3D Printing With 2D Inkscape Projections

August 2, 2015 by 7 Comments

If you had a formal drafting class, you probably learned about making orthographic projections–engineering drawings with multiple views (for example, top, front, and right). Even if you didn’t take the class, you’ve probably seen drawings like this where you view a 3D object as a series of 2D views from different angles.

These days, you are more likely to create a 3D model of an object, especially if you are going to 3D print it. After all, the 3D printer software is going to expect a model. When [Nightshade] wanted a laptop stand for his workbench, he started trying to do a 3D model. His final product though, was made by creating two views in Inkscape. They aren’t exactly orthographic projections of the final product, but the idea is similar.

Inkscape is a vector graphics program and generally creates SVG files, although it can also save EPS files. [Nightshade] used pstoedit to convert the EPS output to DXF format. DXF files are still two dimensional, but OpenSCAD can extrude DXF files into 3D shapes.

Just having a 3D shape of one view isn’t sufficient, though. The OpenSCAD script rotates the objects to the correct orientation and intersects them to form the final object. This is different from the usual cases of using Inkscape to trace a scan or generate simple text.

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Downloading Satellite Images Via FM Radio

August 2, 2015 by 63 Comments

Did you know weather satellites transmit their weather images over an FM frequency? And now that you know… You can intercept them yourself with a $10 FM radio dongle!

American NOAA weather satellites are in a polar orbit around earth, and each one will pass the same point approximately every 12 hours. When it is overhead, the signal is strong enough to receive. After [Matt] found out this tidbit of knowledge, he had to learn how to intercept the images himself.

The satellites transmit the images over the 137MHz band, and using a radio tuner USB dongle, you can record the transmission and then decode it into a picture. He used CubicSDR to tune and record the signal, and then Soundflower to pull out interference, and finally WXtoIMG — which starts recording when the satellite is above, and decodes the image.

[Thanks for the tip Amirgon!]

Shinewave Gamecube Controller Reacts To Smash Brothers

August 2, 2015 by 8 Comments

[Garrett Greenwood] plays Smash Brothers, and apparently quite seriously. So seriously that he needed to modify his controller with five Neopixels so that it flashed different color animations according to the combo he’s playing on the controller; tailored to match the colors of the moves of his favorite character, naturally.

All of this happens with an ATtiny85 as the brains, which we find quite ambitious. Indeed, [Garrett] started out thinking he could simply read each of the inputs from the controller directly into the microcontroller at the heart of the whole thing, but then counted up how many wires that would be, and looked at how many pins he had free (six), and thought up a better solution.

[Garrett]’s routine instead reads the single line that the Gamecube controller uses to send back to the console. The protocol is well understood, using long-short and short-long signals to encode bits. The only trick is that each bit is sent in four microseconds, so the decoding routine has to be fairly speedy. To make it work he had to do quite a bit of work. More about that, and the demo video, after the break.

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Homemade High Voltage Caps

August 2, 2015 by 12 Comments

Do you happen to have any 15,000 volt capacitors sitting around? [Ludic Science] didn’t so he did the next best thing. He built some.

If you understand the physics behind a capacitor (two parallel conductors separated by a dielectric) you won’t find the build process very surprising. [Ludic] uses transparency film as an insulator and aluminum foil for the conductive plates. Then he wraps them into a tube. He did throw in a few interesting tips about keeping the sheets smooth and how to attach the wires to the foil. The brown paper wrapper reminded us of old caps you might find in an antique radio.

The best part by far, though, was the demonstration of drawing an arc from a high voltage power supply with and without the capacitor in the circuit. As you might expect, playing with a few thousand volts charged into a capacitor requires a certain amount of caution, so be careful!

[Ludic] measured the capacitance value with a standard meter, but it wasn’t clear where the 15,000 volt rating came from. Maybe it was the power supply he used in the video and the capacitor could actually go higher.

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I Am A Battery: Harvesting Heat Energy

August 2, 2015 by 17 Comments

If you get tired of charging batteries, you might be interested in [Hackarobot’s] energy harvesting demo. He uses a peltier device (although he’s really using it as a thermocouple which it is). A 1 farad super capacitor stores energy and an LTC3108 ultra low voltage converter with a 1:100 ratio transformer handles the conversion to a useful voltage.

The truth is, the amount of energy harvested is probably pretty small–he didn’t really characterize it other than to light an LED. In addition, we wondered if a proper thermocouple would work better (some old Russian radios used thermocouples either in fireplaces or kerosene lamps to avoid requiring batteries). Although a Peltier device and a thermocouple both use the Seebeck effect, they are optimized for different purposes. Thermocouples generate voltage from a temperature differential and Peltier modules generate temperature differentials from voltage.

However, as [Hackarobot] points out, the same technique might be useful with other alternate power sources like solar cells or other small generators. The module used has selectable output voltages ranging from 2.35V to 5V.

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Hackaday Prize Entry: Real Time Power Monitoring

August 1, 2015 by 19 Comments

The Internet of Things promises real-time monitoring of appliances, HVAC, and just about everything else in the home. One of the biggest technologies behind this is the smart meter, an electrical meter that will tell you how much power you’re sucking down from the grid at any given moment. A meter need not be smart, though, because [jlbrian7]’s entry for the Hackaday Prize does the same thing without an entirely new meter.

[jlbrian]’s power monitor is a non-intrusive monitor for electrical systems, allowing anyone to retrofit an electrical meter – or just a single breaker panel – with smart meter tech. It uses a small current transformer to monitor the amperage running through a wire. By sending that information to the Internet, anyone with this system gets power monitoring with much higher temporal resolution than what the power company provides in a monthly bill.

As a nice little addition to his Power Monitor, [jlbrian] is adding a few environmental sensors to his data logging platform. This allows for a little bit of interpolation to figure out what all that power is actually being used for; if the power turns on and a few minutes later the temperature drops, there’s a pretty good chance the AC just went on.

The 2015 Hackaday Prize is sponsored by:

It Sucks To Pick Up The Pieces

August 1, 2015 by 11 Comments

Jigsaw puzzles are a fun and interactive way to spend an afternoon or twelve, depending on the piece count and your skill level. It’s exciting to find the pieces you need to complete a section or link two areas together, but if you have poor dexterity, excitement can turn to frustration when you move to pick them up. [thomasgruwez] had the disabled and otherwise fumble-fingered in mind when he created this pick and place jigsaw puzzle aid, which uses suction to pick up and transport puzzle pieces.

The suction comes from an aquarium pump running in reverse, a hack we’ve seen often which [thomasgruwez] explains in a separate Instructable. A large, inviting push button is wired in line to turn the pump on and off. An equally large and inviting momentary switch turns off the vacuum temporarily so the piece can be placed.

At the business end of this hack is the tiny suction-cupped tip from a cheap vacuum pen. To interface the pen head with the pump, [thomasgruwez] designed and printed a rigid straw to bridge the gap. With utility already in mind, [thomasgruwez] also designed a ring that can be bolted to the straw to house a steadying finger of your choice, like the pinkie hook on a pair of barbers’ shears.

Our favorite part of this hack has to be the optional accessory—a tiny platform for quickly flipping pieces without cutting the vacuum. Check it out after the break.

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