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AT to XT Keyboard Adapter

อาทิตย์, 01/22/2017 - 04:01

If you got an old PC/XT stored somewhere in basement and want to use a newer keyboard, here’s a little project you might like. [Matt] built an AT2XT keyboard adapter on a prototype board using an AT to PS/2 keyboard cable. An AT2XT keyboard adapter basically allows users to attach AT keyboards to XT class computers, since the XT port is electronically incompatible with PC/AT keyboard types. For those retro computing fans with a lot of old PCs, this trick will be great to connect the XT machines to a KVM (keyboard/Video/Mouse) switch.

[Matt] found schematics for the project on the Vintage Computer Federation Forum, but used a PIC12F675 instead of the specified PIC12F629. He does provide the .hex file for his version but unfortunately no code. You could just burn the .hex file or head up to the original forum and grab all files to make your own version. The forum has the schematics, bill of materials, PCB board layout and firmware (source code and .hex), so you just need to shop/scavenge for parts and get busy.

And if you are felling really 31337, you can make a PS/2 version of the binary keyboard to justify the use of your new adapter.

[via DangerousPrototypes]

Filed under: computer hacks, hardware

Persistence Of Vision Death Star

อาทิตย์, 01/22/2017 - 01:01

Death Stars were destroyed twice in the Star Wars movies and yet one still lives on in this 168 LED persistence of vision globe made by an MEng group at the University of Leeds in the UK. While Death Stars are in high demand, they mounted it on an axis tilted 23.4° (the same as the Earth) so that they can show the Earth overlaid with weather information, the ISS position, or a world clock.

More details are available on their system overview page but briefly: rotating inside and mounted on the axis is a Raspberry Pi sending either video or still images through its HDMI port to a custom made FPGA-based HDMI decoder board.  That board then controls 14 LED driver boards mounted on a well-balanced aluminum ring. All that requires 75W which is passed through a four-phase commutator. Rotation speed is 300 RPM with a frame rate of 10 FPS and as you can see in the videos below, it works quite well.

This isn’t the first POV Death Star we’ve seen here. [Jason] made a smaller one using his own rotating PCB that can be described only as awesome.

[via Adafruit]

Filed under: Raspberry Pi

Lego Boosts Their Robotic Offering

เสาร์, 01/21/2017 - 23:31

Kids often have their first exposure to robots in school using Lego Mindstorm kits. Now Lego is rolling out Boost — a robotic kit targeting all Lego builders from 7 years old and up. The kit is scheduled to be on the market later this year (it appeared at the recent CES) and will sell for about $160.

[The Brothers Brick] had a chance to try the kit out at CES (see the video below) and you might find their review interesting. The kit provides parts and instructions to build five different models: a cat, a robot, a guitar, a 3D printer, and a tracked vehicle. You can check out the official page, too.

The system communicates with an Apple or Android tablet via Bluetooth. The review notes that the programming language is a bit simplistic, allowing actions to occur due to stimulus, but no real conditional tests and branches. In addition to motor control, the device comes with blocks that can sense motion and color (see right). Builders can integrate the blocks with other Lego designs, too.

We’ve seen lots of additions and enhancements to Mindstorms (along with lots of interesting applications). It will be interesting to see what hacks appear for Boost.

Filed under: Microcontrollers, robots hacks

A Motherboard Manufacturer’s Take On A Raspberry Pi Competitor

เสาร์, 01/21/2017 - 22:00

In the almost five years since the launch of the original Raspberry Pi we have seen a huge array of competitors emerge in the inexpensive single board computer market. Many have created their own form factors, but an increasing number have gone straight for the jugular of the fruity board from Cambridge by copying its form factor and interfaces as closely as possible. We’ve seen sterling efforts from the likes of Banana Pi, Odroid, and several others, but none have yet succeeded in toppling it from its pedestal.

The ASUS Tinker specification.

The latest contender in this arena might just make more of an impact though, because it comes from a major manufacturer, a name you will have heard of. Asus have quietly released their Tinker, board that follows the Pi form factor very closely, and packs a 1.8 GHz quad-core ARM Cortex A17 alongside an impressive spec we’ve captured as an image for this article. Though they are reticent about it on their website, there is a SlideShare presentation with some of the details, which we’ve placed below the break.

At £55 (about $68) where this is being written it’s more expensive than the Pi, but Asus go to great lengths to demonstrate that it is significantly faster. We will no doubt verify the accuracy of that claim as the boards find their way into the hands of our community. Still, it features a mostly-Pi-compatible I/O header, and the same display and camera connectors as the Pi. There is no information as to how compatible these last two are though.

Other boards in this arena have boasted impressive hardware, but have fallen down when it comes to the support for their operating systems. When you buy a Raspberry Pi it is not just the hardware you are taking on but the Raspbian operating system and its impressive community support. The Tinker supports Debian, so if Asus is to make a mark they must ensure that its support rivals that of the board it is targeting. If they succeed in that endeavor then the result can only be good news for us.

Asus Tinker Board from Niyazi SARAL

To get an idea of the products the Tinker is up against, read our Raspberry Pi 3 and Odroid C2 reviews from last year. But don’t take all our SBC coverage so seriously.

