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Mechanical Image Acquisition With A Nipkow Disc

5 hours 31 minก่อน

If you mis-spent your teenage years fishing broken televisions from dumpsters and either robbing them for parts or fixing them for the ability to watch The A Team upstairs rather than in the living room as I did, then it’s possible that you too will have developed a keen interest in analogue television technology. You’ll know your front porch from your blanking interval and your colour burst, you might say.

An illustration of a simple Nipkow disk. Hzeller (CC BY-SA 3.0).

There was one piece of television technology that evaded a 1980s dumpster-diver, no 625-line PAL set from the 1970s was ever going to come close to the fascination of the earliest TV sets. Because instead of a CRT and its associated electronics, they featured a spinning disk with a spiral pattern of holes. These mechanical TV systems were quickly superseded in the 1930s by all-electronic systems, so of the very few sets manufactured only a fraction have survived the intervening decades.

The spinning disk in a mechanical TV is referred to as a Nipkow disk, after its inventor, [Paul Gottlieb Nipkow]. [Nipkow] conceived and patented the idea of a spinning disk with a spiral of holes to dissect an image sequentially into a series of lines in the 1880s, but without the benefit of the electronic amplification that would come a few decades later was unable to produce a viable system to demonstrate it. It would be in the 1920s before [John Logie Baird] would develop the first working television system using [Nipkow]’s invention.

[Baird] with his invention, showing a large Nipkow disk. The operation of a Nipkow disk is simple enough. An image is projected onto its surface across the region through which the spiral of holes pass. As the disk rotates, each of its holes traverses its own arc across the image that is immediately adjacent to that traversed by the hole before it. As each of the holes performs the traverse they gradually scan the image line by line, and when the last hole in the spiral has passed it is immediately followed by the first one at the other end of the spiral and the process is repeated. If a light-sensitive detector is placed behind the disk then it receives a light intensity that corresponds to a voltage output representing the picture as video scan lines.

If the process is reversed and a lamp is placed behind the disk and fed an amplified video signal, as each hole passes in front of it there will be displayed a new line of the picture, and due to persistence of vision in the eye of the viewer the resulting fast-moving dot of light is built up into an image.

A confocal microscope in cross-section, with the Nipkow disk being inside the casing horizontally immediately below the eyepiece. US patent US3517980A.

It is a given that a Hackaday reader is unlikely to stumble upon a Baird Televisor or other mechanical TV set. But the beauty of this technology is that a Nipkow disk is straightforward to make. The elementary school method involves marking a piece of card or similar flat material at the appropriate angles for the position of the holes and then measuring their position from the centre at each angle with a ruler, but a contemporary suggestion was to draw a spiral with the aid of a piece of piano wire wrapped round a central shaft. Alternatively Hackaday readers may wish to try creating a pattern for one programatically, this is the solution I opted for back when I was experimenting with Nipkow disks. My code – VBScript, but it was the 1990s! – has been lost in the mists of time, but it involved first drawing a ring of sync holes following a clock face demonstration script, then drawing another ring with appropriate decrease in distance from the centre for each hole.

Lest you imagine the Nipkow disks are an antiquated technology found only in museums and on the benches of mechanical TV enthusiasts, there is one field at the cutting edge of science in which they still play a part. Confocal microscopy is a technique in which a sample is scanned with a pinpoint of tightly focused light, to produce an extremely narrow depth of field and to reduce or eliminate reflections from out-of-focus parts of the sample. The Nipkow disk has been joined by laser scanning in this task, but retains an edge when a very low light intensity is required for a photosensitive sample.

An outdated method for producing low-resolution television is probably not something that will set every Hackaday reader’s pulse racing. But I’m sure I’ll not be the only member of our community with an interest in this direction. If I’ve just described you, then maybe it’s time to cut yourself a Nipkow disk, and post your mechanical TV set on hackaday.io.

Header image: H. G. Cisin [Public domain].

Filed under: classic hacks, Featured, History

Friday Hack Chat: Climate Change

พุธ, 06/28/2017 - 23:00

This Friday, we’re talking climate change. Is it possible to remove carbon from the atmosphere before most cities are underwater? What role can hackers play in alleviating climate change? It’s all going down this Friday on the Hack Chat on Hackaday.io

We’ve invited [Tito Jankowski] and [Matthew Eshed] to talk about climate change this Friday over on hackaday.io. [Tito] and [Matthew] are the founders of Impossible Labs, and they’re looking for ways to find, test, and build technology that will remove carbon from Earth’s atmosphere. Their goal is to remove 300 parts per million of carbon dioxide by 2050. Will they succeed? If someone doesn’t, you can kiss every coastal city goodbye.

Their first job is getting everyone to care. [Jankowski] thinks it can be done through better access to information and snazzy graphics — if people knew what was going on, maybe they’d give a darn. So whether you’d like to talk graphics and data or the engineering of carbon sequestration devices, this is a Hack Chat of global importance. Join us!

Here’s How To Take Part:

Our Hack Chats are live community events on the Hackaday.io Hack Chat group messaging. This Hack Chat will take place at noon Pacific time on Friday, June 30th. Confused about where and when ‘noon’ is? Here’s a time and date converter!

