually zero. Part of my tests were several massive 100 x 20 x 10 mm bars with 100 % infill, which I printed on a glue-stick-coated glass plate. It stuck to the plate perfectly straight during the 4 hour print with not a single corner lifted. That’s something I cannot even reproduce with PLA. In terms of shape fidelity, this material really deserves 5 out of 5 perfectly straight bananas.

Perfectly straight, chunky bars with 100% infill.

Build Plate Material And Adhesion

In my tests, the filament adhered to plain borosilicate glass briefly. Small objects could be printed directly to the glass surface, but taller objects were prone to just popping off during the print. With a thin layer of glue stick on the glass, I was able to print the massive blocks shown above with perfect build plate adhesion.

I also tested the material on my PEI build plate. The build plate adhesion was certainly stronger than necessary for a material that does not warp at all, but all parts could be removed without damaging the PEI plate or the parts themselves. Glue-stick on glass is probably the better solution for printing XT-CF20.

Bed Temperature

ColorFabb recommends 80 °C for the print bed, which worked great. Going below 80 °C led to problems getting the first layer to stick to the glue-stick-coated glass plate, but caused no problems when printing on the PEI plate.

Printing Temperature

The XT-CF20’s specified processing temperature ranges from 240 to 260 °C. I tested it at temperatures from 230 °C to 310 °C, and well, 240 to 260 °C is really the sweet spot. At 230 °C, parts can still be printed well, but the results are weak and break easily. Parts printed at 240 °C are already quite strong, but still have a slight tendency to break at the interface between the layers. At 260 °C, cracks no longer occur in between layers, but throughout the part, which indicates perfect layer bonding. Below fracture test series shows the difference quite clearly, and if you were wondering, was conducted by meticulous professionals using a laboratory-grade set of hammer and chisel.

At about 290° C, the material starts to noticeably deteriorate until printing becomes virtually impossible at 310 °C. Eventually, the best looking results were produced at 240 °C and 25 mm/s printing speed, with little oozing, while parts printed at 260° C and 25 mm/s printing speed were extraordinarily tough and showed perfect layer bonding.

Oozing

Not all PETG based filaments are alike, but many tend to ooze. So does the XT-CF2, with droplets of molten material flowing out of the nozzle during travel moves. Over the course of a print, some of these oozed material droplets are also collected back by the printing nozzle, where they accumulate to a larger drop of liquid plastic, which sooner or later drops down to the print, creating blob-like artifacts and sometimes even massive obstacles for the print head to run into.

The issue can be mitigated by printing at lower temperatures and speeds. With a printing temperature between 240 and 260 °C, printing becomes practical at 25 mm/s, with little oozing and low material buildup on the nozzle. Other settings I found helpful in mitigating oozing are a slight underextrusion, as well as activating “retractions on layer change” and turning off  “only retract when crossing perimeters” in Slic3r. Keeping the retraction length short — 2 mm for the E3D hotend I am using — speeds up the retraction moves and prevents nozzle clogging.

Printing Speed

ColorFabb recommends a print speed (40 – 70 mm/s) for the XT-CF20, although, within printing temperatures of 240 to 260 °C, the maximum printing speed I could achieve without strongly affecting layer bonding was 25 mm/s for perimeters and infill and 10 mm/s for small features. As mentioned before, lower printing speeds also result in reduced oozing and fewer blob-artifacts.

These values deviate a lot from ColorFabb’s recommendation, so I still could be wrong in my findings. Nevertheless, in ColorFabb’s comment sections, complaints are piling up from users who are unable to “print anything” with XT-CF20 and the recommended settings. In contrast to that, Pau from Tilt Racing Drones in Sweden published a highly positive review showing the great results from his efforts to print drone frames from XT-CF20 at painstaking 15 mm/s and 260° C.

Resilience

Parts printed from XT-CF20 are extraordinarily stiff and can take a beating. The technical data sheet attests XT-CF20 this outstanding toughness, below table puts the values into a known context.