Thanks [Mynasru].

Header image: the CPC catalogue page linked above.

Filed under: computer hacks, news

DreamBlaster X2: A Modern MIDI Synth for Your Sound Blaster Card

เสาร์, 01/21/2017 - 19:01

Back in the 90s, gamers loaded out their PCs with Creative’s Sound Blaster family of sound cards. Those who were really serious about audio could connect a daughterboard called the Creative Wave Blaster. This card used wavetable synthesis to provide more realistic instrument sounds than the Sound Blaster’s on board Yamaha FM synthesis chip.

The DreamBlaster X2 is a modern daughterboard for Sound Blaster sound cards. Using the connector on the sound card, it has stereo audio input and MIDI input and output. If you’re not using a Sound Blaster, a 3.5 mm jack and USB MIDI are provided. Since the MIDI uses TTL voltages, it can be directly connected to an Arduino or Raspberry Pi.

This card uses a Dream SAM5000 series DSP chip, which can perform wavetable synthesis with up to 81 polyphonic voices. It also performs reverb, chorus, and equalizer effects. This chip sends audio data to a 24 bit DAC, which outputs audio into the sound card or out the 3.5 mm jack.

The DreamBlaster X2 also comes with software to load wavetables, and wavetables to try out. We believe it will be the best upgrade for your 486 released in 2017. If you’re interested, you can order an assembled DreamBlaster. After the break, a review with audio demos.

Filed under: digital audio hacks

Hidden Bookshelf Door Shows Incredible Motion

เสาร์, 01/21/2017 - 16:01

Who didn’t dream of a hidden door or secret passage in the house when they were kids? Some of us still do! [SPECTREcat] had already built a secret door in a fully functioning bookcase with a unique opening mechanism. The intriguing mechanism allows the doors to start by sliding slightly away form one another before hinging into the hidden space. Their operation was, however, was manual. The next step was to automate the secret door opening mechanism with electronics.

The project brain is an off-the-shelf Arduino Uno paired with a MultiMoto Arduino shield to drive 4 Progressive Automations PA-14 linear actuators. These linear actuators have 50lb force, allowing the doors to fully open or close within 10 seconds and maintain a speed that wouldn’t throw the books off the bookcases.

Not wanting to drill a hole through the bookshelf for a switch or other opening mechanisms, [SPECTREcat] added a reed switch that is activated on the other side by a DVD cover with a magnet inside. In addition to that, there is a PIR sensor on the inside room to automatically close the doors if no motion is detected for 2 hours. Dont worry, there’s also a manual switch inside just in case.

Using one of the items on the shelf to trigger the secret passage is a classic move. He could also have used a secret knock code, like the Secret Attic Library Door we covered in the past. Check out the video below to see the hinge and slide movement in action.

Filed under: home hacks

Voice at 700 Bits Per Second

เสาร์, 01/21/2017 - 13:00

All other things being equal, signals with wider bandwidth can carry more information. Sometimes that information is data, but sometimes it is frequency. AM radio stations (traditionally) used about 30 kHz of bandwidth, while FM stations consume nearly 200 kHz. Analog video signals used to take up even more space. However, your brain is a great signal processor. To understand speech, you don’t need very high fidelity reproduction.

Radio operators have made use of that fact for years. Traditional shortwave broadcasts eat up about 10kHz of bandwidth, but by stripping off the carrier and one sideband, you can squeeze the voice into about 3 kHz and it still is intelligible. Typical voice codecs (that is, something that converts speech to digital data and back) use anywhere from about 6 kbps to 64 kbps.

[David Rowe] wants to change that. He’s working on a codec for ham radio use that can compress voice to 700 bits per second. He is trying to keep the sound quality similar to his existing 1,300 bit per second codec and you can hear sound samples from both in his post. You’ll notice the voices sound almost like old-fashioned speech synthesis, but it is intelligible.

Your ears are not linear with respect to frequency response, and the codec takes advantage of this, sampling more low frequencies than high frequencies. There are other specialized signal processing and filtering steps taken to improve the audio quality. Here’s the block diagram (you can find out more at the original post):

Tight bandwidth has lots of advantages: more channels per given frequency band, less interference, and improved resistance to noise. A 700 Hz audio signal able to carry speech would have major implications for radio communications by voice.

The codec is destined for integration with FreeDV. We’ve talked before about the wealth of technology ham radio produces. Perhaps others will find use for this codec in other situations that are not ham radio-related.

Thanks to [Rob] for pointing this out.

Filed under: radio hacks

Illuminating New Take on Magnetic Switches

เสาร์, 01/21/2017 - 10:00

While there’s something to be said for dead-bug construction, hot glue, and other construction methods that simply get the job done, it’s inspiring to see other builds that are refined and intentional but that still hack together things for purposes other than their original intent. To that end, [Li Zanwen] has designed an interesting new lamp that uses magnets to turn itself on in a way that seems like a magnetic switch of sorts, but not like any we’ve ever seen before.

