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2015 THP: Judges and Sponsors

พุธ, 03/11/2015 - 06:01

And now it’s time to recognize a big part what makes the Hackaday Prize possible: our Judges and our Sponsors. First up are the Judges. We are fortunate again this year to be joined by top experts from around the world. We are going to briefly touch on each in this post, but you really should hit the Judge’s page for bios and links on everyone.

New Judges in 2015

We have seven judges new to the panel this year:

We love seeing a project pic used as an avatar and [Akiba] of freaklabs didn’t disappoint; we covered that project in 2013. [Pete Dokter], known well for According to Pete, joins us from Sparkfun. [Lenore Edman] and [Windell Oskay] are the force behind Evil Mad Scientist Labs. [Heather Knight] of Marilyn Monrobot is finishing her PhD in Robots at Carnegie Mellon. [Ben Krasnow] should need no introduction; formerly of Valve, currently of Google[x], and always of Applied Science. [Micah Scott] is artist/engineer/hacker and her Blu-Ray drive RE work is among our most favorite of 2014 hacks.

Returning Judges

Five of our friends from the 2014 Hackaday Prize are returning this year:

We have a hard time calling the founder of Adafruit anything other than [Ladyada] but you may know her as [Limor Fried]. The hardware design site The Ganssle Group is spearheaded by [Jack Ganssle]. You know [Dave Jones] from his electronics design and reverse engineering videos on EEVblog and also from the Amp Hour podcast. [Ian Lesnet] is a Hackaday alum, creator of Dangerous Prototypes, and expert regarding manufacturing in China. And finally, [Elecia White] is an extraordinary embedded engineer, founder of Logical Elegance, and the Embedded podcast.

Welcome back, and so happy to have the new Judges this year!

2015 Hackaday Prize Sponsors

The 2015 Hackaday Prize is presented by Supplyframe (parent company of Hackaday). This year we have added five giants of the hardware world as sponsors. We don’t recall having seen so many major players come together for a single initiative. We’re excited that they share our vision of supporting design initiatives. Please thank them by following their Hackaday.io pages: Atmel, Freescale Semiconductor, Microchip, Mouser Electronics, and Texas Instruments. Thank you sponsors!


Filed under: roundup, The Hackaday Prize

The Making Of The Hackaday Prize Video

พุธ, 03/11/2015 - 04:30

As you’re probably aware, there’s a video announcing the launch of The Hackaday Prize blocking the front page of Hackaday right now. This is by design, and surprisingly we haven’t gotten any complaints saying, ‘not a hack’ yet. I’m proud of you. Yes, all of you.

Making this video wasn’t easy. The initial plans for it were something along the lines of the new Star Wars trailer. Then we realized we could do something cooler. The idea still had Star Wars in it, but we were going for the classics, and not the prequels. As much as we love spending two hours watching a movie about trade disputes, we needed to go to Tatooine.

I just wanted to go to Toshi station

This meant building a prop. We decided on the moisture vaporators from Uncle Owen’s farm. It’s a simple enough structure to build at the Hackaspace in a weekend, and could be broken down relatively easily for transport to the shooting site. I’ve created a hackaday.io project for the actual build, but the basic idea is a few pieces of plywood, an iron pipe for the structural support, and some Coroplast and spray paint to make everything look like it’s been sitting underneath two suns for several decades.

Oh, I was the only person at the hackaspace that knew what greebles were. That’s not pertinent in any way, I’d just like to point that out.

The Suit

The vaporator is the star of the show, but we also rented a space suit. No one expected teflon-covered beta cloth when we were calling up costume rental places, but the suit can really only be described as a space-suit shaped piece of clothing. The inlet and outlet ports are resin, and the backpack is a block of foam. If anyone knows where we can get an Orlan spacesuit, or even a NASA IVA or Air Force high altitude suit, let us know.

Credits

[Matt Berggren] led the prop build and starred in the assembly footage. [Aleksandar Braic] and [Rich Hogben] rented a ridiculous amount of camera equipment. On set for the hijinks was [Aleksandar “Bilke” Bilanovic], [Brian Benchoff] (me), [Jasmine Bracket], [Sophi Kravitz], and [Mike Szczys].


Filed under: The Hackaday Prize

2015 THP Inspiration: Medical Hacks

พุธ, 03/11/2015 - 03:00

Last year’s Hackaday Prize focused on building something cool, useful, and open. This led to builds as impressive as quadcopters nicknamed the Decapitron, to devices as useful as an Everything Radio. It’s a big field, and if you want to build something that will win, you first need an idea.

This year we’re making that part of the process a little easier for you. We’re looking for builds that matter, be they devices that monitor pollution, feed entire populations, lay the groundwork for powering an entire city, or reduce the cost and increase access to medical care.

Medical builds are a tricky subject, but over the years we’ve seen a few that stand out. Some can be as simple as a pill dispenser that tells the Internet when you don’t take your meds. This type of build is actually pretty popular with several iterations, one that works with pill bottles.

Maybe a gadget you could find in a drug store isn’t your thing. That’s okay, instead you can turn your attention to advanced medical imaging, like 3D printing a brain tumor and preventing a misdiagnosis. We’ve seen 3D printed MRI and CT scans for a while now, and coming up with a system that automates the process would be a great entry for the Hackaday prize.

