Year: 2017

Stunning Fake Polaroid Camera Performs Magic

August 31, 2017 by 39 Comments

It’s high time us Muggles got our hands on the hardware used to take Magical Photographs as seen in The Daily Prophet. The first pioneering step in that direction has been taken by [Abhishek] who built this moving picture taking polaroid-ish camera, which he’s calling the “Instagif NextStep”. It’s a camera that records a short, three second video, converts it to GIF and ejects a little cartridge which displays the animated photo.

This amazing piece of hardware has been painstakingly built, and the finished product looks great. The nice thing about building such projects, in [Abhishek]’s own words, is that “it involves a bunch of different skill sets and disciplines – hardware, software, 3D modeling, 3D printing, circuit design, mechanical/electrical engineering, design, fabrication etc that need to be integrated for it to work seamlessly.”
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Way To Go, Einstein; His Time Spent Being Wrong

August 31, 2017 by 116 Comments

When you hear someone say “Einstein”, what’s the first thing that pops into your head? Is it high IQ… genius… or maybe E=MC2? Do you picture his wild grey hair shooting in all directions as he peacefully folds the pages back from his favorite book?  You might even think of nuclear bombs, clocks and the Nobel Prize. It will come as a surprise to many that these accomplishments were a very small part of his life. Indeed, Einstein turned the world of classical physics upside down with his general theory of relativity. But he was only in his early twenties when he did so.

What about the rest of his life? Was Einstein a “one-hit-wonder”? What else did he put his remarkable mind to? Surely he tackled other dilemmas that plagued the scientific world during his moment in history. He was a genius after all… arguably one of the smartest people to have ever walked the earth. His very name has become synonymous with genius. He pulled the rug out from under Isaac Newton, whose theories had held the universe together for over 300 years. He talked about enigmatic concepts like space and time with an elegance that laid bare the beauty hidden within their simplicity. Statues have been made of him. His name and face are recognizable across the globe.

But when you hear someone say “Einstein”, do you think of a man who spent the better half of his life… being wrong?  You should.

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Can You Visualise A Sega Cart From 2017?

August 31, 2017 by 13 Comments

The Sega Genesis, or Mega Drive if you’re not from North America, isn’t exactly this summer’s hottest new console, but it still has a huge following 29 years after launch. Fans range from retro Sonic enthusiasts to hardcore chiptune composers, and this year, Catskull Electronics is releasing a Genesis compilation album on a cartridge with a rather special feature.

The cartridge sports an 8×8 LED matrix, which acts as a visualiser for the audio coming out of the console. They’re controlled with a combination of data and address lines with some buffers and 74-series glue logic to make it all work together. Special attention was paid to make sure the LED matrix doesn’t just respond to all activity on the bus, though it would perhaps be cool to see some blinkenlights on a 90s console one day.

Each row of LEDs is attached to an address line, and each column to a data line. It’s a fairly basic multiplexing setup which sees each LED only actually lit for a fraction of a second, but sweeping the display at speed creates a lasting display. The image data is stored as an 8×8 sprite in the system RAM, and updated with the sound level of each channel from the Genesis’s audio subsystem.

The team are looking to release the ROM code in future to inspire copycat designs, which has the potential to spawn even more Genesis cart releases in future. We look forward to seeing what else the community comes up with. And if you’re a die-hard Genesis fan, there are other ways to listen to those classic tunes too.

Repurposing Moving Coil Meters To Monitor Server Performance

August 31, 2017 by 11 Comments

Snazzy analog meters can lend a retro flair to almost any project, but these days they often seem to be retasked as indicators for completely different purposes than originally intended. That’s true for these Vu meters repurposed as gauges for a Raspberry Pi server, and we think the build log is as informative as the finished product is good-looking.

As [MrWunderbar] admits, the dancing needles of moving-coil meters lend hipster cred to a project, but getting his Vu meters to cooperate and display network utilization and disk I/O on his Raspberry Pi NAS server was no mean feat. His build log is full of nice details on how to measure the internal resistance of the meter and determine a proper series resistor. He also has a lengthy discussion of the relative merits of driving the meters using a PWM signal or using a DAC; in the end, [MrWunderbar] chose to go the DAC route, and the video below shows the desired rapid but smooth swings as disk and network usage change. He also goes into great depth on pulling usage parameters from psutil and parsing the results for display on the meters.

Looking for more analog meter goodness? We saw a similar CPU load meter a few months back, and there was this mash-up of Nixies and old meters for a solar energy CEO’s desk.