While the lamp does use a magnetic switch, it’s not a traditional switch at all. There are two magnetic balls on this lamp attached by strings. One hangs from the top of the circular lamp and the other is connected to the bottom. When this magnet is brought close to the hanging magnet, the magnetic force is enough to both levitate the lower magnet, and pull down on a switch that’s hidden inside the lamp which turns it on. The frame of the lamp is unique in itself, as the lights are arranged on the inside of the frame to illuminate the floating magnets.

While we don’t typically feature design hacks, it’s good to see interesting takes on common things. After all, you never know what’s going to inspire your next hackathon robot, or your next parts drawer build. All it takes is one spark of inspiration to get your imagination going!

Filed under: home hacks

Plus Size Watch with a Pair of Tiny Nixies

เสาร์, 01/21/2017 - 07:00

When you stuff a pair of Nixie tubes into a wristwatch the resulting timepiece looks a little like Flavor Flav’s necklace. Whether that’s a good thing or not depends on your taste and if you’re comfortable with the idea of wearing 200 volts on your wrist, of course.

As a build, though, [prototype_mechanic]’s watch is worth looking into. Sadly, details are sparse due to a computer issue that ate the original drawings and schematics, but we can glean a little from the Instructables post. The case is machined out of solid aluminum and sports a quartz glass crystal. The pair of IN-16 tubes lives behind a bezel with RGB LEDs lighting the well. There’s a 400mAh LiPo battery on board, and an accelerometer to turn the display on with a flick of the wrist.

It may be a bit impractical for daily use, but it’s a nicely crafted timepiece with a steampunk flair. Indeed, [prototype_mechanic] shows off a few other leather and Nixie pieces with four tubes that certainly capture the feel of the steampunk genre. For one with a little more hacker appeal, check out this Nixie watch with a 3D-printed case.

Filed under: clock hacks

Brain Controlled Tracked Robot

เสาร์, 01/21/2017 - 04:00

[Imetomi] found himself salvaging a camera from a broken drone when he decided to use it in a new project, a tracked robot with a live video feed from the mounted camera.

… I had a cheap Chinese drone that was broken, but its camera seemed to be operating and when I took apart my drone I found a small WiFi chip with a video transmitter. I (decided) that I will use this little circuit for a project and I started to buy and salvage the parts.

Being a tracked robot, it can negotiate most types of terrain and climb hills up to 40 degrees. It is powered by two 18650 lithium-ion batteries with a capacity of 2600 mAh and the remote control is based on the HC-12 serial communication module. You can control it with a joystick and watch the camera’s live-stream in a virtual reality glass. That’s pretty neat but it’s not all.

[Imetomi] also used a hacked Nacomimi Brainwave Toy to make a brain controlled version of his robot. The brainwaves are detected using sensors placed on the scalp. To actually control it the operator has to focus on the right hand to move right, focus on the left hand to move left, blink to move forward and blink again to stop. There is also an ultrasonic sensor to help navigation so the robot doesn’t bump into things. It’s not very precise but you can always build the joystick version or, even better, make a version with both controls.

We covered an Arduino brain computer interfaces way back in 2009 and the suggestion we made was a brain controlled beer bot. But this is quite cool too. You can find the build instructions here. If you build one, lets us know how the brain control works for you.

[via arduino.cc]

Filed under: robots hacks

Multiextrusion 3D Printing and OpenSCAD

เสาร์, 01/21/2017 - 01:01

In a recent posting called Liar’s 3D Printing, I showed you how you can print with multiple filament colors even if your printer only has one extruder and hot end. It isn’t easy, though, and a lot of models you’ll find on sites like Thingiverse are way too complicated to give good results. An object with 800 layers, each with two colors is going to take a lot of filament changes and only the most patient among us will tolerate that.

What that means is you are likely to want to make your own models. The question is, how? The answer is, of course, lots of different ways. I’m going to cover how I did the two models I showed last time using OpenSCAD (seen below). The software is actually really well suited for this hack, making it easy for me to create a framework of several models to represent the different colors.

About OpenSCAD

I’m not going to say much about OpenSCAD. It is less a CAD package and more a programming language that lets you create shapes. We’ve covered it before although it changes from time to time so you might be better off reading the official manual.

The general idea, though, is you use modules to create primitives. You can rotate them and translate them (that is, move them). You can also join them (union) and take the difference of them (difference). That last is especially important. For example, look at the callsign plate above. Forget the text for now. See the two holes? Here’s the OpenSCAD that creates that shape:

difference() { cube([basew,basel,basez]); // cut holes translate([4,basel/2,0]) cylinder(r=2,h=basez+2); translate([basew-4,basel/2,0]) cylinder(r=2,h= basez+2); }

The cube “call” creates the base. The cylinders are the holes and the difference “call” is what makes them holes instead of solid cylinders (the first thing is the solid and everything after is taken away). One key point: instead of numbers, the whole thing uses (mostly) variables. That means if you change the size of something, everything will adjust accordingly if you wrote the script well. Let’s look at applying these techniques for multiple colors.

Two Colors

To drive a printer with two extruders (or one you are lying about) you need to generate two different STL files, one for each extruder. That means that it is very likely one of them is going to be just “floating” in the air and that’s OK because, in reality, it will have the other color under it.

