Making 3D Print Time-lapses With Old Earphones And A Few Spare Parts

The trick to producing great 3D printing time-lapse animations is to ensure that the extruder has moved out of the frame each time a photo is taken — which usually requires OctoPrint to be controlling both the camera and printer. But [NirL] managed to bodge up a system to get the same result with a spare limit switch, a resistor, his mobile phone, and an old set of earbuds. Not bad for some spare parts and a little extra G-Code.

The print head hits a remote shutter button during a brief parking action after each layer.

Inserting custom G-Code to park the print head at regular intervals takes care of standardizing the printer’s movements; there’s even a post-processing extension in Cura that makes this easy. As for triggering the camera, [NirL] was inspired by the remote shutter button on a selfie stick. By positioning a physical switch in such a way that the print head pushes it every time it (briefly) parks, a photo gets taken for every layer. Essentially the same thing Octolapse does, just with fewer parts.

To create the DIY remote shutter button, [NirL] used a spare limit switch, resistor, and cannibalized an old set of earbuds for the cable and 4-conductor 3.5 mm audio plug. Most phones and camera apps trigger the shutter when they receive a Vol+ signal through the audio plug, which is done by connecting MIC and GND through a 240 Ohm resistor.

In this way a photo is snapped for every layer, giving [NirL] all that is needed to assemble a smooth animation. Sure, it ties up a mobile phone for the duration of the print, but for just a few spare parts it does the job. You can see the project in action in the video, embedded just under the page break.

As mentioned, the usual way to implement effortless time-lapses is by using the Octolapse plugin for OctoPrint, which creates silky smooth animations without the typical blur of time-lapses.

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Schlieren On A Stick

Schlieren imaging is a technique for viewing the density of transparent fluids using a camera and some clever optical setups. Density of a fluid like air might change based on the composition of the air itself with various gasses, or it may vary as a result of a sound or pressure wave. It might sound like you would need a complicated and/or expensive setup in order to view such things, but with a few common things you can have your own Schlieren setup as [elad] demonstrates.

His setup relies on a cell phone, attached to a selfie stick, with a spherical mirror at the other end. The selfie stick makes adjusting the distance from the camera to the mirror easy, as a specific distance from the camera is required as a function of focal length. For cell phone cameras, it’s best to find this distance through experimentation using a small LED as the point source. Once it’s calibrated and working, a circular field of view is displayed on the phone which allows the viewer to see any change in density in front of the mirror.

The only downside of this build that [elad] notes is that the selfie stick isn’t stiff enough to prevent the image from shaking around a little bit, but all things considered this is an excellent project that shows a neat and useful trick in the photography/instrumentation world that could be useful for a lot of other projects. We’ve only seen Schlieren imaging once before and it used a slightly different method of viewing the changing densities.

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