When Detecting Lines Is Harder Than Expected

April 22, 2018 by Donald Papp 18 Comments

[Conor Patrick] is no stranger to hardware development, and he’s had an interesting project for the past few months. He’s attempting to create a tool to convert images of technical drawings (such as footprints for electronic components) into digital formats that can be imported into other tools. This could automate turning a typical footprint drawing like the one shown into an actual part definition in a CAD program, which could really speed up the creation of custom parts.

Key to the entire concept is the detection of lines in a black-and-white technical drawing. To some people this won’t sound like a particularly challenging problem; choose one or another baked-in line detection function, maybe with a bit of pre or post-processing, and that should be that. It turns out that detecting lines can be harder than expected, and as usual the devil is in the detail.

When [Conor] tried some existing methods for detecting lines, the results appeared good at first but came up short in frustrating ways. Software did not appreciate that in a technical drawing, a line is a single unbroken unit from point A to point B. Without that assumption, what should be a single line sometimes had sections missing, or single lines were detected as multiple segments instead of a unit. Lines that crossed other lines complicated things. Unwanted lines like a “1” or the lower half of a “Y” were being detected. There had to be a better way.

In the end, a custom solution that took proper advantage of the nature of the source images and made the correct assumptions is what made all the difference. With some intelligent threshold setting combined with looking at vertical and horizontal line instances separately, it was possible to locate lines and their lengths far more accurately than any other method he had tried. The system doesn’t handle sloped lines yet, but it might be possible to simply iterate through rotations of the image while applying the same method. If you have a better solution, [Conor] wants to hear from you.

Of course, garbage in means garbage out and sadly not all technical drawings measure up.

GuerillaClock Could Save This City Thousands

April 22, 2018 by Bryan Cockfield 32 Comments

They say necessity is the mother of invention. But if the thing you need has already been invented but is extremely expensive, another mother of invention might be budget overruns. That was the case when [klinstifen]’s local government decided to put in countdown clocks at bus stops, at a whopping $25,000 per clock. Thinking that was a little extreme, he decided to build his own with a much smaller price tag.

The project uses a Raspberry Pi Zero W as its core, and a 16×32 RGB LED matrix for a display. Some of the work is done already, since the bus system has an API that is readily available for use. The Pi receives the information about bus schedules through this API and, based on its location, is able to determine the next bus arrival time and display it on the LED matrix. With the custom 3D printed enclosure and all of the other material, the cost of each clock is only $100, more than two orders of magnitude less expensive.

Hopefully the local government takes a hint from [klinstifen] and decides to use a more sane solution. In the meantime, you might be able to build your own mass transit clock that you can use inside your own house, rather than at the train station, if you’re someone who has a hard time getting to the bus stop on time.

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Blueprints Make It Easy To Make (Some) Alexa Skills

April 22, 2018 by Al Williams 13 Comments

If you can code, you can create an Alexa skill — the programs that allow an Amazon Echo or similar device interact with you. What if you can’t code or you are just too lazy to do all the setup? Amazon now has Blueprints that can help anyone make a skill. The only problem is the skills you can create are pretty limited. In addition, they are only available to your Alexa devices.

The idea is simple. You start with a template — OK, a blueprint. This is a model application that does something like giving you a compliment or a joke on demand. When you open the blueprint, you’ll see a list of things it can say. You can edit the list, including adding or deleting things. Then you name the new skill. In a few minutes, your skill will be live on your devices.

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Computers May Someday Need A Drink

April 21, 2018 by Brian McEvoy 16 Comments

“We want to put water right into your processor.” If that statement makes you sweat, that is good. Sweating is what we’re talking about, but it’s more involved than adding some water like a potted plant. Sweating works naturally by allowing liquid to evaporate, and that phase change is endothermic which is why it feels cool. Evaporative coolers that work in this way, also known as swamp coolers, haven’t been put into computers before because they are full of sloshy water. Researchers in South Korea and the United States of America have been working on an evaporative cooling system mimicking the way some insects keep themselves cool by breathing through their exoskeletons while living in damp soil.

Springtails are little bugs that have to keep the water and air separate, so they don’t drown in the wet dirt where they live. Mother Nature’s solution was for them to evolve to do this with columns that have sharp edges at the exit. Imagine you slowly add water to a test tube, it won’t spill as soon as you reach the top, it will form a dome. This is the meniscus. At a large scale, say a river dam, as soon as you get over the dam you would expect spillage, but at the test tube level you can see a curve. At the scale of the springtail, exuded water will form a globe and resist water pressure. That resistance to water pressure allows this type of water cooling to self-regulate. Those globes provide a lot of surface area, and as they evaporate, they allow more water to replenish the globe. Of course, excessive pressure will turn them into the smallest squirt guns.