There are lots of ways you could accomplish this. I made a simplifying assumption: Your object will mainly be one color and then you’ll have one or more colors as part of the object. Then I wrote a simple framework consisting of several OpenSCAD modules.

In OpenSCAD, what you think of as functions are called modules. There are three modules in the framework you have to worry about: object_1, object_2, and object_3. Essentially, you put the OpenSCAD code in those modules that refer to each color you want. Here’s the code for the test box (I left object_3 empty):

module object_1() // first object, main color { cube([basew,basel,basez]); } module object_2() // 2nd objects { translate([basew/2,basel/2-5*dotr,basez-dothi/2]) cylinder(r=dotr,h=dothi,center=true); translate([basew/2,basel/2+5*dotr,basez-dothi/2]) cylinder(r=dotr,h=dothi,center=true); translate([basew/2,basel/2,basez/2]) rotate([0,90,0]) cylinder(r=dotr,h=basel,center=true); }

The first two cylinders are the top spots. They just translate up to the right spot. The third cylinder is rotated and appears in the middle of the box. Keep in mind that every layer that has a colored dot is going to take a filament change. Not a problem if you really have two extruders, but if you are lying, each tool change is some manual work as you pause and manually swap colors on your single head.

Getting the STLs

There is one more thing you have to change to get things to work. At the bottom of the framework file there are some lines that are mostly commented out:

// ******************************** // To generate, pick one of these and render (F6) // then if you picked one of the create_* you can // export to STL. No need to export the preview //preview_obj(); create_obj1(); //create_obj2(); //create_obj3();

Only one of these lines should be uncommented at any given time. When you are doing your design, leave preview_obj uncommented. This will let you see the entire object with different colors for each piece.

When you are ready to create the STL files, comment out the preview line and uncomment one of the create lines. Then render using F6 (the full render). When it completes, export the STL file and then replace the comment on the line and uncomment the next line. Then repeat the F6 render and the export. In this case, you don’t have to do object 3 because there’s nothing in it.

What Happens?

The rest of the framework is pretty simple. When you do the create on object 1, it draws your object and subtracts out all the places that should be another color. The other two create calls simply render the objects you specify. I’ve assumed that you won’t have any parts of color 2 and color 3 that intersect. If you did, you’d have to do something more complicated (that is, subtract out the third object from the second; it wouldn’t be that hard).

That’s it. If you can model in OpenSCAD you can create multiple extrusion models. If you lie, you can print them on a single extrusion printer, just like I did. I haven’t tried it, but you ought to be able to use the 2nd color to cut away overhangs, and the 3rd color to build custom support structures. Then you would simply not export the 2nd color and proceed as a normal two-color print.

Obviously, this isn’t the only way to do it. In fact, it isn’t even the only way to do it in OpenSCAD. But it is a handy way to make simple multicolor models that are suitable for use with the liar’s printing method. If you don’t want to install OpenSCAD you could try your browser or you might be able to do a similar thing with OpenJSCAD.

Filed under: 3d Printer hacks, Hackaday Columns, Skills

Cheating at 5V WS2812 Control to Use 3.3V Data

ศุกร์, 01/20/2017 - 23:31

If you’re looking to control WS2812 (or Neopixel) LEDs using a microcontroller running at 3.3 volts, you might run into some issues. The datasheet tells us that a logic high input will be detected at a minimum voltage of 0.7 * Vcc. If you’re running the LED at 5V, this means 5 V * 0.7 = 3.5 V will be needed for the WS2812 to detect a ‘1’ on the data line. While you might get away with using 3.3 V, after all the specification in the data sheet is meant to be a worst case, it’s possible that you’ll run into reliability issues.

So usually we’d say “add a level shifter to convert 3.3V to 5V” and this post would be over. We even have a whole post on building level shifters which would work fine for this application. However [todbot] at CrashSpace came up with a nifty hack that requires fewer components yet ensures reliability.

For the Big Button project at CrashSpace, [todbot] used an ESP8266 running at 3.3 volts and WS2812 LEDs running at 5 V. To perform the level shift, a signal diode is placed in series with the power supply of the first LED. This drops the first LED to 4.3 V, which means a 4.3 V * 0.7 = 3.01 V signal can be used to control it. The logic out of this LED will be at 4.3 V, which is enough to power the rest of the LEDs running at 5 V.

This little hack means a single diode is all that’s needed to control 5 V LEDs with a 3.3 V microcontroller. The first LED might be a little less bright, since it’s operating at a lower voltage, but that’s a trade off [todbot] made to simplify this design. It’s a small part of a well-executed project so be sure to click-through and enjoy all the thought [todbot] put into a great build.

Filed under: led hacks

Hackaday Dictionary: Open- and Closed-Loop Systems

ศุกร์, 01/20/2017 - 22:01

Today on Hackaday Dictionary, we’re going to talk about the two basic types of control systems: open-loop and closed-loop. We’ll describe the differences between them and explore the various advantages and disadvantages of each. And finally, we’ll talk about what happens when you try to draw a line between the two.