Log into Hackaday.io, visit that page, and look for the ‘Join this Project’ Button. Once you’re part of the project, the button will change to ‘Team Messaging’, which takes you directly to the Hack Chat.

You don’t have to wait until Friday; join whenever you want and you can see what the community is talking about.

Filed under: Hackaday Columns

Fly Across the Water on a 3D-Printed Electric Hydrofoil

พุธ, 06/28/2017 - 22:00

Paddleboards, which are surfboard-like watercraft designed to by stood upon and paddled around calm waters, are a common sight these days. So imagine the surprise on the faces of beachgoers when what looks like a paddleboard suddenly but silently lurches forward and rises up off the surface, lifting the rider on a flight over the water.

That may or may not be [pacificmeister]’s goal with his DIY 3D-printed electric hydrofoil, but it’s likely the result. Currently at part 12 of his YouTube playlist in which he completes the first successful lift-off, [pacificmeister] has been on this project for quite a while and has a lot of design iterations that are pretty instructive — we especially liked the virtual reality walkthrough of his CAD design and the ability to take sections and manipulate them. All the bits of the propulsion pod are 3D-printed, which came in handy when the first test failed to achieve liftoff. A quick redesign of the prop and duct gave him enough thrust to finally fly.

There are commercially available e-foils with a hefty price tag, of course; the header image shows [pacificmeister] testing one, in fact. But why buy it when you can build it? We’ve seen a few hydrofoil builds before, from electric-powered scale models to bicycle powered full-size craft. [pacificmeister]’s build really rises above, though.

[pacificmeister], if you’re out there, this might be a good entry in the Hackaday Prize Wheels, Wings, and Walkers round. Just sayin’.

Thanks to [Reuben] for the tip on this one.

Filed under: misc hacks, transportation hacks

Wooden Laptop Enclosure: New Life for Old Thinkpad

พุธ, 06/28/2017 - 21:00

Technology is designed to serve us and make our lives better. When a device gets outdated, it is either disposed of or is buried in a pile of junk never to be seen again. However, some individuals tend to develop a certain respect for their mechanical servants and make an effort to preserve them long after they have become redundant.

My relationship with my first laptop is a shining example of how to hold onto beloved hardware way too long. I converted that laptop into a desktop with a number of serious modifications which helped me learn about woodworking along the way. Maybe it’s more pragmatic to just buy new equipment. But you spend so much time each day using your devices. It is incredibly satisfying to have a personal connection that comes from pouring your own craftsmanship into them.

Why the Effort? IBM Thinkpad R60 via Notebook Review

The laptop in question is an IBM R60 which I lugged around during the first three years after I graduated. It was my companion during some tough times and naturally, I developed a certain attachment to it. With time its peripherals failed including the keyboard which housed the power switch and it was decided that the cost of repair would outweigh its usefulness.

Then came the faithful day when I was inspired to make something with the scrap wood that had accumulated in my workshop. This would be my second woodworking project ever and I did not have the professional heavy machinery advertised in most YouTube videos. Yet I had two targets in mind with this project.

  1. Make the R60 useful again.
  2. Learn about woodworking for creating enclosures for future projects.

Armed with mostly hand tools, a drill and a grinder that was fitted with a saw blade, I started with the IBM R60 to all-in-one PC mod. Following is a log of things I did and those I regret not doing a.k.a. lessons learned. Read on.

Patience Is Power

First things first. Since the keyboard is dead and the power switch is on the keyboard, I needed to figure out a way to turn it on. After a short Google search that turned up nothing useful, I decided to trace out the pins on the keyboard connector that could be used to trigger the operation. Trial and error resulted in the isolation of the two pins that were the key.

I ripped out the ribbon cable from the faulty keyboard and was able to solder two wires to the appropriate contacts. A PCB mount push button was chosen because my intention was to mount it to the side of the chassis. In the video below, you can see that the hack works as expected.

Hot glue is so useful in such cases and I applied generously to the cable to tack it along the chassis as well as the edge where the button finally rests. That solves the power-up problem and I intend to use an external mouse and keyboard for the finished system.

Cuts and Bruises

It is evident that the hinges had to be removed in order to be able to fold the display backward, however, another challenge awaited. The ribbon cable that connects the display to the motherboard is not designed to wrap around the enclosure like I planned and is shorter than I would have like; much shorter.

Instead of discarding the chassis and LCD covers, I made the choice that involved power tools. The idea was to cut a slot in the main chassis so as to allow the cable to easily reach its destination. After unscrewing the connector and removing it, I carefully made the necessary incision.

A cut in the battery slot, as well as the LCD back cover, was necessary and though it may not be the cleanest, it did work out. My concern here was the cable itself and as you can see in the picture above, it suffered a bit of damage.

Evolution of the Enclosure Concept

The next part was the creation of an enclosure and I wanted to use the scrap wood I had lying around. I am not an experienced carpenter, to say the least. In fact, this was my second woodworking project and I used mostly manual tools for the project. The largest part is the LCD and I took some measurements to see if I could make a small box-like enclosure.