ColorFabb
XT-CF20 ColorFabb
XT ABS
(typical) PLA
(typical) Flexural Modulus
ISO 178 / ASTM D790
molded specimen  6.2 GPa  2.1 GPa  2.3 GPa  2.3 GPa Tensile Strength (max.)
ISO 527 / ASTM D638
molded specimen  76 MPa  50 MPa  35 – 55 MPa  60 MPa Elongation At Break
ISO 527 / ASTM D638
molded specimen  7.5 %  10 %  20 %  4 % Glass Transition Temp.  80° C
(176° F)  75 °C
(167° F)  <105 °C
(<221 °F)  60 °C
(140 °F) Overhangs

With the settings dialed in, I threw a plain overhang test object with overhang angles from 15° to 75° at the material. It was printed at 0.2 mm layer height with a 0.4 mm nozzle at 240° C with a nozzle fan to selectively cool the overhangs. The test ended in a messy catastrophe when it reached the 75°, which destroyed the test piece, so I redid the test with a maximum overhang angle of 60° for the below photograph.

Bridging

A positive effect of the PETG resin’s high melt strength is its excellent bridging ability. The XT-CF20 bridges even large gaps of 40 mm without specialized print settings, and even made it across the 80 mm bridge. Note that these bridges were printed with default settings, such as a bridge flow rate of 100%, with only a nozzle fan to selectively cool the bridges. These settings might be tuned further for an individual setup to obtain better results.

 Support Material

I found it necessary to configure Slic3r to 0.0 mm Z-contact-distance to get a reasonable adhesion between the support structures and the actual print when using XT-CF20 on my single extruder setup. Also, a higher extrusion width of 0.7 mm for the support structures was necessary to prevent Slic3r’s support material from degenerating, since it’s printed with a greater layer height. The support material could still be removed and breaks easily at the touching points. Given the resilience of the material, the support structures themselves were also quite rigid, which could be a problem when printing objects with a lot of support material all around them.

Hygroscopicity Generic mechanism for hydrolysis by FrozenMan CC BY-SA 4.0

A noteworthy property of the XT-CF20’s PETG base resin is its hygroscopicity. It absorbs water from ambient humidity, which then leads to a chemical reaction named hydrolysis once it’s printed — or otherwise heated above 160° C. The reaction causes the longer polymer chains in the material to decompose into shorter chains, which results in higher brittleness of the material. Wet PETG can be dried for a few hours at 65 °C, although preventing it from getting wet in the first place by storing the filament in a sealed bag with silica gel seems to be the way to go here.

Safety

XT-CF20 comes with a material safety data sheet that should be read. In particular, dust created when sanding or otherwise processing the material should not be inhaled and can also form an explosive mixture with air. The filament is not explicitly hazardous, but the MSDS clearly lacks accurate toxicological data. For good measure, I’d rather not use this material for objects that come in contact with humans on a regular basis or use a varnish to seal the printed parts.

Conclusion

XT-CF20 has its caveats. Oozing is still a problem, and the low printing speeds take the fun out of the large, tough parts that this material would theoretically enable you to print. Nevertheless, it’s an exceptional material, capable of a beautiful surface finish, while at the same time being extremely tough and able to replicate steep overhangs and wide bridges. Because it does not require high temperatures or special build plates, it can be printed on virtually any printer that can be equipped with a steel nozzle (or comes with a cheap supply of brass ones). And it does not warp a micron. There are many use-cases where a tough material of high stiffness saves the day, regardless of little deficiencies or long printing times. Be it DIY drone frames, GoPro fixtures or even functional, load-bearing parts for 3D printers and small CNC mills.

I hope you enjoyed diving into a rather exotic 3D printing filament with this very first filament review on Hackaday. Have our readers yet run into projects where they’d wished for a tougher material? Other filaments you’d like to see here? Let us know in the comments!


Filed under: 3d Printer hacks

Nintendo Wields DMCA Axe On Fan Games

พุธ, 09/07/2016 - 22:30

In a move that may sadden many but should surprise nobody, Nintendo of America has issued a DMCA takedown notice for 562 fan-created games created in homage to Nintendo originals and hosted on the popular Game Jolt site. Games affected include Mario, Zelda, and Pokémon based creations among others, and Game Jolt have responded, as they are required to, by locking the pages of the games in question. They state that they believe their users and developers should have the right to know what content has been removed from their site and why the action has been taken, so they have begun posting any notices they receive in their GitHub repository.