Of course with 3D printers, you have a bunch of prosthesis applications; from a nine-year-old who designed his own prosthetic arm, a printed prosthetic arm for a stranger, or something simpler like our own [Bil Herd]’s quest to rebuild a finger.

These are all simple builds, but ones that clearly meet the criteria of doing something meaningful. The sky is the limit, and if you want to improve the desktop CT scanner, learn CPR (correctly) from an automated assistant, or be brought back to life with your own design, that’s all well within the goals of this year’s Hackaday Prize.


Filed under: Medical hacks, The Hackaday Prize

2015 Hackaday Prize: Build Something that Matters

อังคาร, 03/10/2015 - 21:01

Last year we challenged you to build the next generation of connected devices. Six months later, the best teams and projects from around the world battled for the greatest prize of all: the respect of their peers and a trip to space. This year, we’re issuing a call to hackers, engineers, makers and startups from all over the world, to focus their creative efforts on nothing less than solving serious issues facing humanity.

Fix the World

We’ll all be facing a lot of problems in the next few decades, whether they’re from rising costs and consumption of oil, droughts, access to food, demographic shifts in populations, or increasing health care costs. These problems need to be dealt with, and there’s no better time than right now to start working on solutions.

What do we want from you? We want you to identify the greatest problems faced by humanity in the next few years and come up with a solution. This can be anything from better, lower-cost solar power components, inexpensive ultrasound machines, better ways to store drugs, more advanced ways of measuring farm production, or cheaper, more sustainable smartphones to bridge the digital divide. The world is full of problems, but if there’s one thing hackers have taught us, it’s that there are more than enough people willing to find solutions.

Prizes

If worldwide notoriety isn’t enough personal incentive, Hackaday is back with a huge slate of prizes for those devices that best exemplify solutions to problems that matter.

The Grand Prize is a trip to space on a carrier of your choice or $196,883 (a Monster Group number). Other top prizes include a 90-Watt laser cutter, a builder kit (pcb mill, 3d printer, cnc router, bench lathe), a tour of CERN in Geneva, and a tour of Shenzhen in China.

New this year is the Best Product award. Go the extra mile and show a production-ready device (in addition to supplying three beta test units for judging) and you can score $100,000! The entry is of course still eligible to compete for the Grand prize and other top prizes.

We’re able to pull this off once again thanks to the vision of Supplyframe who managed to unite giants of the electronics industry as sponsors of the 2015 Hackaday Prize. Atmel, Freescale, Microchip, Mouser, and Texas Instruments have all signed on in supporting this mission.

Individuals, Colleges, Hackerspaces, and Startups

If you just don’t want to go-it alone, get your team excited. After all, it was a team that won the Grand Prize last year. SatNOGS transformed the cash-option of $196,418 into a jumpstart for a foundation to carry the project forward. Get the boss on board by touting the notoriety your company will get from showing off their engineering prowess. Or help build your resume by herding your college buddies into some brainstorming session. And the Best Product prize is perfect for Startups who want to show off their builds.

Judges

Joining the Judging Panels this year are Akiba (Freaklabs), Pete Dokter (Sparkfun), Heather Knight (Marilyn MonRobot), Ben Krasnow (GoogleX & host of Applied Science on YouTube), Lenore Edman & Windell Oskay (Evil Mad Scientist Labs), and Micah Scott (Scanlime).

Our returning judges are Limor “Ladyada” Fried (Adafruit), Jack Ganssle (Ganssle Group, & The Embedded Muse), Dave Jones (EEVBlog), Ian Lesnet (Dangerous Prototypes), and Elecia White (Logical Elegance).

You can read all of the judge bios and find social media and webpage links for them on our Judges page. We are indebted to these industry experts for sharing their time and talent to make the Hackaday Prize possible.

Tell Everyone

We don’t ask often: please tell everyone you know about the 2015 Hackaday Prize! Social media share icons are just above the image at the top of this post. Submit this page or the prize page (http://hackaday.io/prize) to all your favorite sites. No hacker should get through this day without hearing about #HackadayPrize and we can’t reach total media saturation without your help. Thanks in advance!

GET STARTED NOW

Don’t wait, put up an idea right now and tag it with “2015HackadayPrize”. We’re sending out swag for early ideas that help get the ball rolling. And as you flesh out your plans you could score prizes to help build the prototype like PCBs, 3D prints, laser cutting, etc. Make it to the finals and you’ll be looking at the five top prizes we mentioned earlier. A simple idea can change the world.


Filed under: contests, Featured, slider, The Hackaday Prize

Open Source, 3D Printed Rocket Engines

อังคาร, 03/10/2015 - 18:00

A liquid-fuel rocket engine is just about the hardest thing anyone could ever build. There are considerations for thermodynamics, machining, electronics, material science, and software just to have something that won’t blow up on the test rig. The data to build a liquid engine isn’t easy to find, either: a lot of helpful info is classified or locked up in one of [Elon]’s file cabinets.

[Graham] over at Fubar Labs in New Jersey is working to change this. He’s developing an open source, 3D printed, liquid fuel rocket engine. Right now, it’s not going to fly, but that’s not the point: the first step towards developing a successful rocket is to develop a successful engine, and [Graham] is hard at work making this a reality.

This engine, powered by gaseous oxygen and ethanol, is designed for 3D printing. It’s actually a great use of the technology; SpaceX and NASA have produced 3D printed engine parts using DMLS printers, but [Graham] is using the much cheaper (and available at Shapeways) metal SLS printers to produce his engine. Rocket engines are extremely hard to manufacture with traditional methods, making 3D printing the perfect process for building a rocket engine.

