Air Quality Sensors In Every Classroom

June 18, 2016 by Bryan Cockfield 4 Comments

One of the first electronics projects for the aspiring hobbyist is wiring a sensor of some sort to a microcontroller, and then doing something useful with the new information. [Brock] has taken this type of gateway project and turned it into a way to get his students involved and familiar with electronics. His take on an air quality meter accomplishes both of these goals, and hopefully helps turn all of his students into the next generation of hackers.

The bill of materials is pretty straightforward. Instead of the go-to Arduino, [Brock] has gone with a Particle Photon which has the added benefits of various wireless connectivity options. The air quality sensor is a Shinyei PP42ns which interfaces easily with the Photon. The only thing that might be out of reach of most public high schools (at least in the United States) is the 3D-printed enclosure, although if you have access to one, [Brock] put the files on the project page so anyone can use them.

Of course, we’re big fans of projects that get students involved in anything beyond standardized tests, and this project goes a long way towards teaching students more than how to pass a test. There are many videos and instructions on the project page if you want to try this on your own, but if the cost for the materials is the only thing scaring you off from doing this in your own classroom there are a few other options. You could use ATtiny chips, or try a different style of sensor, or maybe just try out a different project altogether.

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Single Photon Source For Quantum Computing And Experimentation

May 7, 2016 by Al Williams 28 Comments

One challenge to building optical computing devices and some quantum computers is finding a source of single photons. There are a lot of different techniques, but many of them aren’t very practical, requiring lots of space and cryogenic cooling. Recently, researchers at the Hebrew University of Jerusalem developed a scalable photon source on a semiconductor die.

Using nanocrystals of semiconductor material, the new technique emits single photons, and in a predictable direction. The nanocrystals combine with circular nanoantennas made of metal and dielectric produced with conventional fabrication technology. The nanoantennas are concentric circles resembling a bullseye and is used to ensure that the photons travel the correct direction with little or no angular deviation.

A single IC could contain many photon sources and they operate at room temperature. We’ve talked about quantum tricks with photons before. Quantum mechanics is another popular topic.

Fixing Broken Monitors By Shining A Flashlight

January 22, 2016 by Brian Benchoff 67 Comments

[dyril] over on the EEVblog has a broken LED TV. It’s a fairly standard Samsung TV from 2012 that unfortunately had a little bit of corrosion on the flexible circuit boards thanks to excessive humidity. One day, [dyril] turned on his TV and found about one-third of the screen was glitchy. After [dyril] took the TV apart, an extremely strange fix was found: shining a light on the corroded flexible circuit board fixed the TV.

The fix, obviously, was to solder a USB light to a power rail on the TV and hot glue the light so it shines on the offending circuit. Solving a problem is one thing, though, understanding why you’ve solved the problem is another thing entirely. [dyril] has no idea why this fix works, and it’s doubtful anyone can give him a complete explanation.

The TV is fixed, and although you can’t argue with results, there is a burning question: how on Earth does shining a light on a broken circuit board fix a TV? Speculation on the EEVblog thread seems to have settled on something similar to the photonic reset of the Raspberry Pi 2. In the Raspberry Pi 2, a small chip scale package (CSP) used in the power supply section would fail when exposed to light. This reset the Pi, and turned out to be a very educational introduction to photons and energy levels for thousands of people with a Pi.

The best guess from the EEVblog is that a chip on the offending board handles a differential signal going to the flex circuit. This chip is sensitive to light, and shutting it down with photons allows the other half of the differential signal to take over. It’s a hand-wavy explanation, but then again this is a very, very weird problem.

You can check out [dyril]’s video demonstration of the problem and solution below. Thanks [Rasz] for sending this one in.

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Shark With Frickin’ LED Tells People Not To Bother You

January 1, 2016 by Dan Maloney 5 Comments

Everybody is busy these days, but sometimes it’s hard to tell. What with teleconferences being conducted over tiny Bluetooth headphones and Skype meetings where we seem to be dozing in front of the monitor, we’ve lost some of the visual cues that used to advertise our availability. So why not help your colleagues to know when to give you space with this shark themed WiFi-enabled meeting light?