It is likely that this action won’t be appreciated within our community, however it’s important to note that while there are numerous examples of DMCA abuse this is not one of them. Nintendo are completely within their rights over the matter, if you use any of the copyrighted Nintendo properties outside the safe harbor of fair use then you will put yourself legitimately in their sights.

Something that is difficult to escape though is a feeling that DMCA takedowns on fan-created games are rather a low-hanging fruit. An easy way for corporate legal executives to be seen to be doing something by their bosses, though against a relatively defenseless target and without really tackling the problem.

To illustrate this, take a walk through a shopping mall, motorway service station, or street market almost anywhere in the world, and it’s very likely that you will pass significant numbers of counterfeit toys and games copying major franchises including those of Nintendo. A lot of these dollar store and vending machine specials are so hilariously awful that their fakeness must be obvious to even the most out-of-touch purchaser, but their ready availability speaks volumes. Unlike the fan-created games which are free, people are buying these toys in huge numbers with money that never reaches Nintendo, and also unlike the fan-created games there’s not a Nintendo lawyer in sight. Corporate end-of-year bonuses are delivered on the numbers of violations dealt with, and those come easiest by piling up the simple cases rather than chasing the difficult ones that are costing the company real sales.

We’ve covered many DMCA stories over the years, and some of them have been pretty shocking. Questions over its use in the Volkswagen emissions scandal, or keeping John Deere tractor servicing in the hands of dealers. Let’s hope that the EFF and Bunnie Huang’s efforts pay off and dismantle section 1201, one of the most nonsensical parts of the law.

Via Engadget. Dendy Junior unauthorised Nintendo Famicom clone image, By Nzeemin (Own work) [CC BY-SA 3.0], via Wikimedia Commons.
Filed under: news, nintendo hacks

The Quantum Eraser

พุธ, 09/07/2016 - 21:01

Richard Feynmann noted more than once that complementarity is the central mystery that lies at the heart of quantum theory. Complementarity rules the world of the very small… the quantum world, and surmises that particles and waves are indistinguishable from one other. That they are one and the same. That it is nonsensical to think of something, or even try to visualize that something as an individual “particle” or a “wave.” That the particle/wave/whatever-you-want-to-call-it is in this sort of superposition, where it is neither particle nor wave. It is only the act of trying to measure what it is that disengages the cloaking device and the particle or wave nature is revealed. Look for a particle, and you’ll find a particle. Look for a wave instead, and instead you’ll find a wave.

Complementarity arises from the limits placed on measuring things in the quantum world with classical measuring devices. It turns out that when you try to measure things that are really really really small, some issues come up… some fundamental issues.  For instance, you can’t really know exactly where a sub-atomic particle is located in space. You can only know where it is within a certain probability, and this probability is distributed through space in the form of a wave. Understanding uncertainty in measurement is key to avoiding the disbelief that hits you when thinking about complementarity.

This article is a continuation of the one linked above. I shall pick up where I left off, in that everyone agrees that measurement on the quantum scale presents some big problems. However, not everyone agrees what these problems mean. Some, such as Albert Einstein, say that just because something cannot be measured doesn’t mean it’s not there. Others, including most mainstream physicists, say the opposite — that if something cannot be measured, it for all practical purposes is not there. We shall continue on our journey by using modern technology to peer into the murky world of complementarity. But first, a quick review.

The Double Slit Experiment — Where It All Began

Firstly, there are purists out there that will disagree with my approach to explaining these concepts. I must plead with you that it is not my goal to submit this article to The Scientific Journal for review. My goal is simply to rip away the complexities that naturally follow this advanced topic, and present it in an easy-to-understand format that anyone can enjoy and learn from. But by all means feel free to expand on anything in the comments!

Complementarity was developed to help understand the results of laboratory experiments. Today, the idea of complementarity resides at the heart of what is known as the Copenhagen interpretation of quantum mechanics. There are other interpretations out there, but the Copenhagen model is the most widely accepted.

Source: Rollins.edu

The laboratory experiments I speak of revolve around the double slit experiment, which can differentiate between a particle and a wave. Imagine you’re at a gun range and you put up a large target. In between you and the target is erected a large steel wall with two narrow slits…maybe six inches wide and two feet apart. You fire a few hundred rounds with your machine gun, and then observe the pattern on the target. You will find an obvious pattern – two narrow lines where the bullets went through the slits.

