Hackaday links: September 7, 2012

MakerSlide, European edition

We’re all familiar with the MakerSlide, right? The linear bearing system that has been turned into everything from motorized camera mounts to 3D printers is apparently very hard to source in Europe. A few folks from the ShapeOko forum have teamed up to produce the MakerSlide in the UK. They’re running a crowdsourced project on Ulule, and the prices for the rewards seem very reasonable; €65/£73 for enough extrusion, v-wheels, and spacers to make an awesome CNC router.

Kerf bending and math

A few days ago, I made an offhand remark asking for an engineering analysis of kerf bending. [Patrick Fenner] of the Liverpool hackerspace DoES already had a blog post covering this, and goes over the theory, equations, and practical examples of bending acrylic with a laser cutter. Thanks for finding this [Adrian].

276 hours well spent

[Dave Langkamp] got his hands on a Makerbot Replicator, one thing led to another, and now he has a 1/6 scale model electric car made nearly entirely out of 3D printed parts. No, the batteries don’t hold a charge, and the motor doesn’t have any metal in it, but we’ve got to admire the dedication that went in to this project.

It was thiiiiiiis big

If you’ve ever tried to demonstrate the size of an object with a photograph, you’ve probably placed a coin of other standard object in the frame. Here’s something a little more useful created by [Phil]. His International Object Sizing Tool is the size of a credit card, has inch and cm markings, as well as pictures of a US quarter, a British pound coin, and a one Euro coin. If you want to print one-off for yourself, here’s the PDF.

Want some documentation on your TV tuner SDR?

The full documentation for the E4000/RTL2832U chipset found in those USB TV tuner dongles is up on reddit. Even though these chips are now out of production (if you haven’t bought a proper tuner dongle yet, you might want to…), maybe a someone looking to replicate this really cool device will find it useful.

Visualizing heat with Schlieren photography

[Kevin] wanted to check out the air patterns present when his 3D printer is in action. This is useful research; slight differences in temperature can affect the quality of his prints. Instead of something like a thermometer, [Kevin] decided to use Schlieren photography to visualize the air around his 3D printer.

If you’ve ever seen very old-school pictures of supersonic research, you’ve seen Schlieren photography. It’s a way of visualizing the density of transparent objects using only mirrors, lenses, and a point light source. The resulting pictures are usually black and white, although some amazing color pictures exist of bullets traveling through the air next to soap bubbles and candles.

The process of creating a Schlieren photograph is actually pretty easy. [Kevin] pointed a light at a used a 4-inch parabolic mirror placed behind his printer. A knife edge is placed at exactly twice the focal length of the mirror, and after putting a camera behind this knife edge, differences in the density of the air are visible.

From [Kevin]’s video of his Schlieren setup (available after the break), you can see the air is extremely turbulent around his print. That might have been obvious given the presence of a cooling fan, but it’s still very, very cool to look at.

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Stop Motion Animation Creation

PVC man stop motion animation

Stop Motion Animation has always been interesting to me since I “discovered” that one could make animated flip books by drawing each frame a little different. Fast forward 20 years or so, and computer technology has gotten to the point where this sort of thing can be done electronically quite easily and at an incredibly low price of a camera, computer, and free or paid-for software (here’s the technique using GIMP, a free, good quality photo editing tool) to put everything together.

The frames in the picture above are of my latest [PVC man] animation, which can be made with some electroluminescent lights, gloves, and some PVC pipe.  Each frame was individually photographed, and after several hours of work we had enough footage for 17 seconds of so of stop-motion animation.

Although by no means perfect, the quality of these animations has gone up dramatically from the first animations that I made using an old ENV2 camera phone. Although I was using a “custom mount” for it, it’s amazing these came out as well as they did. As with everything hacking related, this process is a constant work in progress. Check out the videos after the break for the [PVC man] video as well as one of the early ENV2-produced stop-motion shorts!

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Take a picture of a bang with a camera sound trigger

We’ve featured dozens of digital camera triggers over the years. Very rarely do we come across one as well designed as [Viktor]’s ‘lil bang sound trigger that snaps a picture whenever a microphone picks up a loud noise.