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A Very Accurate Current Probe

August 30, 2017 by 13 Comments

There’s many different ways of measuring current. If it’s DC, the easiest way is to use a shunt resistor and measure the voltage across it, and for AC you could use a current transformer. But the advent of the Hall-effect sensor has provided us a much better way of measuring currents. Hall sensors offers several advantages over shunts and CT’s – accuracy, linearity, low temperature drift, wider frequency bandwidth, and low insertion loss (burden) being some of them. On the flip side, they usually require a (dual) power supply, an amplification circuit, and the ability to be “zero adjusted” to null output voltage offsets.

[Daniel Mendes] needed to measure some fairly high currents, and borrowed a clip-on style AC-DC current probe to do some initial measurements for his project. Such clip on current probes are usually lower in accuracy and require output DC offset adjustments. To overcome these limitations, he then built himself an invasive hall sensor current probe to obtain better measurement accuracy (Google Translated from Portugese). His device can measure current up to 50 A with a bandwidth stretching from DC to 200 kHz. The heart of his probe is the LAH-50P hall effect current transducer from LEM – which specialises in just such devices. The 25 mV/A signal from the transducer is buffered by an OPA188 op-amp which provides a low output impedance to allow interfacing it with an oscilloscope. The op-amp also adds a x2 gain to provide an output of 50 mV/A. The other critical part of the circuit are the high tolerance shunt resistors connected across the output of the LAH-50P transducer.

The rest of his design is what appears to be a pretty convoluted power supply section. [Daniel] wanted to power his current probe with a 5V input derived from the USB socket on his oscilloscope. This required the use of a 5 V to 24 V boost switching regulator – with two modules being used in parallel to provide the desired output power. A pair of linear regulators then drop down this voltage to +15 / -15 V required for the trasducer and op-amp. His blog post does not have the board layout, but the pictures of the PCB should be enough for someone wanting to build their own version of this current sensor.

Detecting Dire Diseases – With A Selfie?

August 30, 2017 by 27 Comments

They say the eyes are the windows to the soul. But with a new smartphone app, the eyes may be a diagnostic window into the body that might be used to prevent a horrible disease — pancreatic cancer. A research team at the University of Washington led by [Alex Mariakakis] recently described what they call “BiliScreen,” a smartphone app to detect pancreatic disease by imaging a patient’s eyes.

Pancreatic cancer is particularly deadly because it remains asymptomatic until it’s too late. One early symptom is jaundice, a yellow-green discoloration of the skin and the whites of the eyes as the blood pigment bilirubin accumulates in the body. By the time enough bilirubin accumulates to be visible to the naked eye, things have generally progressed to the inoperable stage. BiliScreen captures images of the eyes and uses image analysis techniques to detect jaundice long before anyone would notice. To control lighting conditions, a 3D-printed mask similar to Google’s Cardboard can be used; there’s also a pair of glasses that look like something from [Sir Elton John]’s collection that can be used to correct for ambient lighting. Results look promising so far, with BiliScreen correctly identifying elevated bilirubin levels 90% of the time, as compared to later blood tests. Their research paper has all the details (PDF link).

Tools like BiliScreen could really make a difference in the early diagnosis and prevention of diseases. For an even less intrusive way to intervene in disease processes early, we might also be able to use WiFi to passively detect Parkinson’s.

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Ultrasonic Array Gets Range Data Fast And Cheap

August 30, 2017 by 8 Comments

How’s your parallel parking? It’s a scenario that many drivers dread to the point of avoidance. But this 360° ultrasonic sensor will put even the most skilled driver to shame, at least those who pilot tiny remote-controlled cars.

Watch the video below a few times and you’ll see that within the limits of the test system, [Dimitris Platis]’ “SonicDisc” sensor does a pretty good job of nailing the parallel parking problem, a driving skill so rare that car companies have spent millions developing vehicles that do it for you. The essential task is good spatial relations, and that’s where SonicDisc comes in. A circular array of eight HC-SR04 ultrasonic sensors hitched to an ATmega328P, the SonicDisc takes advantage of interrupts to make reading the eight sensors as fast as possible. The array can take a complete set of readings every 10 milliseconds, which is fast enough to allow for averaging successive readings to filter out some of the noise that gets returned. Talking to the car’s microcontroller over I2C, the sensor provides a wealth of ranging data that lets the car quickly complete a parallel parking maneuver. And as a bonus, SonicDisc is both open source and cheap to build — about $10 a copy.

Rather use light to get your range data? There are some pretty cheap LIDAR units on the market these days.

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