3D Printed Fish Feeder

[Helios Labs] recently published version two of their 3D printed fish feeder. The system is designed to feed their fish twice a day. The design consists of nine separate STL files and can be mounted to a planter hanging above a fish tank in an aquaponics system. It probably wouldn’t take much to modify the design to work with a regular fish tank, though.

The system is very simple. The unit is primarily a box, or hopper, that holds the fish food. Towards the bottom is a 3D printed auger. The auger is super glued to the gear of a servo. The 9g servo is small and comes with internal limiters that only allow it to rotate about 180 degrees. The servo must be opened up and the limiters must be removed in order to enable a full 360 degree rotation. The servo is controlled by an Arduino, which can be mounted directly to the 3D printed case. The auger is designed in such a way as to prevent the fish food from accidentally entering the electronics compartment.

You might think that this project would use a real-time clock chip, or possibly interface with a computer to keep the time. Instead, the code simply feeds the fish one time as soon as it’s plugged in. Then it uses the “delay” function in order to wait a set period of time before feeding the fish a second time. In the example code this is set to 28,800,000 milliseconds, or eight hours. After feeding the fish a second time, the delay function is called again in order to wait until the original starting time.

Dead Simple Hologram Effect

We’ve all seen holograms in movies, and occasionally we see various versions of the effect in real life. The idea of having a fully three-dimensional image projected magically into space is appealing, but we haven’t quite mastered it yet. [Steven] hasn’t let that stop him, though. He’s built himself a very simple device to display a sort of hologram.

His display relies on reflections. The core of the unit is a normal flat screen LCD monitor laid on its back. The other component looks like a four-sided pyramid with the top cut off. The pyramid is made from clear plastic transparency sheets, held together with scotch tape. It’s placed on top of the LCD with the narrow end facing down.

[Steven] then used the open source Blender program to design a few 3D animations. Examples include a pterodactyl flying and an approximation of the classic Princess Leia hologram from Star Wars Episode 4. The LCD screen displays the animation from four different angles at once. The images are displayed up and onto the transparency sheet, which then get reflected to your eyes. The result is an image that looks almost as if it’s floating in space if viewed from the proper angle. If you move around the screen you can see the image from all four sides, which helps to sell the effect. Not bad for a few dollars worth of parts. Continue reading “Dead Simple Hologram Effect”

Hackaday Links: December 21, 2014

Most of the incredible flight simulator enthusiasts with 737 cockpits in their garage are from the US. What happens when they’re from Slovenia? They built an A320 cockpit. The majority of the build comes from an old Cyprus Airways aircraft, with most of the work being wiring up the switches, lights, and figuring out how to display the simulated world out of the cockpit.

Google Cardboard is the $4 answer to the Oculus Rift – a cardboard box and smartphone you strap to your head. [Frooxius] missed being able to interact with objects in these 3D virtual worlds, so he came up with this thing. He adapted a symbol tracking library for AR, and is now able to hold an object in his hands while looking at a virtual object in 3D.

Heat your house with candles! Yes, it’s the latest Indiegogo campaign that can be debunked with 7th grade math. This “igloo for candles” will heat a room up by 2 or 3 degrees, or a little bit less than a person with an average metabolism will.

Last week, we saw a post that gave the Samsung NX300 the ability to lock the pictures taken by the camera with public key cryptography. [g3gg0] wrote in to tell us he did the same thing with a Canon EOS camera.

The guys at Flite Test put up a video that should be handy for RC enthusiasts and BattleBot contenders alike. They’re tricking out transmitters, putting push buttons where toggle switches should go, on/off switches where pots should go, and generally making a transmitter more useful. It’s also a useful repair guide.

[Frank Zhao] made a mineral oil aquarium and put a computer in it. i7, GTX 970, 16GB RAM, and a 480GB SSD. It’s a little bigger than most of the other aquarium computers we’ve seen thanks to the microATX mobo, and of course there are NeoPixels and a bubbly treasure chest.