Now let us take our large steel wall with the two slits and stick it in a lake, so that the slits are just above the surface. Behind the wall, we’ll place some type of detector that can detect waves. We toss a large rock into the lake and watch the resulting wave emanate from the point of impact and strike the wall. On the other side of the wall, two other waves appear from the slits. The slits will each act like a wave source. The waves from each source will interfere with each other and produce a distinct pattern on our detector wall. It’s known as an interference pattern, and consists of several lines of different intensities.

Source: maths.org

Now, you should see where we’re going with this. If we have an unknown substance, and we want to know if it is made of particles or waves, we can perform this experiment. Light, for instance, will produce an interference pattern. And that makes perfect sense – it’s an electromagnetic wave. One would think that sub-atomic particles would produce a pattern like our machine gun bullets did – two distinct lines. It turns out that this is not the case. They will produce an interference pattern as well. And that most certainly does not make sense.

Source: maths.org

But physicists are clever, and decided to try firing one particle at a time at the double slit. About one particle per hour. But it yields the same result — an interference pattern! The particle is acting like a wave, as if it went through both slits at the same time! That’s impossible! We must take a closer look. We will observe the single particle to see which slit it goes through. Turns out that when you do this, you will get the double line pattern like you expected. If we look at it, we will see a particle. If we don’t look at it, we will see a wave. And thus was born the concept of complementarity.

The idea that “observation determines reality” gets into a philosophical quagmire that I’m not touching with a 39 foot HF antenna. But we can probe deeper into this mystery with an experiment. What if we could observe the particle/wave/whatever AFTER it goes through the slit and BEFORE it hits the detector wall? This is precisely what the quantum eraser experiment does.

The Quantum Eraser

Like several concepts in quantum theory, originally thought experiments were developed to explore an idea or approach, but technology has advanced to the point where we can actually carry out some of them. The quantum eraser experiment is one such experiment, and was carried out at the University of Maryland in 1999.

The experiment starts with visible light photons traveling through a double slit. The exiting light immediately hits a prism which splits a single photon into an entangled pair.  A lens then directs one of the photons to detector D0. The other photon goes to another prism. What happens next depends on which slit the original photon came through. If it came from the top slit (path pictured in red), it will go to a half-silvered mirror BSb. If it came from the bottom slit (path pictured in blue), the prism will direct it to half-silvered mirror BSa. Note that “BS” stands for “Beam Splitter”: a half-silvered mirror will allow 50% of the photons to pass, and will reflect the other 50%.

Source: wikipedia.org

The BSb mirror will send 50% of the photons from the top slit to detector D4 and the other 50% to the mirror Mb. The photons from Mb head to another half-silvered mirror BSc. This mirror will send 50% of the photons to detectors D1 and D2 respectively.

A similar action occurs with photons coming through the bottom slit. They will hit BSa, which sends photons to detector D3 and mirror Ma. From Ma, they will go to mirror BSc, which takes half of the photons to D1 and the other half to D2.

In the end, photons from the top slit will go to detectors’ D1, D2 and D4. Note that no photons from the top slit can reach detector D3. Photons from the bottom slit will go to detectors’ D1, D2 and D3. No photons from the bottom slit can reach detector D4. Note that it is not possible to determine which slit the photons that hit D1 and D2 originated from. So this is what we have:

  • Top slit = D4
  • Bottom slit = D3
  • Unknowable = D1 and D2

Detector D0 lies on the shortest path, so a photon will strike it approximately 8 nanoseconds before its entangled partner reaches another detector. The Coincidence Counter allows us to assign a photon that strikes D0 to its entangled partner, which strikes D1 – D4.

So we put 12v on the Arduino Uno and let the photons loose. This is what we find — D3 and D4 (labeled “R0n” in the Wiki images) show a particle pattern. D1 and D2 show an interference pattern. And this makes sense. We cannot know which slit the photons detected at D1 and D2 came through. So they act as a wave. And we know which slit the photons detected at D3 and D4 came through, so they act like particles. But this is not the point of the experiment.

Note how the bands are opposite of each other in R01 and R02. This corresponds to the R01 and R02 waveforms in the top image. See the Wiki for more information on why this occurs.