We have invented a lot by copying Mother Nature. Velcro was inspired by burrs, and some of our most clever robots copy insects. We can also be jerks about it.

3D Drone Video

April 21, 2018 by Al Williams 10 Comments

If you enjoy flying quadcopters, it is a good bet that you’ll have a drone with a camera. It used to be enough to record a video for later viewing, but these days you really want to see a live stream. The really cool setups have goggles so you can feel like you are actually in the cockpit. [Andi2345] decided to go one step further and build a drone that streams 3D video. You can see a video of the system, below.

Outdoors, there’s probably not a lot of advantage to having a 3D view, but it ought to be great for a small indoor drone. The problem is, of course, a small drone doesn’t have a lot of capacity for two cameras. The final product uses two cameras kept in sync with a sync separator IC and a microcontroller, while an analog switch intersperses the frames.

On the viewing side, a USB frame grabber and a Raspberry Pi splits the images again. At first, the system used an LCD screen married with a Google Cardboard-style goggle, but eventually, this became a custom Android application.

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Got A Burning Idea For An EMF Camp Presentation? Now’s Your Chance!

April 21, 2018 by Jenny List 8 Comments

Sometimes the world of tech conference presentations can seem impossibly opaque, a place in which there appears to be an untouchable upper echelon of the same speakers who pop up at conference after conference. Mere mortals can never aspire to join them and are destined to forever lurk in the shadows, their killer talk undelivered.

Thankfully, our community is not like that. There is a rich tradition of events having open calls for participation, and the latest we’d like to bring to your attention comes from the British EMF Camp, to be held at the end of August. EMF, (standing for ElectroMagnetic Field) is a 3-day festival that bills itself as “for those with an inquisitive mind or an interest in making things“. In their call for participation, they are seeking installations and performances as well as talks and workshops, and it’s worth saying given the very quick uptake of their early ticket sales, that a couple of tickets will be reserved for purchase by each person with proposals that are accepted.

EMF Camp like other hacker camps is an extraordinary coming together of people from all conceivable backgrounds and interest groups to share a field for three days. It doesn’t matter how experienced you are, what the subject is that you would like to present, or what installation or workshop you would like to bring, there will be a section of the EMF audience who would be very interested to see it. They list a few previous topics, from genetic modification to electronics, blacksmithing to high-energy physics, reverse engineering to lock picking, computer security to crocheting, and quadcopters to brewing. Assuming that certain submissions are accepted, you may also see a Hackaday scribe delivering a talk.

While you’re thinking of what to submit for 2018, whet your appetite with a look at the goings-on from EMF 2016.

Image: Nottingham Hackspace [CC BY-SA 2.0].

Roomba-Riding Beer Butlers Will Serve Us All

April 21, 2018 by Kristina Panos 7 Comments

[Josh] isn’t one to refuse a challenge, especially when robots are involved. The latest dare from friends and family? Build a beer robot that can bring beverages at everyone’s beck and call.

The build consists of two main parts: the refrigerated cooler and the butler part, which comes courtesy of a Roomba Discovery from a fellow roboticist. [Josh] is basing the design on double-walled and insulated restaurant coolers. He built the refrigerated beverage hold from two stainless steel trash cans, sized an inch or so apart in diameter, and filled the gap with expanding foam insulation. He then cut away several inches from the bottom of the liner can to make room for the cooling unit, reinstalled the drip tray, and made a [airflow-allowing platform] by drilling a bunch of holes in an antimicrobial plastic cutting board.

At first, he tried a Peltier unit from an electric Igloo cooler, but that doesn’t work as well as [Josh] hoped, so he’s redesigning the can to use a mini fridge compressor. This meant making custom evaporator and condenser coils from copper tubing to match the compressor’s load spec. Go through [Josh]’s build logs over on IO and you’ll get a free mini-course on expanding foam and refrigeration.

[Josh] is currently working on some different butler modes for this robot. These run the gamut from simply sitting nearby with cold beverages and opening with the wave of a hand to doing voice-triggered beverage butler-ing at everyone’s beck and call. We applaud his efforts thus far and will be following this one with great ~~thirst~~ interest to see how he handles navigation and voice control.