On the left side, there's a smartphone. On the right side, there's a hairdryer turned on. On the smartphone screen, you can see the working end of the hairdryer shown, as well as a jet of air coming out of that end. In the background, there's an LCD screen showing a noise pattern.

Observe Airflow Using Smartphone And Background-Oriented Schlieren

Multiple people have recently shared this exciting demonstration (nitter) with us – visualizing airflow using a smartphone, called ‘background-oriented schlieren’. On a hot summer day, you might see waves in the air – caused by air changing density as it warms up, and therefore refracting the light differently. Schlieren photography is an general set of techniques for visualizing fluid flow, but of course, it can also be applied to airflow. In this case, using some clever optical recognition tricks, this schlieren method lets you visualize flow of air using only your Android smartphone’s high resolution camera and a known-pattern printed background! Continue reading “Observe Airflow Using Smartphone And Background-Oriented Schlieren”

Helicopter Is Full Of Compressed Air

[Tom] likes to build little helicopters and decided to build one that runs on compressed air. (Video, embedded below.) Turns out it was a little harder than he thought. Originally, he was trying for a compressed air quadcopter. He’d already worked with an air turbine, but putting on a vehicle that can lift itself into the air turns out to have a lot of hidden gotchas.

[Tom] went through a lot of design considerations to arrive at the helicopter design. He considered counter-rotating props, but there were a host of problems involved. He finally settled on a single prob with a tail rotor that resides on the far end of a long boom to allow the resulting lever arm to reduce the work required of the tail rotor.

Continue reading “Helicopter Is Full Of Compressed Air”

Hacklet 90: Schlieren Videos And Jigsaw Puzzle Robots

Happy new year, and welcome to the first Hacklet of 2016! The Hacklet is one of my favorite columns to write, as I get to talk about the great projects people are working on at Hackaday.io. Generally these articles follow a theme, but this being a new year, I’m going to try something new. As Hackaday’s community editor, I keep an eye on the new and updated projects feeds over on Hackaday.io. Every single week I see projects that surprise, impress, and inspire me. This week, I’m going to highlight a couple that I think are just freaking awesome.

torch[Jana Marie] created the Schlieren-Videography project. Schlieren photography is used to image changing densities in fluids and this includes capturing density changes in air. Super and Hypersonic wind tunnels often use this technique to show airflow around a test model. Outside of the wind tunnel, Schlieren is great for showing density changes due to heat or different gasses. That’s exactly what [Jana] is doing in this project.

There are several ways to create Schlieren images, everything from lasers, to diffraction gratings, to razor blades can be used. [Jana] is using a simple moiré pattern and a couple of video tricks to capture Schlieren video. A high density moiré pattern will appear to flicker as density changes bend the light from the moiré stripes. [Jana] simply takes a reference image, then subtracts that image from the live video. The result of the subtraction is the Schlieren images you see above. [Jana] did more than explain the technique she’s used to create the videos, she’s also uploaded a processing sketch which performs the video subtraction magic.

jigsolve[Dan Royer] has a more domestic problem – his family loves starting jigsaw puzzles, but never seems to finish them. He’s decided to invite around 3 billion of his closest friends in the form of JigSolve, an internet connected jigsaw puzzle robot. JigSolve’s Cartesian platform  is a CoreXY based design. [Dan] used CoreXY as a guideline, but designed and built the hardware himself. The electronic hardware side borrows from RepRap 3D printers. An Arduino Mega2560 and RAMPS board control two NEMA 17 stepper motors. The Arduino is running firmware from Makelangelo, [Dan’s] own open source art robot.

The internet connected portion of the project comes in the form of a Java based IRC bot and a connection to the Freenode IRC network. The internet connected masses will have to see what they are working on, so a Logitech webcam will stream video to the ‘net.

The hardest part of JigSolve thus far has been the nozzle. Much like an SMT pick and place machine, the nozzle needs to pick up parts with a vacuum, then rotate them to the desired orientation. [Dan] is looking at different kinds of silicon, and he’s asking for suggestions. Stop over on the project page and offer him a hand!

That’s it for this week’s Hacklet. As always, see you next week. Same hack time, same hack channel, bringing you the best of Hackaday.io!