A Homemade Bubble Robot for the Kids


Kids generally can be amused pretty easily, but when jangling keys stop holding their interest you might want to take a look at [drenehtsral]‘s new project. He’s created an automatic bubble robot (YouTube link) that keeps the kids endlessly entertained!

The project started as an idea at a festival where one of [drenehtsral]‘s kids took great interest at a bubble machine. [drenehtsral] had never heard of a bubble machine before, but it turns out that it’s pretty simple in practice. All that’s required is a tank of soapy water, a motor to turn the bubble wands, and a fan to form the bubbles and make them waft gently through the air.

[drenehtsral] also used a 12V battery for power, some other hardware to hold it all together, and a 5V regulator and some other control electronics for the fan and the motor. He notes that he could have bought a bubble machine but in true hacker style found it fun to build himself. The next step in this project could be something to vary the size of the bubbles, or perhaps a set of wheels for the robot so it can entertain the kids on the move!

[Read more...]

A Beverage Cooler with a Stereo


If you are looking for a way to spice up your summertime parties, try following [Pastryboy's] lead. After letting the idea rattle around in his head for a few years, he finally built himself the cooler he always dreamed of.

[Pastryboy] was originally inspired by a YouTube video he found a few years ago. He took the basic concept and rolled with it. He started out with a mini fridge he found for $10. He removed the compressor and other plumbing bits. He also removed all of the internal shelving. Any leftover holes were patched up with silicone. Now when the fridge is laid on its back, it’s essentially the same as an ordinary cooler.

Next [Pastryboy] purchased two 6.5″ Boss speakers and an inexpensive head unit. He drilled a few pilot holes in the side of the refrigerator and then used a jigsaw to cut the holes to the proper sizes. Once the speakers were mounted in place, he needed to find a way to waterproof the inside. This was accomplished by using some small plastic bowls. The edges of the bowls were attached to the cooler wall using silicone.

[Pastryboy] was able to run most of the cabling through the inside of the cooler’s walls. The system is powered by a 12V lead acid battery. He chose a specific model of battery that can be stored in any orientation and that can handle being knocked around a little bit.

Next he added a couple of handles to the sides to make it easier to transport. A small bit of ski rope was attached to the inside of the lid, preventing the lid from flopping completely open. [Pastryboy] also added a drain to the bottom to make it easier for one person to empty the cooler. The final touch was to pretty it up a bit. He sanded down the entire thing and gave it several coats of red paint. The end result looks very slick.

[via Reddit]

The Science of Strengthening Glass

Strengthen Glass

[Ben Krasnow] is at it again. This time he’s explaining a simple method for strengthening glass. As usual, he does a fantastic job of first demonstrating and explaining the problem and then following it up with a solution.

[Ben] first uses a simple rig to place a controlled amount of force against a glass microscope slide. His experiment shows that the slide shatters once about 30psi of force has been applied to the center of the slide.

[Ben] then goes on to explain that current methods for producing glass leave many tiny impurities, or cracks, in the glass. As the glass slide flexes, the inside edge is placed into a compression force while the outside edge is under tension. The glass is more easily able to handle the compression force. The tension is where things start to break down. The tension force eventually causes those tiny impurities to spread, resulting in the shattering glass.

One possible solution to this problem is to find a way to fill in those tiny impurities. According to [Ben], most glass has sodium added to it in order to lower the melting temperature. [Ben] explains that if you could replace some of these smaller sodium atoms with larger atoms, you could essentially “fill” many of the tiny impurities in the glass.

[Ben] does this himself by heating up a small vat of potassium nitrate. Once the powder becomes molten, he submerges the glass slides in the solution for several hours. During this time, some of the sodium atoms are replaced by potassium atoms due to the natural process of diffusion.

Once the slides have cooled down, [Ben] demonstrates that they become much stronger. When placed in the testing rig, the stronger slides do not break until the pressure gets between 60psi and 70psi. That’s twice as strong as the original glass. All that extra strength from such a simple process. Be sure to watch the full video below. [Read more...]

Pole Climbing Device Runs Up Flags and Undies

Tubular Drive travels up and down poles

Driving a carriage up and down a cylindrical object isn’t the most popular activity but that is certainly no reason not to build such a device. Check out [Ryan's] creation that does just that, he calls it a Tubular Drive.