So far, [Graham] has printed the engine, injector, and igniter, all for the purpose of shoving oxygen and ethanol into the combustion chamber, lighting it, and marveling at the Mach cones. You can see a video of that below, but there’s also a few incredible resources on GitHub, the Fubar Labs wiki, and a bunch of pictures and test results here.


Filed under: 3d Printer hacks

Fail Of The Week : Measuring DC Current Has To Be Easy, Right?

อังคาร, 03/10/2015 - 15:00

[DainBramage] needed a DC ammeter to check how long his amateur radio station would be able to stay powered on battery backup power. The one’s he already had on hand were a Clamp Meter, which could only measure AC, and another one that measured just a few milliamps. Since he didn’t have one which could measure up to 25A, he decided to build his own DIY DC Ammeter with parts scavenged from his parts bin. Measuring DC current is not too difficult. Pass the current to be measured through a precision resistor, and measure the voltage drop across it using a sensitive voltmeter.

I = V/R

So far, so good. If it’s late at night and you’ve had a lot of coffee, busy building your DC ammeter, things could head south soon. [DainBramage]’s first step was to build a suitable Shunt. He had a lot of old, 1Ω, 10W resistors lying around. He made a series-parallel combination using nine of them to create a hefty 1Ω, 90W shunt (well, 0.999999999 Ohms if you want to be picky). This gave him a nice 1 Volt per Amp ratio, making it easy to do his measurements.

Next step was to hook up the shunt to a suitable voltmeter. Luckily, he had a Micronta voltmeter lying around, ripped out from a Radio Shack product. Since he didn’t have the voltmeter data, he hooked up a 10k resistor across the meter inputs, and slowly increased the voltage applied to the meter. At 260mV, the needle touched full-scale and the voltage across the inputs of the voltmeter was 33mV. [DainBramage] then describes the math he used to calculate the resistors he would need to have a 10A and a 25A measurement range. He misses his chance to catch the fail. His project log then describes some of the boring details of putting all this together inside a case and wrapping it all up.

A while later, his updates crop up. First thing he probably realized was that he needed more accurate readings, so he added connectors to allow attaching a more accurate voltmeter instead of the analog Micronta. At this point, he still didn’t catch the fail although it’s staring him straight in the face.

His head scratching moment comes when he tries to connect his home made ammeter in series with the 12V DC power supply to his amateur radio station. Every time he tries to transmit (which is when the Radio is drawing some current), the Radio shuts off.  If you still haven’t spotted the fail, try figuring out how much voltage gets dropped across the 1Ω shunt resistor when the current is 1A and when it is 5A or more.


Filed under: Fail of the Week, Hackaday Columns

Dirt Cheap Plywood Bike Holder

อังคาร, 03/10/2015 - 12:00

Commuting to work on a bicycle saves tons of dough, but sometimes storing your bike isn’t that easy. [Lewis] has been playing around with a few prototype bike stands and seems to have found the ticket, and it’s way cheaper –maybe even free, if you have the supplies. All you need is a single strip of plywood, and some wood screws, or wood glue! Well, that and a woodworking clamp.

The stand is designed to clamp onto 4×4 posts, or even a 2×4 stud. It’s great for storing bikes along your fence! It’s built purposefully snug, which allows you to add a small clamping force to make for a very rigid stand, suitable for even old steel-framed clunkers. Hooray for friction! Oh and if you’re happy with the location you could always get rid of the clamp and screw it in place instead.

Simple? Yup. Effective? Totally.

Oh and if it’s still crummy old winter where you live, why not beat the cold weather blues with an indoor bicycle roller?


Filed under: misc hacks, transportation hacks

DIY Turntable In A Beautiful Wooden Case

อังคาร, 03/10/2015 - 09:00

Old timers who have been around for the last 40 years or so have been fortunate enough to have lived through several audio reproduction technologies – Vinyl Records, Cassette Tapes, Laser Disks and CD-ROM’s. Most will also swear that analog, especially vinyl records, sounded the best. And when it comes to amplifiers, nothing comes close to the richness of vacuum tubes.

[MCumic10] had a long time desire to build his own HiFi turntable encased in a nice wooden housing, with the electronics embedded inside. When he chanced upon an old and battered turntable whose mechanism barely worked, he decided to plunge right in to his pet project. The result, at the end of many long months of painstaking work, is a stunning, beautiful, wooden turntable. Especially since in his own words, “I didn’t have any experience in electronics or woodworking before I started this project so it took me many long months in learning analyzing and frustration. I burned some electronic parts few times and made them from the beginning.”

The build is a mix of some off the shelf modules that he bought off eBay and other sources, and some other modules that he built himself. He’s divided the build in to several bite sized chunks to make it easy to follow. The interesting parts are the 6N3 Valve Preamplifier (the main amplifier is solid-state), the motorized Remote Volume Control Input kit, and the Nixie tube channel indicator. And of course the layered, plywood casing. By his own reckoning, this was the toughest and longest part of his build, requiring a fairly large amount of elbow grease to get it finished. He hasn’t yet measured how much it tips the scales, but it sure looks very heavy. The end result is quite nice, especially for someone who didn’t have much experience building such stuff.

Thanks [irish] for sending in this tip.