And there was much rejoicing. Image via Racoon Valley Electric Cooperative Control Systems

Control systems are literally all around us. They’re illuminating our rooms, laundering our unmentionables, and conspiring to make us late for work. Most of us probably use or interact with at least five control systems before we’re even out the door in the morning. Odds are you’re using a control system to read this article.

When we say ‘control system’, we’re speaking broadly. A control system is defined as any system that exhibits control over a function. It doesn’t matter how big or small the function is. A standard light switch is a simple type of control system. Flip it back and forth and the light is either on or off with no in between. Too bright? Too bad. There is no way to account for light intensity preference, use duration, energy output, or anything else.

A humble clothes dryer. Image via Showplace Rents

Another common example in discussing control system theory is the clothing dryer. Set the timer on the dryer and it will run until time expires. Will it run long enough to dry everything without shrinking anything? The only way to know is to open the door and check.

Both the light switch and the clothes dryer are open-loop systems. The process is a straight line from start to finish, and they operate without concern for their output. Once the light switch is flipped to the on position, current will flow until the switch is reversed. The switch doesn’t know if the bulb is burned out or even screwed into the socket to begin with. And the clothes dryer doesn’t care if your clothes are damp or dry or totally shrunken when time runs out.


Stay in the Loop

In a closed-loop system, the process begins the same way it does in an open-loop system. But a closed-loop system has one or more feedback loops in place that can adjust the process. Sometimes the feedback will simply cause the process to repeat until the desired result is achieved.

Both of our open-loop control system examples above could easily be converted to closed-loop systems. A more advanced light switch might take input from a photo cell, or it could poll a motion detector and turn the lights off after a period of no detectable activity in the room. The clothes dryer could be improved with the addition of a moisture sensor. Since the humidity level in the dryer will change during the cycle, why not poll a DHT22 and re-run the process until a predetermined humidity level is reached? Then the dryer becomes a closed-loop system. No more reaching in and fondling the towels and shirt collars to make sure everything is dry. Well, at least in theory.

What are they telling you? xkcd #1116

Some control systems exist in both forms. Traffic lights are a good example of this phenomenon. Some lights are open-loop and simply run on a schedule. Many more of them are closed-loop and will cycle differently depending on traffic flow or information received from other traffic lights. The really smart ones have Emergency Vehicle Preemption (EVP) receivers. This is the system that allows fire trucks and some other emergency vehicles to change the lights in their favor. A device in the vehicle strobes a specific pattern at the receiver module on the light post, and the light changes as soon as possible.


Cruise control via Wikipedia Advantages and Disadvantages

The main advantage of closed-loop systems is fairly obvious: using feedback means more and better control. But there are trade-offs. It’s almost impossible to deal with all the what-ifs in creating any system, and this generates unforeseen issues. They aren’t all bad, though. Maybe you’re sitting peacefully in the corner engrossed in a book, and the motion detector-driven lights shut off because you aren’t moving around enough.  That isn’t ideal, but it’s easy enough to turn the lights back on and keep reading.

The unforeseen issues can be so much worse than sudden darkness. Case in point: robotic vacuum cleaners. Here you have a complexly closed-loop system to take care of one of life’s drudgeries. Should be awesome, right? Yes, but because it is blind to everything but its pre-programmed boundaries, it doesn’t know not to spread messes around.

A lot of closed-loop control systems look great on paper, but their imperfections become clear in execution. Take cruise control for example. Here is a system that’s better at its job than humans are. It will maintain the set speed until you hit the brakes or run out of gas. It will perform as intended whether there is a headwind or a tailwind or you’re towing a boat or transporting rowdy children. But cruise control isn’t aware of cliffs or guard rails or deer darting out in front of the car. Cruise control keeps its head down and does its job until it can’t go on.

Open-loop systems may not be as smart as closed-loop systems, but they often shine in their simplicity. For the most part, they do what you expect them to do. Light goes on, light goes off. And they are arguably more dependable since there are fewer things that can go wrong. Of course, a “simple” open-loop control system can mean a steeper learning curve. It’s not easy to learn to drive a manual transmission. But if you don’t know how to drive one, you’re missing out on some nice advantages, like the ability to push start the thing if you have to, and the option to downshift instead of pumping the brakes in icy conditions. So the question is this: is an open-loop system more valuable than a closed-loop system if it means having more control over the process? Does it depend entirely on the process in question?

This tricycle is simultaneously safe and unsafe. Image via Apple Door Open-Loop vs. Closed-Loop

So where exactly does open-loop end and closed-loop begin? The line seems clear for some systems, but muddy for others. How much feedback is enough to qualify? Add just about anything to a light switch and it seems safe to say that you took it from open- to closed-loop.

More often than not, the line between the two is blurry. Think of a motorized garage door.  You push the button and the door either opens or closes. Push it again and the door moves in the opposite direction. Most modern garage doors have a fail-safe in place to stop the garage door in the event of an emergency. If the door encounters any resistance, it will stop and reverse direction.

The break beam detector is supposed to keep people and their tricycles from being crushed if they happen to be in the way while the door is closing. But it only works if the person or thing breaks the IR beam. There’s only one beam, and it sits about six inches off the floor. The motorized garage door system is actually quite limited because it has no positional awareness. It doesn’t know where it is on the track, it’s just going up and down blindly, waiting for input or resistance.