WirePrint is a Physical ‘Print Preview’ for 3D Printers

3D printers may be old news to most of us, but that’s not stopping creative individuals from finding new ways to improve on the technology. Your average consumer budget 3D printer uses an extrusion technology, whereby plastic is melted and extruded onto a platform. The printer draws a single two-dimensional image of the print and then moves up layer by layer. It’s an effective and inexpensive method for turning a computer design into a physical object. Unfortunately, it’s also very slow.

That’s why Hasso Plattner Institute and Cornell University teamed up to develop WirePrint. WirePrint can slice your three-dimensional model into a wire frame version that is capable of being printed on an extrusion printer. You won’t end up with a strong final product, but WirePrint will help you get a feel for the overall size and shape of your print. The best part is it will do it in a fraction of the time it would take to print the actual object.

This is a similar idea to reducing the amount of fill that your print has, only WirePrint takes it a step further. The software tells your printer to extrude plastic in vertical lines, then pauses for just enough time for it to cool and harden in that vertical position. The result is much cleaner than if this same wire frame model were printed layer by layer. It also requires less overall movement of the print head and is therefore faster.

The best part about this project is that it’s a software hack. This means that it can likely be used on any 3D printers that use extrusion technology. Check out a video of the process below to see how it works. Continue reading “WirePrint is a Physical ‘Print Preview’ for 3D Printers”

The Race Is On To Build A Raspi Kinect 3D Scanner

pinect

The old gen 1 Kinect has seen a fair bit of use in the field of making 3D scans out of real world scenes. Now that Xbox 360 Kinects are winding up at yard sales and your local Goodwill, you might even have a chance to pick one up for pocket change. Until now, though, scanning objects in 3D has only been practical in a studio or workshop setting; for a mobile, portable scanner, you’d need to lug around a computer, a power supply, and it’s not really something you can fit in a back pack.

Now, finally, that may be changing. [xxorde] can now get depth data from a Kinect sensor with a Raspberry Pi. And with just about every other ARM board out there as well. It’s a kernel driver that’s small, fast, and does just one thing: turns the Kinect into a webcam that displays depth data.

Of course, a portabalized Kinect 3D scanner has been done before, but that was with an absurdly expensive Gumstix board. With a Raspi or BeagleBone Black, this driver has the beginnings of a very cheap 3D scanner that would be much more useful than the current commercial or DIY desktop scanners.

Copying objects in 3D

photocopier

[Pulse 9] sent in a very interesting project he just finished up at an internship. It’s a 3D photocopier that scans an object and then mills said object into floral foam.

The copier is made out of material [Pulse] found sitting around – PVC, drawer slides for the X and Y axes, acrylic for the structure, and broken printer parts for the Z axis.

To scan an object, [Pulse] puts an object down on the bed and scans it with a laser and webcam. The images recorded on the camera are fed into MATLAB. The output from MATLAB is sent over serial to a custom board containing a PIC18F4620 that controls the axis motors. The spindle for this floral foam router is a simple drill; one layer at a time, the drill mills out the unneeded foam which can be sucked up by a vacuum when the object is complete.

Below you’ll find [Pulse]’s demo of his photocopier and a piece the local news did on the project. If anyone is willing to translate that story, feel free to do so in the comments.

Continue reading “Copying objects in 3D”

TightLight: A 3D projection mapping assistant

tightLight

Anyone can grab a projector, plug it in, and fire a movie at the wall. If, however, you want to add some depth to your work–both metaphorical and physical–you’d better start projection mapping. Intricate surfaces like these slabs of styrofoam are excellent candidates for a stunning display, but not without introducing additional complexity to your setup. [Grady] hopes to alleviate some tedium with the TightLight (Warning: “music”).

The video shows the entire mapping process of which the Arduino plays a specific role toward the end. Before tackling any projector calibration, [Grady] needs an accurate 3D model of the projection surface, and boy does it look complicated. Good thing he has a NextEngine 3D laser scanner, which you’ll see lighting the surface red as it cruises along.

Enter the TightLight: essentially 20 CdS photocells hooked up to a Duemilanove, each of which is placed at a previously-marked point on the 3D surface. A quick calibration scan scrolls light from the projector across the X then Y axis, hitting each sensor to determine its exact position. [Grady] then merges the photocell location data with the earlier 3D model using the TouchDesigner platform, and bam: everything lines up and plays nice.