Building a hard drive scratch controller


If you’re reading this blog then chances are you have a dead hard drive hanging out somewhere in your house. Here’s a weekend project that will put it back into use. [Andreas] took on the popular project which combines a hard drive and optical mouse to build a scratch controller.

The gist of the build is that you use an optical mouse sensor to track the movement of the platter. But [Andreas] made things harder on himself by not using the USB capability of the mouse and mapping it in software for his needs. Instead he plucked the sensor from the mouse, reading it using an Arduino. After much trial and error with the best way to coat the underside of the platter to play nicely with the sensor he managed to get it up and running. The controller issues commands using the MIDI protocol, forming a strong foundation for future upgrades which could lead to a full-blown DJ console hack.

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Kinect full body scanner


Why let the TSA have all the fun when it comes to full body scanning? Not only can you get a digital model of yourself, but you can print it out to scale.

[Moheeb Zara] is still in development with a Kinect based full body scanner. But he took a bit of time to show off the first working prototype. The parts that went into the build were either cut on a bandsaw, laser cut, or 3D printed. The scanning part of the rig uses a free-standing vertical rail which allows the Kinect to move along the Z axis. The sled is held in place by gravity and moved up the rail using a winch with some steel cable looped over a pulley at the top.

The subject stands on a rotating platform which [Moheeb] designed and assembled. Beneath the platform you’ll find a laser cut hoop with teeth on the inside. A motor mounted in a 3D printed bracket uses these teeth to rotate the platform. He’s still got some work to do in order to automate the platform. For this demo he move each step in the scanning process using manual switches. Captured data is assembled into a virtual module using ReconstructMe.

The Kinect has been used as a 3D scanner like this before. But that time it was scanning salable goods rather than people.

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Draw your own vinyl beats


The Dyskograf lets you make music with a magic marker. The musical installation looks much like a turntable for playing vinyl records. But instead of a spiraling groove containing the sounds, this uses marks on a paper disk to play sound samples.

You can see the light outline of several tracks on the paper disc shown above. By adding black marks the optical input of the Dyskograf knows when to start and end each sound. This is best illustrated in the video demonstration after the break.

The marker-based setup makes a lot of sense, and we think it would be perfect if the disc was a dry-erase board. It certainly makes it a lot easier to lay down new beats than this other optical turntable which required holes to be drilled in a vinyl record to play the sounds. While we’re on the topic you may also find this coin-based turntable sequencer of interest.

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Exercise bike actuates your download speeds; messes with music playback

We’re not featuring this project because it involves the tiniest exercise bike in the world. It’s on the front page because the speed-control features which this dynamic duo added are hilarious. They call it the Webcycle and it’s actually two hacks in one.

Way back in 2009 [Matt Gray] and [Tom Scott] slapped an Arduino on the bike and used it to measure the revolutions of the cranks (how fast your feet are going in circles). This was hooked up to the laptop which is fastened to the handlebars. This way you can surf the Internet while you work out, but the bandwidth is directly affected by pedal speed. If you want to watch video you’re going to have to sweat…. a lot. Check it out in the clip after the break.

This March they pulled the Webcycle out of storage so that it may ride again. This time it’s connected to the sound system in their exercise room. A record player motor is the victim in this case. You guessed it — pedal speed dictates the rate of the turntable, modulating the pitch drastically. Make sure the boss isn’t around when you watch this clip because it will be hard not to guffaw.

These guys really have fun with this hacks. It was [Tom’s] birthday that prompted that hacktacular mini golf course.

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Scanning turntable digitizes objects as 3D models

This turntable can automatically digitize objects for use in 3D rendering software like Blender3D. [James Dalby] built it using a high-quality DSLR, and some bits and pieces out of his junk box. The turntable itself is a Lazy Susan turned on its head. The base for the spinning model is normally what sits on the table, but this way it gives him an area to rest the model, and the larger portion acts as a mounting surface for the drive mechanism.

He used the stepper motor from a scanner, as well as the belt and tension hardware from a printer to motorize the platform. This is driven by a transistor array (a ULN2003 chip) connected to an Arduino. The microcontroller also controls the shutter of the camera. We’ve included his code after the break; you’ll find his demo video embedded there as well.

The concept is the same as other turntable builds we’ve seen, But [James] takes the post-processing one step further. Rather than just make a rotating gif he is using Autodesk 123D to create a digital model from the set of images.

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Automated turntable photography

[Muris] has a friend who is selling items on the internet. This friend wanted a simple way to make rotating images of the products and asked him to help. The result of his labors is this base unit that drives the turn table and controls the camera.

The first iteration of the turntable was powered by the stepper motor from a floppy drive. A disc was mounted directly on the motor spindle, but the results were a bit poor. This is because the motor had a fairly low resolution of 200 steps per rotation. That doesn’t allow for smooth animation, and there was a lot of vibration in the system. An upgrade to the geared system you see above included swapping out that motor for one from an old scanner. Now it achieves 1200 steps per rotation and the vibration is gone.

The connectors seen in the base are USB, incoming power, and shutter control. [Muris] wrote a program to control the PIC 16F628A inside the base. The program sends commands via USB and has parameters for number of frames per rotation, direction of rotation, and the like. Set it up as desired, place the product on the turntable, and hit start. Unfortunately there’s no video of this in action because [Muris] gave it to his friend as soon as it was finished. We guess the fact that he didn’t get it back means it’s working great.

If you don’t mind some rough edges and exposed wiring you can throw a system of your own together pretty quickly.

Rotating platform makes most useless machine concept useful

[Valentin] used a simple concept to build this auto-reversing rotating platform. The concept is extremely simple, the leads for the motor are attached to a double-pole double-throw switch which allow the polarity to be reversed. Flip the switch in one direction and it spins clockwise. Flip it in the other direction and it spins counter-clockwise.

In this case, he’s harnesses the power of the most useless machine. That often seen hack uses a similar switch, but accomplishes nothing by having the moving parts act as the actuator. This one is useful, taking advantage of a single or double arm to flip the switch and make the platform spin backwards. In the video after the break you can see it’s used to create a scanning security camera. But [Valentin] also shows it at work as a turntable for salable goods. We think’s the gearing is a little brisk for both purposes, but slowing it down is a hack for another day. Continue reading “Rotating platform makes most useless machine concept useful”