There isn’t much going on here, basically there are 4 wheels that grip a pipe. Two of those wheels have integrated gears and are driven by a DC motor. The remaining two wheels are idlers. When power is applied to the motor, two of the wheels spin, which then moves the entire assembly down the pole. A quick reversal in polarity brings the unit back the other way.

With those 3D printed plastic wheels you may think that traction would be an issue but [Ryan] insists that it is not a problem. The ABS wheels were treated with an acetone bath to smooth out the print layers and the distance between the wheels can be adjusted using a couple of bolts. Together that allows enough surface contact and pressure to ensure slip-free traveling.

Although the wheels were made to grip 1/2″ electrical conduit, it would be very easy to adapt this design to fit around and climb up all sorts of cylindrical objects, maybe even rope! Perhaps v-wheels with a spring tensioner system would allow for traveling on different size tubes while also adjusting for any variation in the diameter of a single tube.

[Ryan] says version two will have a linear encoder and be driven by a stepper motor. Check out the video after the break…

[Read more...]

Building A Home Made iPhone

iThing A few years ago, [Michele] built a mobile device with a touch screen, a relatively powerful processor, and a whole bunch of sensors. To be honest, the question of why he built this was never asked because it’s an impressive display of electronic design and fabrication. [Michele] calles it the iGruppio. Although it’s not a feature-packed cell phone, it’s still an impressive project that stands on its own merits.

Inside the iGruppio is a Pic32mx microcontroller, a 240×320 TFT touchscreen, and enough sensors to implement a 10 DOF IMU. The software written for the iGruppio is heavily inspired by the iPhone and a completely homebrew project – all the software was written by [Michele] himself. While the first version of the iGruppio was a little clunky, the second revision (seen in the pic above) uses an old iPhone case to turn a bunch of boards and plugs into a surprisingly compact device.

No, there’s no cellular modem inside the latest version, but [Michele] has put all the sources up on Github, and anyone wanting to build a homebrew cell phone could do worse than to take a look at his work. Video demo below.

[Read more...]

Focus Your Ears with The Visual Microphone


A Group of MIT, Microsoft, and Adobe researchers have managed to reproduce sound using video alone. The sounds we make bounce off every object in the room, causing microscopic vibrations.  The Visual Microphone utilizes a high-speed video camera and some clever signal processing to extract an audio signal from these vibrations. Using video of everyday objects such as snack bags, plants, Styrofoam cups, and water, the team was able to reproduce tones, music and speech. Capturing audio from light isn’t exactly new. Laser microphones have been around for years. The difference here is the fact that the visual microphone is a completely passive device. No laser or special illumination is required.

The secret is in the signal processing, which the team explains in their SIGGRAPH paper (pdf link). They used a complex steerable pyramid along with wavelet filters to obtain local pixel motion values. These local values are averaged into a global motion value. From this global motion value the team is able to measure movement down to 1/1000 of a pixel. Plenty of resolution to decode audio data.

Most of the research is performed with high-speed video cameras, which are well outside the budget of the average hacker. Don’t despair though, the team did prove out that the same magic can be performed with consumer cameras, albeit with lower quality results. The team took advantage of the rolling shutter found in most of today’s CMOS imager based consumer cameras. Rolling shutter CMOS sensors capture images one row at a time. Each row can be processed in a similar fashion to the frames of the high-speed camera. There are some inter-frame gaps when the camera isn’t recording anything though. Even with the reduced resolution, it’s easy to pick out “Mary had a little lamb” in the video below.

We’re blown away by this research, and we’re sure certain organizations will be looking into it for their own use. Don’t pull out your tin foil hats yet though. Foil containers proved to be one of the best sound reflectors.

[Read more...]

DIY USB Spectrometer Actually Works

image of diy spectrometer

When we hear spectrometer, we usually think of some piece of high-end test equipment sitting in a CSI lab. Sure, a hacker could make one if he or she put their mind to it. But make one out of a webcam, some cheap diffraction grating purchased off ebay and some scrap? Surely not.

[Renaud] pulls off this MacGyver like build with a detailed knowledge of how spectrometers work. A diffraction grating is used to split the incoming light into its component wavelengths. Much like a prism would. The wavelengths then make their way through a slit, which [Renaud] made from two pieces of highly polished brass, so the webcam sensor can see a specific wavelength. While the spectrometer-from-webcam concept isn’t new,  the build is still impressive.

Once the build was complete, [Renaud] put together some software to make sense of the data. Though a bit short on details, we hope this build will inspire you to make your own spectrometer, and document it on hackaday.io of course.


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