Filed under: home entertainment hacks

3D Printer Plays Classic MIDIs

อังคาร, 03/10/2015 - 06:00

For whatever reason we all seem to have this obsession with making things other than speakers into speakers. Hard drives, floppy drives, CD drives, fax machines, inanimate objects, dot-matrix printers, and now — well let’s stay with times — a 3D printer!

[Andrew Sink] wanted to give stepper music a try (is that seriously a genre now? (Yes, we’re calling it Stepstep – Ed.)), so he found HomeConstructor.de, which happens to have an awesome MIDI to G-CODE converter specifically designed for making those steppers hum. His instrument of choice is an original Printrbot but unfortunately it did require a few hours of tweaking the G-Code to get it to work just right.

Feast your ears on this beautiful rendition of the Jurassic Park Theme song below.

Not useless cool enough for you? How about a calculator playing music on a floppy drive? A CNC machine music factory? No? How about some freakin’ lasers playing the Super Mario Bros theme?


Filed under: 3d Printer hacks

Execution Tracing on Cortex-M3 Microcontrollers

อังคาร, 03/10/2015 - 03:00

The higher-power ARM micros have a bunch of debugging tools for program and data tracing, as you would expect. This feature – CoreSight Trace Macrocells – is also found in the lowly ARM Cortex M3 microcontroller. The Cortex M3 is finding its way into a lot of projects, and [Petteri] wondered why these debugging tools weren’t seen often enough. Was it a question of a lack of tools, or a lack of documentation? It doesn’t really matter now, as he figured out how to do it with a cheap logic analyzer and some decoders for the trace signals.

There are two trace blocks in most of the Cortex M3 chips: the ITM and ETM. The Instrumentation Trace Macrocell is the higher level of the two, tracing watchpoints, and interrupts. The Embedded Trace Macrocell shows every single instruction executed in the CPU.  Both of these can be read with a cheap FX2-based logic analyzer that can be found through the usual outlets for about $10. The problem then becomes software, for which [Petteri] wrote a few decoders.

To demonstrate the debugging capability, [Petteri] tracked down a bug in his CNC controller of choice, the Smoothieboard. Every once in a great while, the machine would miss a step. With the help of the trace tool and by underclocking the micro, [Petteri] found the bug in the form of a rounding error of the extruder. Now that he knows what the bug is, he can figure out a way to fix it. He hasn’t figured that out yet. Still, knowing what to fix is invaluable and something that couldn’t be found with the normal set of tools.


Filed under: ARM

Logic Noise: Sawing Away with Analog Waveforms

อังคาร, 03/10/2015 - 00:01

Today we’ll take a journey into less noisy noise, and leave behind the comfortable digital world that we’ve been living in. The payoff? Smoother sounds, because today we start our trip into analog.

If you remember back to our first session when I was explaining how the basic oscillator loads and unloads a capacitor, triggering the output high or low when it crosses two different thresholds. At the time, we pointed out that there was a triangle waveform being generated, but that you’d have a hard time amplifying it without buffering. Today we buffer, and get that triangle wave out to our amplifiers.

But as long as we’re amplifying, we might as well overdrive the amps and head off to the land of distortion. We’ll do just that and build up a triangle-wave oscillator that can morph into a square wave, passing through a rounded-over kinda square wave along the way. The triangle sounds nice and mellow, and the square wave sounds bright and noisy. (You should be used to them by now…) And we get everything in between.

And while we’re at it, we might as well turn the triangle wave into a sawtooth for that nice buzzy-bass sound. Then we can turn the fat sawtooth into a much brighter sounding pulse wave, a near cousin of the square wave above.

What’s making all this work for us? Some dead-boring amplification with negative feedback, and the (mis-)use of a logic chip to get it. After the break I’ll introduce our Chip of the Day: the 4069UB.

If you somehow missed them, here are the first three installments of Logic Noise:

The 4069UB

The 4069UB is a hex (unbuffered) inverter. In fact, if you can remember the pinout of the 40106, this should look very familiar to you. The only difference is the lack of hysteresis (and the little squiggly symbols) in the inverters. But what a difference that makes! The lack of buffering and hysteresis in the inverter lets us use the individual amplifiers for analog purposes rather than digital / logic.

Remember that the “UB” part is mandatory for all of this to work. It stands for unbuffered, and that essentially means that there’s no special attempt made to convert the output into something digital inside the chip. (Some end in “UBE” or “UBF” or whatever. As long as there’s a “UB” somewhere, you’re set.) And it turns out that an unbuffered inverter is nothing more than a push-pull CMOS amplifier pair. Each “inverter” cell looks like this:

Ignoring the input-protection diodes, you can see that it’s basically just two transistors: an N-channel FET connected between output and ground and a P-channel FET connected between output and the power rail. (That’s the Complementary MOS pair that gives CMOS chips their name.)

If you’re not brushed up on your MOSFETs, the N-channel conducts when the input gate is pulled to a high voltage, and the P-channel conducts when the input gate is pulled low. This means that when the input voltage is low, the bottom FET doesn’t conduct and the top FET does, pulling the output voltage high. And vice-versa for a high input voltage. This makes a rudimentary logic inverter. Hooray!

But what happens in-between? At mid-supply voltages, both of the transistors will be turned on to varying degrees. This makes an output voltage that’s continuous, analog, and the “opposite” of the input. In order to give the chip a decent logic output, it needs to have a high gain through this middle zone so that voltages that are just a bit higher than the midpoint result in outputs that are clearly a logic zero.

