Year: 2020

Schlieren On A Stick

August 25, 2020 by 10 Comments

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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An Old Calculator Lives Again

August 24, 2020 by 42 Comments

There was a time when any electronics student would have a slide rule hanging off their belt. By the 1970s, the slide rule changed over to an electronic calculator which was a pricy item. Today you can buy calculators at the dollar store. [JohnAudioTech] pulled out an old Radio Shack vacuum fluorescent display (VFD) calculator and found it didn’t work. Obviously, that means it is time to open it up.

It is fun to see one of these old devices opened up again. Consumer electronics with big through-hole ICs! Troubleshooting the device wound up being anti-climatic, as a broken wire to the battery compartment explained the whole thing.

As a teardown, though, this is a fun video. Not only are all the parts through-hole, but the PCB is clearly a manual layout with serpentine traces flowing across the board like some sort of art piece. Continue reading “An Old Calculator Lives Again” →

Hacking D-Link Firmware

August 24, 2020 by 15 Comments

When [0xRickSanchez] found some D-Link firmware he couldn’t unpack, he was curious to find out why. The firmware had a new encryption method which was doing its job of preventing tampering and static analysis. Of course, he had to figure out how to get around it and is documenting his work in a series of blog posts.

Looking at the entropy analysis showed the data to be totally random,  a good sign it was either encrypted or compressed. The target router cost about $200, but a similar cheaper router used the same encryption and thus this model became the hardware of choice for testing.

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Reactive Pixel Lamps Create Colourful Vibes On Command

August 24, 2020 by 3 Comments

Phillips Ambilight technology is a curious thing, never quite catching on in the mainstream due to its proprietary nature. Consisting of an LED array that sits behind a television screen, it projects colours relevant to the content on screen to create a greater feeling of ambience. [Ed Chamberlain]’s reactive pixel lamps aim to do much the same thing in a more distributed way.

Each pixel lamp consists of a Wemos D1 controller fitted with an old-school 4-wire RGB LED. The components are placed in a 3D printed translucent cube, which serves as an attractive enclosure and diffuser. With WiFi connectivity on board, it’s possible to connect the individual cubes up to a Raspberry Pi serving as a Phillips Hue bridge thanks to DIYHue. Once setup, the lights can be configured as an Ambilight system within the Phillips Hue app.

It’s an impressive way to give a room reactive lighting on a budget, without resorting to costly off-the-shelf solutions. We’d love to see this expanded further, as we’re sure a room full of reactive lights would be truly a sight to behold. Other methods to recreate the Ambilight technology are possible, too. Video after the break.

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Arduino Rig Does Spectrophotometry

August 24, 2020 by 13 Comments

Spectrophotometry is an important scientific tool, most commonly used in biology and chemistry. It’s a method to measure the amount of light absorbed by a chemical solution at various different wavelengths. While it’s typically the preserve of expensive lab equipment, [Daniel Hingston] built a rig to do the job at home.

The heart of the rig is a normal filament-based flashlight bulb, which produces good-quality white light containing all colors. A prism is then used to split the light into its component wavelengths, so that the sample can be tested across the whole light spectrum. The prism is rotated by a servo motor, which exposes the sample to the full rainbow, while an Arduino uses a light-dependent resistor to measure how much light makes it through the sample. Thus, the amount of light absorbed by the sample can be calculated, relative to calibrations made with no sample present.

It’s a simple build that can be achieved with fairly common materials, barring the prism which may need to be specially ordered. It would be a great way to teach highschool students about advanced scientific concepts, as well as showing them behind the curtain of how lab equipment works.

We see all kinds of DIY science gear around here; this lantern-based bioreactor is a great example. Video after the break.

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Assistive Gloves Come In Pairs

August 24, 2020 by 11 Comments

We have to hand it to this team, their entry for the 2020 Hackaday Prize is a classic pincer maneuver. A team from [The University of Auckland] in New Zealand and [New Dexterity] is designing a couple of gloves for both rehabilitation and human augmentation. One style is a human-powered prosthetic for someone who has lost mobility in their hand. The other form uses soft robotics and Bluetooth control to move the thumb, fingers, and an extra thumb (!).

The human-powered exoskeleton places the user’s hand inside a cabled glove. When they are in place, they arch their shoulders and tighten an artificial tendon across their back, which pulls their hand close. To pull the fingers evenly, there is a differential box which ensures pressure goes where it is needed, naturally. Once they’ve gripped firmly, the cables stay locked, and they can relax their shoulders. Another big stretch and the cords relax.

In the soft-robotic model, a glove is covered in inflatable bladders. One set spreads the fingers, a vital physical therapy movement. Another bladder acts as a second thumb for keeping objects centered in the palm. A cable system draws the fingers closed like the previous glove, but to lock them they evacuate air from the bladders, so jamming layers retain their shape, like food in a vacuum bag.

We are excited to see what other handy inventions appear in this year’s Hackaday Prize, like the thumbMouse, or how about more assistive tech that uses hoverboards to help move people?

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Running A Successful Hacker Camp In A Pandemic: BornHack 2020

August 24, 2020 by 10 Comments

You could say 2020 is The Year That Didn’t Happen, or perhaps even The Year That Everything Happened Online. All the international cons and camps have been cancelled, and we’ve spent our time instead seeing our friends in Jitsi, or Zoom.

But there was one camp that wasn’t cancelled. The yearly Danish hacker camp BornHack has gone ahead this year with significantly reduced numbers and amid social distancing, turning it from what is normally one of the smaller and more intimate events into the only real-world event of 2020.

I bought my ticket early in the year and long before COVID-19 became a global pandemic, so on a sunny day in August I found myself in my car with my friend Dani from FizzPop hackerspace in Birmingham taking the ferry for the long drive through the Netherlands and Germany to Denmark.

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