Why a shark and not a mutated intemperate sea bass? Only [falldeaf] can answer that. But the particulars of the build are well-documented and pretty straightforward. A Photon runs the show, looking for an Outlook VFB file to parse. An RGB LED is used to change the color of the translucent 3D printed shark based on whether you’re in a meeting, about to step into one, or free. The case is 3D printed as well, although [falldeaf] farmed the prints out to a commercial printing outfit because of the size and intricacy of the parts. He did fabricate a nice looking wood base for the light, though.

There are plenty of ways to tell people to buzz off, but this is a pretty slick solution. For those in open floor plan workspaces, something like this IoT traffic light for you and your cube-mates might be in order.

Representation of cosmic light hitting a smartphone's screen.

Detect Cosmic Rays With Your Smartphone Using CRAYFIS

October 17, 2014 by Theodora Fabio 6 Comments

[Daniel Whiteson and Michael Mulhearn], researchers at the University of California, have come up with a novel method of detecting ultra-high energy cosmic rays (UHECR) using smartphones. UHECR are defined as having energy greater than 10¹⁸eV. They are rare and very difficult to detect with current arrays. In order to examine enough air showers to detect UHECR, more surface area is needed. Current arrays, like the Pierre Auger Observatory and AGASA, cannot get much larger without dramatically increasing cost. A similar THP Quarterfinalist project is the construction of a low-cost cosmic ray observatory, where it was mentioned that more detection area is needed in order to obtain enough data to be useful.

[Daniel Whiteson and Michael Mulhearn] and colleagues noted that smartphone cameras with CMOS sensors can detect ionizing radiation, which means they also will pick up muons and high-energy photons from cosmic rays. The ubiquitous presence of smartphones makes their collective detection of air showers and UHECR an intriguing possibility. To make all this happen, [Whiteson and Mulhearn] created a smartphone app called CRAYFIS, short for Cosmic RAYs Found In Smartphones. The app turns an idle smartphone into a cosmic ray detector. When the screen goes to sleep and the camera is face-down, CRAYFIS starts taking data from the camera. If a cosmic ray hits the CMOS sensor, the image data is stored on the smartphone along with the arrival time and the phone’s geolocation. This information is uploaded to a central server via the phone’s WiFi. The user does not have to interact with the app beyond installing it. It’s worth noting that CRAYFIS will only capture when the phone is plugged in, so no worries about dead batteries.

The goal of CRAYFIS is to have a minimum of one million smartphones running the app, with a density of 1000 smartphones per square kilometer. As an incentive, anyone whose smartphone data is used in a future scientific paper will be listed as an author. There are CRAYFIS app versions for Android and iOS platforms according to the site. CRAYFIS is still in beta, so the apps aren’t publicly available. Head over to the site to join up!

[via Science]

Quantum Cryptography In-band Attack

October 6, 2008 by Eliot 10 Comments

Quantum cryptography is an emerging field, but low install base hasn’t kept researchers from exploring attacks against it. It’s an attractive technology because an attacker sniffing the key exchange changes the quantum state of the photons involved. All eavesdroppers can be detected because of this fundamental principal of quantum mechanics.

We’ve seen theoretical side-channel attacks on the hardware being used, but had yet to see an in-band attack until now. [Vadim Makarov] from the University of Science and Technology in Trondheim has done exactly that (Internet Archive). Quantum key distribution systems are designed to cope with noise and [Makarov] has taken advantage of this. The attack works by firing a bright flash of light at all the detectors in the system. This raises the amount of light necessary for a reading to register. The attacker then sends the photon they want detected, which has enough energy to be read by the intended detector, but not enough for the others. Since it doesn’t clear the threshold, the detectors don’t throw any exceptions. The attacker could sniff the entire key and replay it undetected.

This is a very interesting attack since it’s legitimate eavesdropping of the key. It will probably be mitigated using better monitoring of power fluctuations at the detectors.

[via I)ruid]