The beauty of this chip for our purposes is the soft clipping effect that you get from the S-shaped gain curve above. That is, the gain rolls off (the line is less steep) near VCC and GND. This makes for a pleasing overdrive sound as we crank the amplifier up, and lets us control the amount of fuzz on the output by controlling the input volume and gain.

Buffers and Feedback

As we said above, the naked 4096UB chip has a very high gain right around the midpoint voltage, which is what makes it useful as a logic chip. To make it useful for amplifiying analog audio, we’ll use (negative) feedback to calm this gain down a little bit. By controlling the ratio of input signal to feedback, we can vary the output from nearly completely silent to distorted out to the limits of the voltage supply.

For starters, let’s aim to get a voltage gain of -1. That is, the output signal is just as big as the input signal but opposite in sign around the mid-point. This is an “inverting unity gain buffer” if you’re an electrical engineer. And buffers will allow us to listen in to signals that our amplifier’s input circuitry would otherwise swamp out.

Remember when we said that there was a triangle wave on the input terminals of the 40106 inverter? Did you try to plug them up to your amplifier? If so, it probably didn’t work although you can see it clear as day on the oscilloscope. Even when I can get it to work, there’s still a pitch shift that depends on the volume knob settings on my amplifier. Strange stuff! Clearly, the amplifier’s input circuitry is coupling with the oscillator. Putting a buffer circuit in-between will let the oscillator oscillate and the amplifier amplify without interacting with each other. That’s what buffers do. Let’s build.

The unity-gain buffer circuit is as simple as connecting the input through a resistor and then connecting another resistor with that same value in feedback between the output and the input. For intuition on how this works, let’s dig briefly into negative feedback amplifiers.

The intuition for this circuit (and all negative feedback topologies) involves first realizing that where the input signal and negative feedback meet, there can’t be any net signal voltage above or below the chip’s neutral voltage. If there were positive net signal, the inverter output would go negative until the feedback brought the junction of the two back down to neutral. If the input is negative with respect to neutral, the output will go positive and pull it back up. When the feedback path is working as intended, it’ll hold the input at the neutral voltage level.

A quick word about this neutral voltage. If you’re familiar with op amps, the neutral voltage is whatever’s present on the positive terminal. In our case, the chip switches from high to low around the mid-rail voltage, half of VCC, so that’s our neutral point. You can demonstrate this by unplugging the input and measuring what voltage level the output (and input) settle at with no signal present. It’ll be around VCC/2.

So the first basic premise is that the feedback exactly cancels out the net signal where they meet up at the input of the inverter. This cancellation means that whatever signal current comes in through the input resistor has to get pulled on out through the feedback resistor. If you think of voltage as the force required to push a given current through a resistor, the output only has to work as hard as the input when the two resistors are equal. That is, when the input voltage is 0.1 volts above neutral, the output will be 0.1 volts below neutral because both are “fighting” the same resistance.

And there you have it: an “amplifier” with a gain of negative one. It doesn’t make the signal louder, but now you can plug the output of the buffer stage directly into your audio output and give it a listen without interference. And just for fun, this picture shows the input and output on the scope. Working as intended.

Amplifiers and Overdrive

Great. Now we’ve got a nice clean triangle wave oscillator. You’d think we were done here, but we still have five inverter gates sitting unused on the 4069UB. What could we do with five more amplifiers? Five more amplifiers that have a nice smooth rolloff much like old-school tube preamps do? Crank it up to 11 and see how it sounds!

To go from buffer circuit to amplifier circuit, we can either let the input signal flow in more easily (reduce the input resistance) or force the output to work harder (increase the feedback resistance). Either way, the goal is to increase the ratio of feedback resistor to input resistor, and thus the voltage gain.

So let’s build up another buffer circuit, but instead of a 100k Ohm resistor on the input, let’s use a 100k potentiometer so that we can let more signal in. Now it’s an amplifier, with the gain controlled by the ratio of the feedback resistor (at 100k Ohms) divided by whatever resistance we dial in on the input potentiometer. (You could use a larger pot than feedback resistor, and you’d be able to make the circuit quieter as well. But that’s boring.)

As you drop the input resistance down to zero, you’d naively expect the amplification gain to head off to infinity. Instead, we see that the gain reduces gradually as the output voltage approaches the GND or VCC power rails. What happens is that real-world effects like the chip’s amplification rolloff take over. Is this a bad thing? Not if you want a nice soft-clipping amplifier overdrive sound added to our triangle wave. Woot.

Now as long as we have a bunch of free inverters sitting around, let’s take the output from the overdrive sound and re-amplify it again. The IC’s built-in soft clipping will limit the volume gain, but we’ll get something that’s ever more like a square wave as we keep passing the signal through further amplification stages. Note that the fuzz stage runs at full gain — without negative feedback. We’re going for fuzz distortion here. For my liking, a single extra amp stage suffices to get a nice fuzz tone, but you could chain up as many stages with and without feedback as you want. Heck, half of the chip is still sitting there unused, go nuts.

Here are some example waveforms from the first-stage amplifier and the second. At the low-gain end of things, you can see that the first-stage triangle wave, in yellow, is not very distorted yet. But as we turn up the gain, the points get rounded over on top and it approaches a round square wave. (“Round square”?) The second-stage output, in green, starts off pretty much squared-out and gets more so. Between the two outputs, you have mild overdrive and full fuzz. Can’t complain about that.