Not all doors can be counted on to stop if they feel resistance—I tested mine and it kept on going. So if I don’t pull far enough into the garage and then put the door back down, it might hit the protruding rear end of my hatchback. It’s in the way of the door closing, but it sits way too high to break the beam. So is the garage door really, truly a closed-loop system?

Filed under: Hackaday Columns

New Lathe Day is Best Day

ศุกร์, 01/20/2017 - 19:01

As [Quinn Dunki] rightly points out, modern industrial civilization was probably conceived on the bed of a lathe. Turning is an essential step in building every machine tool, including lathes, and [Quinn] decided it was time to invite one into her shop. But she discovered a dearth of information to guide the lathe newbie through that first purchase, and thus was born the first installment in her series on choosing and using a new lathe.

As for the specifics of the purchase, [Quinn]’s article goes into some depth on the “old US iron” versus “new Asian manufacture” conundrum. Most of us would love an old South Bend or Cincinnati lathe, but it may raise practical questions about space planning, electrical requirements, and how much work is needed to get the old timer working again. In the end, [Quinn] took the path of least resistance and ordered a new lathe of Chinese heritage. She goes into some detail as to what led to that decision, which should help other first-timers too, and provides a complete account of everything from uncrating to first chips.

Nothing beats the advice of a grizzled vet, but there’s a lot to be learned from someone who’s only a few steps ahead of her intended audience. And once she’s got the lathe squared away, we trust she’ll find our tips for buying a mill helpful getting that next big shipment delivered.

“All the best things in life arrive on a pallet.” Have truer words ever been spoken? Sure, when the UPS truck pulls up with your latest Amazon or eBay treasure, it can be exciting. But a lift-gate truck rolling up to the curb? That’s a good day.

Filed under: tool hacks

Sentry Robot Turns Bad Cat to Good

ศุกร์, 01/20/2017 - 16:01

The household of [James Watts] has cats, and those cats have decided that various spots of carpet are just great for digging up with their claws. After some efforts at training the cats, [James] enlisted a robotic cat trainer with remote wireless sensors. The automated trainer does only one job, but it does that one job reliably and tirelessly, which is just what is needed in this case. A task like “automate training the cats to stop clawing the carpet” is really made up of many smaller problems, and [James] implemented a number of clever ideas in his solution.

First of all, the need for an automated solution has a lot to do with how pets form associations, and the need to have the negative reinforcement be in the right place at the right time to be effective. A harmless spritz of water in this case is used for correction and needed to be applied immediately, consistently, and “from out of nowhere” (instead of coming from a person.) Otherwise, as [James] discovered, spraying water when the cats clawed the carpet simply meant that they stopped doing it when he was around.

There were a number of tricky problems to solve in the process. One was how to reliably detect cats actually clawing the carpet. Another was how to direct the harmless spray of water to only the spot in question, and how to rig and manage a water supply without creating another mess in the process. Finally, the whole thing needed to be clean and tidy; a hackjob with a mess of wires strung everywhere just wouldn’t do.

To achieve all this, [James] created a main sprayer unit that is wirelessly connected to remote sensor units using NRF24L01+ serial packet radios. When a remote senses that a trouble spot is being clawed, the main unit uses an RC servo to swivel a spray nozzle in the correct direction and give the offending feline a watery reminder.

The self-contained remote sensors use an accelerometer to detect the slight lifting of the carpet when it’s being clawed. [James] programmed the MMA8452Q three axis accelerometer to trigger an external pin when motion is sensed above a certain threshold, and this event is sent over the wireless link.

For the main sprayer unit itself, [James] cleverly based it around an off-the-shelf replacement windshield washer tank. With an integrated pump, tubing, and assortment of nozzles there was no need to design any of those elements from scratch. If you want to give the project a shot, check out the github repository — probably worth it it since one night is all it took to change the cat behavior which explains the lack of any action video.

Pet projects usually center around automating the feeding process, but it’s nice to see other applications. For something on the positive-reinforcement end of training, check out this cat exercise wheel that integrates a treat dispenser to encourage an exercise regimen.

Filed under: home hacks, robots hacks

Recapture Radio’s Roots with an Updated Regenerative Receiver

ศุกร์, 01/20/2017 - 13:00

Crystal radios used to be the “gateway drug” into hobby electronics. Trouble was, there’s only so much one can hope to accomplish with a wire-wrapped oatmeal carton, a safety-pin, and a razor blade. Adding a few components and exploring the regenerative circuit can prove to be a little more engaging, and that’s where this simple breadboard regen radio comes in.

Sometimes it’s the simple concepts that can capture the imagination, and revisiting the classics is a great way to do it. Basically a reiteration of [Armstrong]’s original 1912 regenerative design, [VonAcht] uses silicon where glass was used, but the principle is the same. A little of the amplified RF signal is fed back into the tuned circuit through an additional coil on the ferrite rod that acts as the receiver’s antenna. Positive feedback amplifies the RF even more, a germanium diode envelope detector demodulates the signal, and the audio is passed to a simple op amp stage for driving a headphone.