The result was something that did not resemble an enclosure, however, I am sharing the image here because it was a starting point. The ports could all be accessed however it was not something that could be presented. I continued to test my hypothesis of the usability of the system when put to work. I installed Kali Linux since the WiFi card could be used in a multitude of ways including a honeypot for network experiments.

The hardware worked at this point leaving only the enclosure in an unfinished state.

For the final design, I chose the standard all-in-one desktop form factor and decided to cut 12mm plywood into required sizes. The thick plywood meant that the completed frame would be quite heavy but it would also give me room to trim and drill if necessary.

Before I nailed everything together, I mocked it up to see where the slots for the ports and power plug would go. This is important since cutting out holes will become very difficult after things have been stitched together.

I marked everything out before I made the cuts and measured it twice since there was no scrap wood left. Instead of putting it under a saw, I decided to use a drill with a large bit to make holes.

My decision paid off and I used a circular saw to cut the rest of the slots. Normally this kind of stuff is done with a jig saw but I used my power saw with a small wood scrap for fulcrum and it worked out nicely. The resulting slots were later filed and cleaned up with the paint job. Once I was sure everything was in place, I used wood glue and nails to make the final enclosure. I took the blurry picture above, but you get the point.

Paint it Red!

The enclosure at this point was rough and not really fit for paint. The first thing to do was to add a coat of wood primer to fill in the gaps a bit. Next, I added a coat of wood filler and then sanded it down for a smooth finish. I started with 80 grit paper and move to 220 in a total of 5 steps.

The idea is to fill in any unevenness in the wood with filler and make everything plane. I then added another coat of primer and then some red enamel. I could have chosen laminates or something else but this was an experiment and an opportunity to learn. Watching paint dry was not as fun as I had hoped but I did get a glossy smooth finish at the end.

The Face That Launched the Project

The enclosure is incomplete without the front face and I had already reserved a piece for that. The size of the display was measured and marked on the designated piece. Cutting it was tougher than I thought and it is better to shave off a bit more than required since the edge will need to be prepared later anyway.

The board was primed and painted the same as the enclosure with red enamel to match with the back. The edges could use some wooden ply edges to make things smooth but I wanted to minimize my bill of materials so this had to do.

For the border on the display window, I used some white-silver plastic corner molding I had left over in the scraps. Lucky! I cut them up to the right size to the best of my abilities and used super glue to hold them in place.

Screws and Boring Stuff

To hold things together, screws should be used but they will look ugly along the white border. Improvisation led to the addition of screw holes from the back running through the ply-board all the way to the front. I used a smaller drill bit to first make the hole (end-to-end) and then a larger bit to make a counter bore.

That was the final screw and the enclosure was missing just one detail… the Jolly Wrencher. I had one from the Hackaday Prize a few years ago and I also added a few other decals to finish the job.

Woodworking in a 3D Printing World

When we see projects with wooden boxes online we usually don’t appreciate the effort that went into creating it. I for one thought it would be easy and found it to be a messy experience as compared to 3D printing. Here are a few takeaways.

  • Try to use connectors where possible. They can save a lot of time in the long run.
  • Keep a few push buttons in stock. You already know why.
  • Be ultra-careful of cables and components. I damaged a part of the display cable and wish I had taken my own advice.
  • If you decide to cut wood manually, decide if you want to add décor (trim) later. If so then shave a bit more than you need but just a little bit.
  • Sanding takes time. There are no shortcuts to a perfect finish in woodwork.
  • Safety gear is a must. You don’t want to lose pieces of you.
  • When in doubt, get a professional advice.

My old beat up laptop got a new lease on life and I plan to use it as a desktop until something terminal happens to it. The enclosure prepared has some imperfections and those make it unique. It speaks volumes about the effort that has been put into it and has increased the sentimental value of the machine.

I have learned a bit about working with wood and will be experimenting with lumber next. The only drawback I have seen is the additional weight as opposed to plastic. The advantage of being sturdy is something that can come in handy for large volume projects. Share your projects and tips and hopefully, beginners like me will get better with time.

Filed under: computer hacks, Hackaday Columns

Copper, Brass, Mahogany, and Glass Combine in Clock with a Vintage Look

พุธ, 06/28/2017 - 18:00

No two words can turn off the average Hackaday reader faster than “Nixie” and “Steampunk.” But you’re not the average Hackaday reader, so if you’re interested in a lovely, handcrafted timepiece that melds modern electronics with vintage materials, read on. But just don’t think of it as a Nixie Steampunk clock.

No matter what you think of the Steampunk style, you have to admire the work that went into [Aeon Junophor]’s clock, as well as his sticktoitiveness –he started the timepiece in 2014 and only just finished it. We’d wager that a lot of that time was spent finding just the right materials. The body and legs are copper tube and some brass lamp parts, the dongles for the IN-12A Nixies are copper toilet tank parts and brass Edison bulb bases, and the base is a fine piece of mahogany. The whole thing has a nice George Pal’s Time Machine vibe to it, and the Instructables write-up is done in a pseudo-Victorian style that we find charming.