The scope traces below show the overdrive output in yellow and the fuzz output in green with the volume knob turned increasingly up. You can see that the as you increase the gain, the fuzz channel takes off essentially where the overdrive channel leaves off.

And don’t hesitate to feed other audio sources into this chip. A version of this circuit dates back to the late 1970’s, known as [Craig Anderton’s] “Tube Sound Fuzz” from his book Electronic Projects for Musicians. My wasted youth doesn’t look so wasted anymore, huh?

Sawtooth Waves

OK, so we’ve got a nice variable overdrive version of the triangle wave oscillator. What else can we do with our newfound analog powers? Here, the most bang for our breadboard buck is to add a diode into the feedback path of the oscillator, turning the triangle wave into a sawtooth.

How does that work? Well, instead of charging and discharging the timing capacitor through the feedback resistor as we’ve been doing, we charge it much faster through the diode. This makes the input voltage jump up, setting the output low almost instantly. The diode only conducts in the charging direction, so the capacitor has to discharge slowly through the feedback resistor. This goes on until it hits the threshold value where the output goes high again and charges up the capacitor very quickly through the diode again. In short, we’ll end up with a voltage waveform on the input here in yellow, and on the output here in green:

Now all that’s left to do is pass this sawtooth through the buffer amplifier above. That’s that raspy, bowed-string sound that a sawtooth wave makes. Played down low, you get the classic acid-house bassline. Go nuts. But wait, there’s more. We have a sawtooth plus overdrive, plus full-on fuzz.

Below is the scope trace from medium and full gain for the overdrive output in yellow and the fuzz output in green. With the sawtooth wave, the fuzz ends up converting the sawtooth into a kind of pulse wave. It’s not symmetrically square both because our sawtooth isn’t perfectly straight and because there’s some DC offset voltage propagating through the three stages that we haven’t been careful with. If you want to remove that, you can insert something like 0.1uF blocking capacitors between the stages, but I feel you lose some of the gritty character of this thing by doing so.

Next Installment: Filters and Drums

Now that we have some classic analog synth waveforms under our belts, it’s time to add some filter effects and drums. To do so, we’ll continue down the analog path that we started this time, so if you don’t already have a couple of 4069UBs at hand, you have another week to scrounge some up.


Filed under: digital audio hacks, Featured

Ask Hackaday: The Many Uses of Microwaves

จันทร์, 03/09/2015 - 21:01

When most think of a microwave, they think of that little magic box that you can heat food in really fast. An entire industry of frozen foods has sprung up from the invention of the household microwave oven, and it would be difficult to find a household without one. You might be surprised that microwave ovens, or reactors to be more accurate, can also be found in chemistry labs and industrial complexes throughout the world. They are used in organic synthesis – many equipped with devices to monitor the pressure and temperature while heating. Most people probably don’t know that most food production facilities use microwave-based moisture solids analyzers. And there’s even an industry that uses microwaves with acids to dissolve or digest samples quickly. In this article, we’re going to look beyond the typical magnetron / HV power supply / electronics and instead focus on some other peculiarities of microwave reactors than you might not know.

Single vs Multimode

The typical microwave oven in the millions of households across the world is known as multimode type. In these, the microwaves will take on typical wavelike behavior like we learned about in physics 101. They will develop constructive and destructive interference patterns, causing ‘hot spots’ in the cavity. A reader tipped us off to this example, where [Lenore] uses a popular Indian snack food to observe radiation distribution in a multimode microwave cavity. Because of this, you need some type of turntable to move the food around the cavity to help even out the cooking. You can avoid the use of a turn table with what is known as a mode stirrer. This is basically a metal ‘fan’ that helps to spread the microwaves throughout the cavity. They can often be found in industrial microwaves. Next time you’re in the 7-11, take a look in the top of the cavity, and you will likely see one.

Multimode microwaves also require an isolator to protect the magnetron from reflected energy. These work like a diode, and do not let any microwaves bounce back and hit the magnetron. It absorbs the reflected energy and turns it into heat. It’s important to note that all microwave energy must be absorbed in a multimode cavity. What is not absorbed by the food will be absorbed by the isolator. Eventually, all isolators will fail from the heat stress. Think about that next time you’re nuking a small amount of food with a thousand watts!

Single Mode microwaves are what you will find in chemistry and research labs. In these, the cavity is tuned to the frequency of the magnetron – 2.45GHz. This allows for a uniform microwave field. There is no interference, and therefore no hot or cold spots. The microwave field is completely homogenous. Because of this, there is no reflected energy, and no need for an isolator. These traits allow single mode microwaves to be much smaller than multimode, and usually of a much lower power as there is a 100% transfer of energy into the sample.  While most multimode microwaves are 1000+ watts, the typical single mode will be around 300 watts.

Power Measurement

Most microwave ovens only produce one power level. Power is measured and delivered by the amount of time the magnetron stays on. So if you were running something at 50% power for 1 minute, the magnetron would be on for a total of 30 seconds. You can measure the output power of any microwave by heating 1 liter of water at 100% power for 2 minutes. Multiply the difference in temperature by 35, and that is your power in watts.

There are other types of microwaves that control power by adjusting the current through the magnetron. This type of control is often utilized by moisture solids analyzers, where are more precise control is needed to keep samples from burning.