Amenable to solderless breadboarding, or even literal breadboard construction using dead bug or Manhattan wiring, the circuit invites experimentation and looks like fun to fiddle with. And getting a handle on analog and RF concepts is always a treat.

[via r/electronics]

Filed under: classic hacks, radio hacks

Optimizing Linux for Slow Computers

ศุกร์, 01/20/2017 - 10:00

It’s interesting, to consider what constitutes a power user of an operating system. For most people in the wider world a power user is someone who knows their way around Windows and Microsoft Office a lot, and can help them get their print jobs to come out right. For those of us in our community, and in particular Linux users though it’s a more difficult thing to nail down. If you’re a LibreOffice power user like your Windows counterpart, you’ve only really scratched the surface. Even if you’ve made your Raspberry Pi do all sorts of tricks in Python from the command line, or spent a career shepherding websites onto virtual Linux machines loaded with Apache and MySQL, are you then a power user compared to the person who knows their way around the system at the lower level and has an understanding of the kernel? Probably not. It’s like climbing a mountain with false summits, there are so many layers to power usership.

So while some of you readers will be au fait with your OS at its very lowest level, most of us will be somewhere intermediate. We’ll know our way around our OS in terms of the things we do with it, and while those things might be quite advanced we’ll rely on our distribution packager to take care of the vast majority of the hard work.

Linux distributions, at least the general purpose ones, have to be all things to all people. Which means that the way they work has to deliver acceptable performance to multiple use cases, from servers through desktops, portable, and even mobile devices. Those low-level power users we mentioned earlier can tweak their systems to release any extra performance, but the rest of us? We just have to put up with it.

To help us, [Fabio Akita] has written an excellent piece on optimizing Linux for slow computers. By which he means optimising Linux for desktop use on yesterday’s laptop that came with Windows XP or Vista, rather than on that ancient 486 in the cupboard. To a Hackaday scribe using a Core 2 Duo, and no doubt to many of you too, it’s an interesting read.

In it he explains the problem as more one of responsiveness than of hardware performance, and investigates the ways in which a typical distro can take away your resources without your realising it. He looks at RAM versus swap memory, schedulers, and tackles the thorny question of window managers head-on. Some of the tweaks that deliver the most are the easiest, for example the Great Suspender plugin for Chrome, or making Dropbox less of a hog. It’s not a hardware hack by any means, but we suspect that many readers will come away from it with a faster machine.

If you’re a power user whose skills are so advanced you have no need for such things as [Fabio]’s piece, share your wisdom on sharpening up a Linux distro for the rest of us in the comments.

Via Hacker News.

Header image, Tux: Larry Ewing, Simon Budig, Garrett LeSage [Copyrighted free use or CC0], via Wikimedia Commons.

Filed under: software hacks

DIY Thermal Imaging Done Low-Tech Style

ศุกร์, 01/20/2017 - 07:00

[Niklas Roy] has always wanted to try out thermal imaging and saw his opportunity when he received one of those handheld IR thermometers as a gift. But not content with just pointing it at different spots and looking at the temperatures on the LCD display, he decided to use it as the basis for a scanning, thermal imaging system that would display a heat map of a chosen location on his laptop.

DIY thermal imaging system

He still wanted to to be able to use the IR thermometer as normal at a later date so cutting it open was not an option. Instead he firmly mounted a webcam to it pointing at the LCD display. He then wrote software on his laptop to process the resulting image and figure out what temperature was being displayed.

Once he got that working, he next put the thermometer on a platform with servos connected to an Arduino for slowly rotating it in the horizontal and vertical directions, also under control of the software on his laptop. Each time the thermometer measures the temperature of a spot, the software decodes the temperature on the LCD display and then tells the Arduino to use the servos to point the thermometer at the next spot to be measured. Each measurement takes a little time, so scanning an entire location as 70×44 spots takes around a half hour. But the end result is a heat map drawn on the laptop, done by a device that is low-tech. [Editor’s Snark: Because attaching a webcam and processing the images is “low-tech” these days.] He can overlay the heat map on a normal photo to see at a glance where the hot spots are.

The software he wrote is available on GitHub and the video below shows it in action. We’ve got to admit, it’s pretty awesome to watch. You can even see the heat map being filled in one measurement at a time.

[Niklas] is somewhat of a regular here on Hackaday and his projects span an impressive range of creative ideas. Check out his massive music construction machine, or his RC beer crate delivery robot, or his supersized DIY pinball machine. Whatever you do [Niklas], keep those creative juices flowing!

Filed under: misc hacks

Autodesk Moves EAGLE to Subscription Only Pricing

ศุกร์, 01/20/2017 - 04:01

EAGLE user? We hope you like subscription fees.

Autodesk has announced that EAGLE is now only available for purchase as a subscription. Previous, users purchased EAGLE once, and used the software indefinitely (often for years) before deciding to move to a new version with another one-time purchase. Now, they’ll be paying Autodesk on a monthly or yearly basis.