If you haven’t had enough of the Nixie Steampunk convergence yet, check out this Nixie solar power monitor, or this brass and Nixie clock. And don’t be bashful about sending us tips to builds in this genre — we don’t judge.

[Horatius], thanks for the tip.

Filed under: classic hacks, clock hacks

New Ransomware Crippling Chernobyl Sensors

พุธ, 06/28/2017 - 15:00

[The BBC] reports Companies all over the world are reporting a new ransomware variant of WannaCry. this time it has taken out sensors monitoring the Chernobyl nuclear disaster site.

We have all heard of the growing problem of ransomware and how Windows XP systems seem especially susceptible to WannaCry and it’s variants which were originally zero day vulnerabilities stored up by the NSA then leaked by WikiLeaks. Microsoft did release a patch. It’s been everywhere in the media but it still seems that some people didn’t get the memo.

Ukrainian state power plants and Kiev’s main airport, among others, have been affected. Probably most interesting and scary of all is that Chernobyl monitoring stations have been taken out, and monitors have to take radiation levels manually for the moment.

It seems that most reports are coming from old Soviet Bloc states (Ukraine, Russia, and Poland), which raises the question of where the attacker is based. Kaspersky Lab is reporting that it’s believed the ransomware was a “new malware that has not been seen before” with a close resemblance to Petya. So as a result, the firm has dubbed it NotPetya.

NotPetya is spreading rapidly affecting companies all over the world with no signs of slowing just yet. Will we see an end to WannaCry variants any time soon?


Filed under: news, security hacks

An Enchanted Rose For A Beauty

พุธ, 06/28/2017 - 12:00

Being a maker opens up so many doors in terms of ways to romance one’s partner through passion projects. If their passion is Disney films, then you may handily make them the enchanted rose from Beauty and the Beast for their birthday. Easy-peasy.

In addition to the love and care that went into this build, redditor [Vonblackhawk2811] has included a set of LEDs, salvaged from cheap flashlights and electronic candles, which are controlled by four toggle switches and offer multiple lighting selections — candlelight, soft white, colour cycling, and bright white — to appropriately set the mood. As if that wasn’t enough to romance his sweetheart, he’s also included an aux cord input and a pair of speakers so they may be serenaded by a tune or two as they dance the night away.

Liberal use of hot glue and duct tape are keeping the electronics secured, preventing any shorts. After all — what would it say if this gift went up in flames? An inspired stencil design — hand drawn and cut out — was used to apply a spray-on frosted glass finish to the cloche, and a romantic phrase was burned into the base, completing this heartfelt gift. The only quibble we have is that now we all have to step up our game in the courtship department.

That is, unless one is sporting the Romance Pants.

[via /r/DIY]

Filed under: misc hacks

Machine Learning IDE in Alpha

พุธ, 06/28/2017 - 09:00

Machine is an IDE for building machine learning systems using TensorFlow. You can sign up for the alpha, but first, have a look at the video below to see what it is all about.

You’ll see in the video, that you can import data for a model and then do training (in this case, to find a mustache in an image). You’ll see the IDE invites an iterative approach to development since you can alter parameters, run experiments, and see the results.

The IDE syncs with “the cloud” so you can work on it from multiple computers and roll back to previous results easily. We don’t know when the IDE will leave alpha status (or beta, for that matter), but the team’s goal is to release a free version of Machine to encourage widespread adoption.

If you want to learn more about TensorFlow, you are in the right place. We’ve also covered a bare-bones project if you’d rather get started that way. You can also find some good background material going all the way back to the early perceptron-based neural networks.

Filed under: software hacks

Dual-Purpose DIY Spot Welder Built with Safety in Mind

พุธ, 06/28/2017 - 06:00

Ho-hum, another microwave oven transformer spot welder, right? Nope, not this one — [Kerry Wong]’s entry in the MOT spot welder arms race was built with safety in mind and has value-added features.

As [Kerry] points out, most MOT spot welder builds use a momentary switch of some sort to power the primary side of the transformer. Given that this means putting mains voltage dangerously close to your finger, [Kerry] chose to distance himself from the angry pixies and switch the primary with a triac. Not only that, he optically coupled the triac’s trigger to a small one-shot timer built around the venerable 555 chip. Pulse duration control results in the ability to weld different materials of varied thickness rather than burning out thin stock and getting weak welds on the thicker stuff. And a nice addition is a separate probe designed specifically for battery tab welding — bring on the 18650s.

Kudos to [Kerry] for building in some safety, but he may want to think about taking off or covering up that ring when working around high current sources. If you’re not quite so safety minded, this spot welder may or may not kill you.

Filed under: misc hacks, tool hacks

An Hour to Surface Mount

พุธ, 06/28/2017 - 03:00

Most of us have made the transition from through hole parts to surface mount. There are lots of scattered tutorials, but if you want to learn some techniques or compare your technique to someone else’s, you might enjoy [Moto Geek’s] hour-long video on how he does surface mount with reflow soldering. You can see the video below.

What makes the video interesting is that it is an hour long and covers the gamut from where to get cheap PCBs, to a homebrew pick and place pencil. [Moto Geek] uses a stencil with solder paste, and he provides links to the materials he uses.