Have you used a microwave and an arduino for something other than cooking food? Let us know in the comments!

Thanks to [konnigito] for the tip!


Filed under: Ask Hackaday, Hackaday Columns

Convert a Rotary Phone to VOIP using Raspberry Pi

จันทร์, 03/09/2015 - 18:01

There’s something so nostalgic about the rotary phone that makes it a fun thing to hack and modernize. [Voidon] put his skills to the test and converted one to VoIP using a Raspberry Pi. He used the RasPi’s GPIO pins to read pulses from the rotary dial – a functional dial is always a welcome feature in rotary phone hacks. An old USB sound card was perfect for the microphone and handset audio.

As with any build, there were unexpected size issues that needed to be worked around. While the RasPi fit inside the case well, there was no room for the USB power jack or an ethernet cable, let alone a USB power bank for portability. The power bank idea was scrapped. [voidon] soldered the power cord to the RasPi before the polyfuse to preserve the surge protection, used a mini-USB wifi dongle, and soldered a new USB connector to the sound card. [Voidon] also couldn’t get the phone’s original ringer to work, so he used the Raspberry Pi’s internal sound card to play ringtones.

The VoIP (SIP) was managed by some Python scripting, available at GitHub. [voidon] has some experience in using Asterisk at his day job, so it will be interesting to see if he incorporates it in the future.

[via Reddit]

 

 


Filed under: phone hacks, Raspberry Pi

Glowing LED Cubes From The Future

จันทร์, 03/09/2015 - 15:01

Sometimes people don’t believe you when you tell them something. You may have to go out of your way to convince those skeptics. Well, [AlexTheGreat] was having a hard time convincing people that he was from the future. He thought building some cool looking glowing LED cubes would help his story.

Underneath the fancy exterior covering is a cube made from pieces of clear acrylic sheet that are hot-glued together. There isn’t much inside the cube, just an LED, resistor, button cell battery and an on/off switch. A hole in one of the cube sides allows access to the on/off switch. Once all the components are verified to work, the interior of the cube is filled with hot glue to diffuse the light.

The exterior is thin sheet metal cut into cool shapes and bent around the plastic cube. Like the rest of the components, these metal covers are held on with hot glue. They do a great job of blocking the LED light ensuring it shines out of the creatively arranged gaps. We’re not sure if these will convince anyone that [AlexTheGreat] is from the future but they are certainly darn cool looking!

 


Filed under: led hacks

USB Powered CD Lamp

จันทร์, 03/09/2015 - 13:00

[Artificial Intelligence] has made a desk lamp out of parts he had kicking around in his parts bin. Most recognizable are the 4 CDs that make up the base and the shade. To start this project, [Artificial Intelligence] sketched out a circular pattern on one of the CDs and marked 7 locations where the LEDs will be. Holes were drilled at those marked locations, the LEDs inserted and hot glued into place. Each LED has its own current limiting resistor soldered in a series configuration.

[Artificial Intelligence] mentions the resistor value was determined by a nice LED resistor calculator he found online, ledcalc.com. Then each LED/resistor combo was wired together in a parallel configuration and covered up by another CD to clean up the look and protect the wiring.

The base, like the top, is also made from 2 CDs, but this time there are 5 AA batteries underneath the CDs. These batteries don’t power the lamp, they are only used as a counterweight to prevent the lamp from tipping over. A USB cord runs to the lamp base, goes through an on/off switch and then up a pair of large-gauge solid core wire before connecting to the LED’s in the top of the lamp. The thick solid core wire acts as the only support for the lamp shade and LEDs. Since it is still just wire, the lamp can be bent to shine light in the most convenient position, as any good desk lamp would be capable of.


Filed under: home hacks

Combination Lock Made Out of Paper

จันทร์, 03/09/2015 - 10:00

Most projects we feature are of the metal/wire/wood variety, but there is an entire community devoting to making very interesting and intricate things out of paper. Imgur user [Criand] has been hard at work on his own project made entirely out of paper, a combination lock that can hold a secret message (reddit post).

The motivation for the project was as a present for a significant other, wherein a message is hidden within a cryptex-like device and secured with a combination that is of significance to both of them. This is similar to how a combination bike lock works as well, where a series of tumblers lines up to allow a notched shaft to pass through. The only difference here is that the tiny parts that make up the lock are made out of paper instead of steel.

This project could also be used to gain a greater understanding of lock design and locksport, if you’ve ever been curious as to how this particular type of lock works, although this particular one could easily be defeated by a pair of scissors (but it could easily cover rock). If papercraft is more of your style though, we’ve also seen entire gyroscopes and strandbeests made of paper!


Filed under: security hacks

Hackaday Links: March 8, 2015

จันทร์, 03/09/2015 - 07:00

Nintendo is well known for… odd… hardware integration, but this video takes it to a new level. It’s a Gamecube playing Zelda: Four Swords Adventure, a game that can use a Game Boy Advance as a controller. [fibbef] is taking it further by using the Gamecube Game Boy Advance player to play the game, and using another GBA to control the second Gamecube. There’s also a GBA TV tuner, making this entire setup a Gamecube game played across two Gamecubes, controlled with a Game Boy Advance and displayed on a GBA with a TV tuner. The mind reels.

TI just released a great resource for analog design. It’s the Analog Engineer’s Pocket Reference, free for download, if you can navigate TI’s site. There are print copies of this book – I picked one up at Electronica – and it’s a great benchtop reference.