The neat stuff is going on at detector D0. For every photon that hits D1 – D4, it has an entangled partner that hits D0 8ns earlier. Like the other detectors, D0 can resolve a particle or wave pattern. This is doing exactly what we wanted to do — we’re looking at the particle AFTER it goes through the slit (via D0), but BEFORE it hits the detector wall, which in this case is made of detectors’ D1 – D4.

What they found was that the photons that hit D0 always — as in 100% of them — correlated to their partner photons. And this, my fellow hackers, should be impossible. Why? Because:

  • The photons hit D0 8 nanoseconds before D1 – D4.
  • The photons have a 50/50 chance of hitting D1/D2 or D3/D4.

How then can the photon that hits D0 know if its entangled partner went to D1/D2 or D3/D4? We are forced to consider an impossible scenario:

  • The photons that end up at D1 and D2 must be sending information 8ns into the past to tell its entangled partner at D0 to become a wave.
  • The photons that end up at D3 and D4 must be sending information 8ns into the past to tell its entangled partner at D0 to become a particle.

This, my friends, is a simplified explanation of what the quantum eraser is all about. It “erases” the past, preventing us from ever knowing which slit the photon came through. Bohr was right: complementarity is real, impossible as it might seem. However, our problem lies not with what appears to be undeniable time travel. Our problem is that how we view the natural world is not compatible in the quantum realm. To ask if it is a wave or particle is nonsense. To ask if it’s even there is nonsense. There is no such thing as “there” in the quantum realm. Concepts like time and space, cause and effect …have different meanings there… meanings that we’re still not sure of to this very day.

Encourage your sons, daughters, nieces and nephews to take the helm and study quantum theory. Stir their curiosity… there are stories yet to be told, and discoveries that remain to be made. Many of which are surely greater than the greatest fiction, but whose fantastic implications are rooted in a very real reality — the next frontier of modern science.


Filed under: Engineering, Featured, slider

Raspberry Pi Walkie Talkie Mumbles To Friends

พุธ, 09/07/2016 - 18:01

His kids wanted walkie talkies, so [Daniel Chote] built one. The TalkiePi is a neat project built around a Raspberry Pi running Mumble, the open-source voice chat system that his kids can share with their siblings and friends.

It’s easy enough to choose the Raspberry Pi, and Mumble is pretty well known. But what’s the easiest way you can think of to add microphone and speakers to the RPi? We applaud [Daniel’s] choice to equip it with the guts of a USB speakerphone. Mumble lets you choose voice activation or keyboard input — in this case an added button makes it push-to-talk, as you would expect in a traditional walkie talkie.

He put all of this into a nicely designed 3D case with a few LEDs, so it is easy to tell that it is ready to transmit. [Daniel] isn’t quite finished yet, though: he’s now working on a new version that is portable, battery powered and uses a Raspberry Pi Zero for the ultimate walkie talkie. We can’t wait to see someone take this to the extreme and include a cellular-modem. But then again, anywhere you can get on WiFi this rig should work, it’s not relegated to a single LAN, and that already far outperforms walkie talkies of yore.


Filed under: Raspberry Pi, wireless hacks

Cheap Toy Airboat Gets a Cheap R/C Upgrade

พุธ, 09/07/2016 - 15:01

[Markus Gritsch] and his son had a fun Sunday putting together a little toy airboat from a kit. They fired it up and it occurred to [Markus] that it was pretty lame. It went forward and sometimes sideward when a stray current influenced its trajectory, but it had no will of its own.

The boat was extracted from water before it could wander off and find itself lost forever. [Markus] did a mental inventory of his hacker bench and decided this was a quickly rectified design shortcoming. He applied a cheap knock-off arduino, equally cheap nRF24L01+ chip of dubious parentage, and their equivalent hobby servo to the problem.

Some quick coding later, assisted by prior work from other RC enthusiasts, the little boat was significantly upgraded. Now the boat could be brought back to shore using any R/C controller that supported the, “Bayang,” protocol. He wouldn’t have to face the future in which he’d have to explain to his son that the boat, like treacherous helium balloons, was just gone. Video after the break.


Filed under: Arduino Hacks, toy hacks