Instead of a conventional squeegee, [Moto Geek] uses an old driver’s license which is a bit more flexible than a typical credit card. There are a few other tips and tricks you can garner from the video.

For the reflow oven, [Moto Geek] uses a modified toaster oven. However, you can get cheap reflow ovens that are made for that purpose. In the end, the results look good. This is one of those rare videos where you feel like you are in the shop looking over his shoulder while he builds his boards.

If you don’t have an oven, you can always try a blowtorch. If you’d rather 3D print your pick and place tool, we’ve seen it done before.

Filed under: tool hacks

Hackaday Prize Entry: A Tiva Shaped Like an Arduino

พุธ, 06/28/2017 - 01:30

Texas Instruments’ Tiva C LaunchPad showcases TI’s ARM Cortex-M4F, a 32-bit, 80Mhz microcontroller based on the TM4C123GH6PM. The Tiva series of LaunchPads serve as TI’s equivalent of the Arduino Uno, and hovers at about the same price point, except with more processing power and a sane geometry for the GPIO pins.

The Tiva’s processor runs five times faster than standard ATMega328P, and it sports 40 multipurpose GPIO pins and multiple serial ports. Just like the Arduino has shields, the Tiva has Booster Packs, and TI offers a decent number of options—but nothing like the Arduino’s ecosystem.

[Jacob]’s Arduino-Tiva project, an entry in the Hackaday Prize, aims to reformat the Tiva by building a TM4C123GH6PM-based board using the same form 2″x 3″ factor as the Arduino, allowing the use of all those shields. Of course, an Arduino shield only uses two rows of pins, so [Jacob]’s board would position the spare pins at the end of the board and the shield would seat on the expected ones.

The finished project could be flashed by either the Arduino IDE or TI’s Energia platform, making it an easy next step for those who’ve already mastered Arduinos but are looking for more power.

The HackadayPrize2017 is Sponsored by:
Filed under: The Hackaday Prize

A Crash Course in Thingiverse Customizer

พุธ, 06/28/2017 - 00:01

OpenSCAD is a great way to create objects for 3D printing (or other purposes), especially if you are already used to programming. For things like front panels, it is great because you can easily make modifications and — if you wrote your code correctly–everything will just adjust itself to new positions.

However, what if you have a general-purpose piece of code, and you want people to have the ability to customize it? For example, consider this code:

$fn=100; difference() { cube([25,25,5]); translate([4,4,-1]) cylinder(h=7,r=2); translate([25-4,4,-1]) cylinder(h=7,r=2); translate([4,25-4,-1]) cylinder(h=7,r=2); translate([25-4,25-4,-1]) cylinder(h=7,r=2); }

That creates the plate with four drill holes you see on the right.

Custom 101

It should be pretty obvious that you could use variables and if the end user had a copy of OpenSCAD, they could change things (click the link if you want to run OpenSCAD in your browser) without worrying about the math:

$fn=100; w=25;   // size of square thick=5;  // thickness drillhole_r=2;  // radius of drill hole drilloff=2;   // offset from edge of drill hole difference() { cube([w,w,thick]); translate([drilloff+drillhole_r,drilloff+drillhole_r,-1]) cylinder(h=thick+2,r=drillhole_r); translate([w-(drilloff+drillhole_r),drilloff+drillhole_r,-1]) cylinder(h=thick+2,r=drillhole_r); translate([drilloff+drillhole_r,w-(drilloff+drillhole_r),-1]) cylinder(h=thick+2,r=drillhole_r); translate([w-(drilloff+drillhole_r),w-(drilloff+drillhole_r),-1]) cylinder(h=thick+2,r=drillhole_r); }

You can easily change the variables at the top and get different size plates without having to manually readjust everything. If you are using the Web version, press F4 to see your changes. For a local copy, F5 would do the trick.

Not Good Enough

This isn’t good enough, though. Sure, people like us can fire up a copy of OpenSCAD and make changes to a program, but it might confuse some people. However, if you host your design on Thingiverse (and I’ll sidestep the political problems that always crop up) you have another option. Thingiverse offers a customizer option that allows you to build a simple GUI to change variables. It is really the same as the first case, but the application picks up simple comments to describe variables and other comments to set options. In addition, the variables have to be set by a constant.

In general, if you turn on Customizer, every variable that is set to a constant will show up in the GUI. I’ll show you how to avoid this in a bit, but for now, let’s just plug the simple example in and see how it does. Since there are no special comments, you get this:

This is actually not bad (Thingiverse login required). Each variable (even $fn) gets a text box where you can type in a different number. Underscores in the variable name turn into spaces and each one gets capitalized.  So even that simple setup is usable, especially if you pick nice variable names (which, perhaps, I didn’t).

It is easy to make this nicer, though. You can put a descriptive title on a comment just before the variable. For example:

// Width and height of plate (mm) w=25;

That will give you a more descriptive name. You can also put a comment right after the variable to get different effects. For example, this will give you a slider:

// Width and height of plate (mm) w=25; // [10:100]

Or you can provide a list of values:

// Bolt size (radius, mm) drillholl_r=2; // [2,4,8,10]

If you want a simple way to get rid of the $fn entry, you can just do this:


However, there are more advanced features available.