A few months ago, a life-size elephant (baby elephants are pretty small…) was 3D printed at the Amsterdam airport. A model of the elephant was broken up into columns about two meters tall. How did they print something two meters tall? With this add-on for a Ultimaker. It flips an Ultimaker upside down, giving the printer unlimited build height. The guy behind this – [Joris van Tubergen] – is crazy creative.

And you thought TV was bad now. Here’s the pitch: take a show like Storage Wars or American Pickers – you know, the shows that have people go around, lowball collectors, and sell stuff on the Internet – and put a “Tech” spin on it. This is happening. That’s a post from a casting producer on the classic cmp message boards. Here’s the vintage computer forums reaction. To refresh your memory, this is what happens when you get ‘tech’ on Storage Wars. Other examples from Storage Wars that include vastly overpriced video terminals cannot be found on YouTube. Here’s a reminder: just because it’s listed on eBay for $1000 doesn’t mean it’ll sell on eBay for $1000.


Filed under: Hackaday Columns, Hackaday links

Motion Light In Dark Stairwell Brightens Trips To The Basement

จันทร์, 03/09/2015 - 04:00

WARNNG: Walking around in the dark could be dangerous to your health! You may bump into something or worse, take a tumble down the stairs. Safety conscious [Ganesh] has come up with a solution for us folks too lazy to manually turn on a light. It’s a simple light controlled by a motion sensor that anyone can put together.

The meat and potatoes of the build is an off-the-shelf motion sensor, the same kind that is used in a home security system. We humans emit infrared energy and that is just what this sensor ‘sees’. The motion sensor is powered by 12 VDC and has a pair of DC output leads that are used to control a relay. [Ganesh] used an standard hobby relay board with built in power spike protection diode and transistor to supply the current required to trip the relay. Closing the relay sends mains power to the AC light bulb. Both the triggering threshold and the ‘on’ time are controlled by potentiometers integrated with the motion sensor.

Check the video out after the break of the device working its magic and lighting the way to [Ganesh’s] basement dungeon…

 


Filed under: home hacks

Simple Superheterodyne SW Receiver Harks Back Almost 100 years

จันทร์, 03/09/2015 - 01:00

Early radio receivers worked on a principle called Tuned Radio frequency (TRF), patented in 1916. They weren’t very easy to use, requiring each stage to be tuned to the same frequency (until ganged capacitors made that a bit easy). The Superheterodyne design, devised in 1918, was superior, but more expensive at that time. Cost considerations led adoption of the Superhet design to lag behind TRF until almost 1930. Since then, until quite recently, the Superhet design has been at the heart of a majority of commercial radio receivers. Direct Conversion Receivers were devised around 1930, but required elaborate phase locked loops which restricted their use in commercial receivers. The point of all this background is that the Superhet design has served very well for more than 90 years, but will soon be rendered redundant once Software defined Radio (SDR) becomes ubiquitous. Which is why this study of the simple Superheterodyne shortwave receiver deserves closer study.

[Dilshan] built this two transistor and two IF transformer based superheterodyne radio designed to receive 13m to 41m bands. The whole build is assembled on a breadboard, making it easy to teach others to experiment. [Dilshan] offers very useful insights into antenna, rod coil and IF transformer parameters. To dive in to Radio architecture, check this post on Amateur Radio. And if you would like to get a closer look at Antique Radios, check this post on Restoring Antique Radios.


Filed under: radio hacks

Open Source Binary Wristwatch Is Professional Quality

อาทิตย์, 03/08/2015 - 22:00

If you want to proclaim to the world that you’re a geek, one good way to go about it is to wear a wristwatch that displays the time in binary. [Jordan] designs embedded systems, and he figured that by building this watch he could not only build up his geek cred but also learn a thing or two about working with PIC microcontrollers for low power applications. It seems he was able to accomplish both of these goals.

The wristwatch runs off of a PIC18F24J11 microcontroller. This chip seemed ideal because it included a built in real-time clock and calendar source. It also included enough pins to drive the LEDs without the need of a shift register. The icing on the cake was a deep sleep mode that would decrease the overall power consumption.

The watch contains three sets of LEDs to display the information. Two green LEDs get toggled back and forth to indicate to the user whether the time or date is being displayed. When the time is being displayed, the green LED toggles on or off each second. The top row of red LEDs displays either the current hour or month. The bottom row of blue LEDs displays the minutes or the day of the month. The PCB silk screen has labels that help the user identify what each LED is for.

The unit is controlled via two push buttons. The three primary modes are time, date, and seconds. “Seconds” mode changes the bottom row of LEDs so they update to show how many seconds have passed in the current minute. [Jordan] went so far as to include a sort of animation in between modes. Whenever the mode is changed, the LED values shift in from the left. Small things like that really take this project a step further than most.

The board includes a header to make it easy to reprogram the PIC. [Jordan] seized an opportunity to make extra use out of this header. By placing the header at the top of the board, and an extra header at the bottom, he was able to use a ribbon cable as the watch band. The cable is not used in normal operation, but it adds that extra bit of geekiness to an already geeky project.

[Jordan] got such a big response from the Internet community about this project that he started selling them online. The only problem is he sold out immediately. Luckily for us, he released all of the source code and schematics on GitHub so we can make our own.


Filed under: clock hacks, Microcontrollers