[Viktor]’s build is based around a PIC16F microcontroller with an LM386 amp connected to a microphone. On the front of the device, the right knob controls the sensitivity of the microphone and the left knob sets the delay between detection and the trigger.

The ‘lil bang trigger connects to the camera through an opto-isolated 3.5 mm jack that is compatible with all the fancy Canon and Nikon DSLRs. The delay between sound detection can be changed from 0 to 255 ms, allowing for precise control over a high-speed photography rig.

All this work comes after the  light-activated trigger [Viktor] built for taking pictures of lightning. The sound-activated version wouldn’t work for lightning pics, but he thinks it could be useful for collision or explosion photographic studies. Check out the video of [Viktor]’s ‘lil Bang in action after the break.

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Rainbow Machine livens up any photograph


[Shameel Arafin, Sean McIntyre, and Reid Bingham] really dig rainbows. Going by the moniker the “RainBroz”, the trio built a portable display that can be used to add cool light painting effects to pictures.

The group brings their Rainbow Machine all over the place, including parties, gatherings, and random spots on the street. Anyone is welcome to have their picture taken with the Rainbow machine, and each subject is given a card with a URL on it, so that they can check out their picture whenever they please.

The display consists of addressable RGB LED strips and an Arduino from Adafruit, along with the associated support mechanisms for moving the LEDs. The real magic is carried out by the LPD8806 light painting library, also from Adafruit, which enables the RainBroz to create all sorts of images with little fuss.

As you can see in the video below, the Rainbow Machine seems to get a pretty warm reception from just about everyone, even people grabbed right off the street. It looks simple enough to build, so why not put one together for your next gathering?

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Hackaday Links: December 7, 2011

LED Neurons

[Alexandra Olivier] put up an art installation at Wellesley College that looks like a bunch of neurons built out of LEDs. The neurons are connected to a couple PIR sensors and ‘fire’ whenever movement is detected. The result is a lot like being inside a brain. Fitting, then, that the installation is called Social Synapses.

Last year’s big toy was always evil, though

Last year, [Andrew] had to fight the throngs of shoppers to get the must have toy of the season, a Zhu Zhu pet. Since these robotic hamster things have spent the last 11 months in the back of a closet, it seems reasonable to make them evil. They’re still not as evil as a demonic Furby….

So we call it a bifocal, right?

There’s an old photography trick for a really hacky macro setup – just turn the lens around. Well, what if you wanted automatic metering and flash control? Simple, just electrically reverse the lens. Bonus points for being able to use the lens regularly as well.

Control all the bands

Well here’s something cool: an all-in-one USB 315mhz, 433mhz, and 868mhz transceiver. What can you do with it? Well, [codeninja] can control the outdoor lights for two of his neighbors, open gates and doors, crash his weather station, and just about anything else in those bands. It’s pretty much like war driving for important stuff nobody cares about.

So this is our favorite holiday now

There’s a Dutch tradition to play Sinterklaas and make someone a present. [Jenor] decided to build an antique-looking DC voltmeter with a pair of vacuum tubes. The tubes don’t work anymore, but the heaters still provide a nice warm glow. It’s a bit large to be regularly used as a piece of test equipment, but it really does look awesome. Very steampunkey, and it’s the though that counts anyway.

The Picture Post – Observe Your World in Extreme Slow Motion

The “Picture Post”, a tool for a program going on through the University of New Hampshire, is a method of taking what amounts to extreme time-lapse photography. The purpose of this project is to observe the world around you with a 360 degree view taken at a regular interval.

The setup is quite simple consisting of a 9 inch diameter post, and an octagon to set your camera against.  Just place your camera one edge, take the picture and repeat around the octagon until done. You can register on their site to make your post official and contribute to society’s general knowledge about the environment and seasonal changes.

Although interesting in itself, this concept could be applied to many situations that one would want to record in this manner.  For instance, a “hacker post” could be set up in a hackerspace for members to record their projects on or even the progress of the building itself.  For another much less developed way to take photos, check out this trigger device using air freshener parts!

via [Make Magazine]