I won’t cover the methods you can use to upload an image or get a drawing canvas. You can check out the official documentation for that. However, The following code demonstrates a more substantial setup. The first comment defines a tab and you can use the tabs to organize sets of variables to make the GUI less confusing. In addition, you can define a [Hidden] tab to hide variables you don’t want to show. There’s also a [Global] tab that is always visible no matter what other tab is showing.

Otherwise, the example shows the basic text entry, sliders, and drop downs with a few extra features (for example, a step size on the slider). You can see the resulting objects to the left.

/* [Main Dimensions] */ // Outside diameter (mm) out_dia=50; // Height (mm) height=45; // Cut diameter (mm) cut_dia=30; /* [Inner Dimensions] */ // Inner diameter (mm) in_dia=21; // Depth (mm) in_depth=10; // [5,10,15,20,25] /* [Options] */ // Line segments for circles (3 for triangles, 6 for hex, etc.) FN=100; // [3:1:25] // Override line segement count (any positive value) OFN=0; $fn=OFN?OFN:FN; /* [Hidden] */ Num_copies=2; // Num_copies=1+0; // stop customizer from picking this up for (i=[1:Num_copies]) translate([(i-1)*out_dia*3,0,0]) difference() { union() { cylinder(center=false,r=out_dia/2, h=height); translate([-out_dia/2,-out_dia/2,height/2-height/8]) cube([out_dia,out_dia,height/4]); } translate([0,0,-1]) cylinder(center=false,r=cut_dia/2,h=1+height-in_depth); translate([0,0,,height-in_depth]) cylinder(center=false,r=in_dia/2,h=1+in_depth); } And Next Up…

We’ve always been surprised someone hasn’t come up with a standalone version of this that you could host on your own web site. The syntax is simple enough and we bet a few lines of Python and OpenSCAD would do the trick easily. That would let you host custom applications outside of Thingiverse and offer them for sale or let them send the completed files to a service bureau.

We find we rarely write any OpenSCAD anymore that we don’t enable for customizer. Almost anything is reusable if you do it right and sometimes the reuse opportunities can be surprising.

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

The Computer of Yesterday, Today

อังคาร, 06/27/2017 - 22:30

There are a handful of computers that have become true museum pieces. The Altair, of course, is tucked away in the Smithsonian’s warehouse waiting for some time in the future when Apple’s legacy fades or until there’s a remake of War Games. Likewise, the French Micral and American SCELBI are important historical artifacts, and even a modern component-accurate reproduction of an Apple I could fetch a decent amount of cash at the right auction.

There’s something special about these old kit computers – even though the instructions for these machines provided volumes of documentation, no one is building these machines anymore. You just can’t buy the PCBs, and sourcing period-correct components is hard. [Brad] is an exception. He found original, untouched PCBs for the cover story of the July, 1974 edition of Radio-Electronics. It’s an unbuilt Mark-8 minicomputer. Now [Brad] is in a position no one else has been in since the 1970s: he can build a vintage minicomputer, with a TV Typewriter, from scratch. He’s documenting the whole thing.

Since this is the first opportunity this century anyone has had to build a truly retro minicomputer, [Brad] is going all-in with this project. For an interface, he’s building [Don Lancaster]’s TV Typewriter, a device introduced in the September 1973 issue Radio-Electronics. When combined with an old CRT TV, the TV Typewriter becomes a serial terminal. While today something like this could be built around a single microcontroller, constructing the TV Typewriter is no small feat: it’s spread across four boards, uses character generator ROMs, and is currently housed in a beautiful red oak case.

Just because [Brad] is building an ancient computer using ancient parts doesn’t mean he can’t get a little help from modern technology. He’s applying white silk screen to his custom TV Typewriter boards using the toner transfer process. Yes, apparently you can get toner cartridges filled with white (and neon!) toner, and this works well enough to replicate the look of professionally silk screened boards.

This is one of the greatest retrocomputing projects we’ve seen in a very long time. This is a true retrocomputer, complete with custom transformers and gigantic linear power supplies. When this project is complete, [Brad] will have a museum piece, all thanks to a lucky find of an eBay auction and a lot of hard work.

Filed under: classic hacks

The PDP-1: The Machine that Started Hacker Culture

อังคาร, 06/27/2017 - 21:01

One of my bucket list destinations is the Computer History Museum in Mountain View, California — I know, I aim high. I’d be chagrined to realize that my life has spanned a fair fraction of the Information Age, but I think I’d get a kick out of seeing the old machines, some of which I’ve actually laid hands on. But the machines I’d most like to see are the ones that predate me, and the ones that contributed to the birth of the hacker culture in which I and a lot of Hackaday regulars came of age.