Lets break down the costs. Before Autodesk purchased EAGLE from CadSoft, a Standard license would run you $69, paid once. The next level up was Premium, at $820, paid once. The new pricing tiers from Autodesk are a bit different. Standard will cost $15/month or $100/year, and gives similar functionality to the old Premium level, but with only 2 signal layers. If you need more layers, or more than 160 cm^2 of board space, you’ll need the new Premium level, at $65/month or $500/year.

New Pricing Table for EAGLE

This is a bad deal for the pocket book of many users. If you could have made do with the old Standard option, you’re now paying $100/year instead of the one-time $69 payment. If you need more space or layers, you’ll likely be up to $500/year. Autodesk also killed the lower cost options for non-commercial use, what used to be a $169 version that was positioned for hobbyists.

The free version still exists, but for anyone using Eagle for commercial purposes (from Tindie sellers to engineering firms) this is a big change. Even if you agree with the new pricing, a subscription model means you never actually own the software. This model will require licensing software that needs to phone home periodically and can be killed remotely. If you need to look back at a design a few years from now, you better hope that your subscription is valid, that Autodesk is still running the license server, and that you have an active internet connection.

On the flip side of the coin, we can assume that Eagle was sold partly because the existing pricing model wasn’t doing all it should. Autodesk is justifying these changes with a promise of more frequent updates and features which will be included in all subscriptions. But sadly, Autodesk couldn’t admit that the new pricing has downsides for users:

“We know it’s not easy paying a lump sum for software updates every few years. It can be hard on your budget, and you never know when you need to have funds ready for the next upgrade.”

In their press release, they claim the move is only good for customers. Their marketing speak even makes the cliche comparison to the price of a coffee every day. Seriously.

[Garrett Mace] summarized his view on this nicely on Twitter: “previously paid $1591.21 for 88 months == $18.08/mo. Moving to $65/mo? KICAD looks better.”

We agree [Garrett]. KiCad has been improving steadily in the past years, and now is definitely a good time for EAGLE users to consider it before signing on to the Autodesk Subscription Plan™.

Filed under: news

Steve Collins: When Things Go Wrong In Space

ศุกร์, 01/20/2017 - 02:31

[Steve Collins] is a regular around Hackaday. He’s brought homebrew LIDARs to our regular meetups, he’s given a talk on a lifetime’s worth of hacking, and he is the owner of the most immaculate Hackaday t-shirt we’ve ever seen.

For the 2016 Hackaday SuperConference,  [Steve] took a break from his day job of driving spacecraft around the Solar System. As you can imagine, NASA plans on things going wrong. How do you plan for that? [Steve] answers all your questions by telling you what happens when things go wrong in space.

Space is the worst possible place for hardware. Not only do you have temperature swings of hundreds of degrees, solar radiation, and limited bandwidth, but you also can’t fix a space probe once it’s in orbit. Anyway you look at it, everything needs to go perfectly or you need to be exceptionally clever. Muphry’s Law will inevitably crop up to defeat the former, leaving the latter par for the course. This is what it’s like to work at the Jet Propulsion Lab.

Most satellites that go up are, surprisingly, very standardized. GPS satellites are built around a two or three common ‘busses’, or models. When a company wants to launch a few dozen communications satellites, the first one-off the pad won’t be much different from the last. Whenever SpaceX gets around to launching four thousand of their low orbit Internet satellites, all of those birds are going to be the same.

Deep space satellites are completely different. Each one is a custom build, and the best examples of twin deep space probes – Spirit and Opportunity on Mars, and Voyager 1 and 2 – are the exception rather than the rule. A unique piece of hardware flying around the Solar System presents a few challenges for the hardware designers. Power is always an issue, you need to plan for redundancy, and every piece of hardware needs some sort of fault protection system. Everything is a challenge in designing a deep space probe, and you need to plan for every contingency.

This is the theory of designing hardware that has to work perfectly in the worst environment imaginable, but how about some practical examples of what to do when things go wrong in space?

Throughout [Steve]’s storied career, he’s been a part of a lot of NASA missions. In the 90s, one of his jobs was planning the Deep Space 1 mission. This was a mission to a comet done on the cheap — only about $150 Million – used to demonstrate up and coming technologies like ion propulsion. While in the planning stages, [Steve] and his colleagues discussed what could go wrong. Since this was a very inexpensive mission, only one star tracker was flown on this tiny satellite.

This star tracker is important, as it’s the only thing on the spacecraft that tells the computer where it’s pointing. In the planning stages, [Steve] discussed what would happen if that star tracker died. The hypothetical solution to this problem used the science camera to point at a single star and determine the probe’s orientation. This solution sat around in the back of [Steve]’s mind for a few years until — you guessed it — the star tracker died. It wasn’t pretty, but the hack of using a science camera to determine the spacecraft’s orientation worked.

That’s a sample of what happens when things go wrong in space. What happens when things go right? Check out the video below. That’s a car, landing on Mars, with the help of a rocket-powered crane. It’s Curiosity dropping into Gale crater, and [Steve] was in the control room for this astonishing feat of engineering. He’ll be doing it again in late 2020, and with this guy at the helm we shouldn’t have much to worry about.

Filed under: cons, Featured, repair hacks