If you were to trace hacker culture back to its beginning, chances are pretty good that the machine you’d find at the root of it all is the Digital Equipment Corporation’s PDP-1. That’s a tall claim for a machine that was introduced in 1959 and only sold 53 units, compared to contemporary offerings from IBM that sold tens of thousands of units. And it’s true that the leading edge of the explosion of digital computing in the late 50s and early 60s was mainly occupied by “big iron” machines, and that mainframes did a lot to establish the foundations for all the advances that were to come.

At the time, computing was Very Serious Business Indeed. Big iron cost big bucks, and even a modest mainframe system was a huge capital investment for a company. So deep-pocketed customers dominated the market, and their needs shaped the hardware. More often than not, the primary need was to deal with big accounting problems, like running weekly payroll or quarterly profits. Computers of the day were primarily operated in batch mode, where stacks of punch card containing the programs and data were fed into the machine, outputting results hours or even days later. A computer operator was someone to move stacks of cards around and gather output, and the idea of sitting at a terminal was unthinkable. But DEC founder Ken Olsen had a different vision:

“We had a dream of interactive computing. Normal computing was considered big, expensive, awesome, beyond ordinary people. Interactive computing was exciting and fun, and people could interact directly with the computer.”

DEC was a very young company focused on selling its “Digital Laboratory Module” line of system building blocks to engineers, who more often than not used them to build test rigs for computers. Business was booming, and when Olsen laid out his vision to engineer Ben Gurley in 1959, the company had the resources to move quickly.

In just three and a half months Gurley and his team brought the Programmed Data Processor-1 to market, building it largely from DEC’s existing modules. The machine was smaller and cheaper than the mainframes of the day, and so it appealed to smaller companies and academia. In fact, the prototype was donated to MIT, where some of the more famous applications for it were developed. The video below shows the PDP-1 that the Computer Science Museum has lovingly restored running some of those, including Spacewar!, an surprisingly sophisticated game from which later classics like Asteroids clearly drew inspiration.

The bottom line is that the PDP-1 was really the first computer that encouraged users to sit down and play. While IBM machines did the boring but necessary work of business behind closed doors and tended by squads of servants, DEC’s machines found their way into labs and odd corners of institutions where curious folk sat in front of their terminals, fingers poised over keyboards while a simple but powerful phrase was uttered: “I wonder what happens if…” The DEC machines were the first computers that allowed the question, which is really at the heart of the hacker culture, to be answered in real time.

So if you happen to be in Mountain View some day, pay a visit to the PDP-1, the machine that started everything by making it okay to play.

[Featured image source: The Dot Eaters. Thumbnail source: Joi Ito via Wikimedia Commons]

Filed under: classic hacks, Featured, History

CastAR Shuts Doors

อังคาร, 06/27/2017 - 18:00

Polygon reports CastAR is no more.

CastAR is the brainchild of renaissance woman [Jeri Ellsworth], who was hired by Valve to work on what would eventually become SteamVR. Valve let [Jeri] go, but allowed her to take her invention with her. [Jeri] founded a new company, Technical Illusions, with [Rick Johnson] and over the past few years the CastAR has appeared everywhere from Maker Faires to venues better focused towards innovative technologies.

In 2013, Technical Illusions got its start with a hugely successful Kickstarter, netting just north of one million dollars. This success drew the attention of investors and eventually led to a funding round of $15 million. With this success, Technical Illusions decided to refund the backers of its Kickstarter.

We’ve taken a look a CastAR in the past, and it’s something you can only experience first-hand. Unlike the Oculus, Google Cardboard, or any of the other VR plays companies are coming out with, CastAR is an augmented reality system that puts computer-generated objects in a real, physical setting. Any comparison between CastAR and a VR system is incomplete; these are entirely different systems with entirely different use cases. Think of it as the ultimate table top game, or the coolest D&D game you could possibly imagine.

Filed under: news, slider, Virtual Reality

Tiniest Control Board Fits Inside an N-Gauge Model Train

อังคาร, 06/27/2017 - 15:00

[kodera2t] discovered the VL53L0X Time of Flight sensor and thought it would make a great way to control the operation of a model train without touching it.

The sensor was small enough for an N-gauge train, which translates to 1:148 scale or about 9mm from rail to rail. His idea was to build a tiny control board that could fit inside the locomotive: 10mm by 40mm. His board consists of the ToF sensor, an ATMega328P-MMH, USB-serial, and a Texas Instruments DRV8830 motor driver. he powers the board via the 6V running through the track.

Right now [kodera2t]’s using the ToF as sort of a gestural controller to get the train to start rolling, but one could imagine the sensor could be incorporated into more advanced programming, like having the train speed up on straightaways and slow down on a curve, based on the height of the bridge over it.

We’ve published a bunch of [kodera2t]’s tiny circuit board projects here on Hackaday, including the smallest basic computer, his minimal frequency counter, and his VFD amplifier.

Filed under: Arduino Hacks

Using Machine Learning To Cut Down Surgical Videos

อังคาร, 06/27/2017 - 12:00

Recording video of medical surgeries is a great way to both educate doctors in training and identify process improvements. However, surgeries can be very time consuming, and it can be a gargantuan task to sort through endless hours of video searching for relevant points where the action happens. To tackle this issue, researchers at MIT have used machine learning techniques to analyse videos of surgical procedures.

There’s some fairly serious mathematics behind this sort of videographic analysis.

The machine learning algorithm needed to be trained to identify the relevant parts of surgical videos. To do this, the laparoscopic surgeries being investigated were split up into distinct stages, each relating to a different part of the surgical process. Researchers would then watch recordings of prior surgeries and mark the start of each stage. This data was used to train the model which was then used to sift through other recordings to capture the key moments of each surgery.

The time-saving advantages of such technology could be applied to a great many fields – such an algorithm could be put to great use to sort through hours of uneventful security footage looking for anomalies, or rapidly cut together holiday footage so you only have to see the good parts. We’d love to see the researchers release footage showing the algorithm’s work – thus far, all we have to go off is the project paper.

If you’re thirsty for more machine learning knowledge, read up on the state of working with neural networks in 2017.

Filed under: Medical hacks

Simple Wave Generation in Python (and SciPy)

อังคาร, 06/27/2017 - 09:00

[153Armstrong] did a short post on how easy it is to generate waveforms using Python. We agree it is simple, but actually, it isn’t so much Python per se, it is some pretty cool libraries (SciPy, in particular) that do all the hard work. That may be splitting hairs, but it is worth nothing that SciPy (pronounced “Sigh Pie”) also does other handy tricks like Fourier transforms, too. You can see a video of his results, below.

The code is simple and one of the commenters pointed out an even more efficient way to write the data to a WAV file. The basic idea is to create an array of samples in a buffer using some features of SciPy’s NumPy component.

Most regular waveforms are easy to create using an algorithm. For example, sine waves can be generally described as: y=amplitude * sine(radian_frequency*t+phase_shift)

Where y is the value of the wave at time t. The amplitude is the peak value (so 5 will give you +/-5 V) and the radian frequency is twice the value of pi times the frequency in Hertz. [153Armstrong] shows simple formulae for sine waves, symmetric and asymmetric square waves, and a sawtooth wave, using generators provided by the SciPy package. The code is on GitHub and he also links to the generators available in SciPy.

We’ve seen SciPy in some Hackaday contest entries before. You can think of it like Matlab for Python. Just keep in mind, it isn’t an inherent part of Python. If you use another language, you could use a similar library to get the same effect. And if you’re doing this in hardware, you’ll probably want to use look-up tables, to keep things fast and simple.

Filed under: software hacks

Ambitious ATtiny85 Board Tests a Beginner’s Skills

อังคาร, 06/27/2017 - 06:00

[Chris O’Riley] has been playing around with Arduinos for around a year, and decided he wanted a breadboardable ATtiny85 in order to prototype using the actual controller that would be used in the final project. He wants to use it to interface with a Bosch BMP280 pressure sensor, but for now it stands alone.

It’s a simple board with the Tiny85, 3.3 V and 5 V regulators, a power LED, as well as the usual resistor sand caps. The double-sided PCB [Chris] milled himself — he’s an illustrator and photographer by day, so it’s no surprise the board turned out gorgeous. He designed the board in Illustrator after taking a stab at Eagle, then ran it through his CNC to mill the circuits using a .017 inch end mill as well as drilling the vias. He add solder paste using the tip of a knife, but after messing around with an iron, he ended up investing in a hot air rework station.

We love our Tiny85s here on Hackaday. Check out the ATtiny85 gaming console, the NTSC-generating ATTiny85, and making DIY I2C devices with the chip.

Filed under: ATtiny Hacks

Oscilloscope Mod for the Blues

อังคาร, 06/27/2017 - 03:00

Roughly 8% of males and 0.6% of females are red-green color blind, and yet many common oscilloscopes use yellow and green for the traces for their two-channel readouts. Since [Roberto Barrios] is afflicted by deuteranopia, a specific form of red-green colorblindness that makes differentiating between yellow and green hard, if not impossible, he got to work hacking his Agilent oscilloscope to make it more colorblind friendly.

Starting with a tip from [Mike] from the EEVblog forums, [Roberto Barrios] set out to rewire the LCD interface and swap the red and green signals. That way yellow will turn bluish (red component replaced by blue) and it could be seen as “very different now” from the green trace on the readouts. Sounds simple right? Well, slight issue: the 0.5 mm pitch of the connector. He did not want to design a PCB and wait a few weeks to receive it, so he decided on using 0.1 mm wires held together with Kapton tape to route each signal individually from one connector to the other. After an hour under the microscope, it was done. And boy, his work is impressive, go check it out.

Voila! It worked splendidly. Now [Roberto Barrios] can use his scope. And, the stock UI is mostly grey or white, so swapping the red and blue channels did not change much the appearance of the interface. Moreover, the switch had a small unintentional bonus, the loading screen is much cooler now with an edgy red sky. Further, [Roberto Barrios] “would not be [himself] if [he] could resist changing the CH1 button backlight LED to blue, to match the new trace color. So, no [he] couldn’t.”

This was a well done and very functional oscilloscope mod, but if you need more frivolity in your life, fear not: we’ve got your back with real-time Quake played on an oscilloscope.

Filed under: misc hacks