Subterranean Uses For LIDAR: Cave Surveys

December 28, 2019 by Sharon Lin 11 Comments

LIDAR has gained much popularity as a means for self-driving cars to survey the space around them. At their most basic, LIDAR is a surveying method that uses lasers to paints the space around the sensors and assembles the distances measured from reflected light into a digital three-dimensional representation. That’s something that has quite a number of other applications, from surveying ancient ruins and rainforests from a bird’s eye view to developing 3D models of indoor spaces.

One fascinating use of LIDAR technology is to map out the routes inside caves, subterranean spaces that are seldom accessed by humans apart from those with specialized equipment and knowledge of how to safely traverse the underground terrain. [caver.adam] has been working on his Open LIDAR project for a few years using an SF30-B High Speed Rangefinder and laser device for a dual-system atop a gimbal with stepper motors for cave scanning.

Originally an entry in the 2016 Hackaday Prize, [Adam] has continued to work on the project. The result shown in the video below is a cheaper 3D LIDAR setup that works by rotating the laser distance module on 2 axes with a sensor centered at the center of rotation. It works for volumetric calculations, detects change over time, and identifies various water patterns and rocks on a surface map. Compared to notebooks, tape measures, and compasses, it’s certainly a step up in cave surveying technology.

Check out some other past underground surveying projects, such as Iowa City’s beer caves scanning projects and National Geographic’s 2014 expedition of the Titan Chamber in southern Guizhou Province in China.

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Magic-Angle Twisted Bilayer Graphene – Yes, That’s The Scientific Name

December 27, 2019 by Sharon Lin 14 Comments

In the world of physics research, graphene has been gaining popularity as one of the most remarkable materials in the last 15 years. While it may appear unassuming in common household goods such as pencil leads, the material boasts a higher strength than steel and a higher flexibility than paper. On top of all that, it is also ultra-light and an excellent conductor of electric current and heat.

Recently, physicists from the Massachusetts Institute of Technology discovered that stacking two sheets of graphene and twisting a small angle between them reveals an entire new field of material science – twistronics. In a paper published in Nature, researchers have taken a look into this new material, known as the magic-angle twisted bilayer graphene. By modifying the graphene’s temperature, they were able to cause the material to shift from behaving like an insulator to transforming into a superconductor.

A graphic in the New York Times demonstrates some of the interesting properties that arise from stacking and twisting two sheets. Scientists have long known that graphene is a one-layer-thick honeycombed pattern of carbon atoms, but actually separating a single sheet of graphene has been fairly difficult. A low-tech method pioneered by two physicists at the University of Manchester involves using sticky tape to pull apart graphene layers until a single layer is left.

Small imperfections that arise from slightly misaligned sheets manifests in a pattern that allows electrons to hop between atoms in regions where the lattice line up, but unable to flow in regions that are misaligned. The slower moving electrons are thus more likely to interact with each other, becoming “strongly correlated”.

The technique for measuring the properties of this new twisted graphene is similarly low-tech. After a single layer of graphene is separated by sticky tape, the tape is torn in half to reveal two halves with perfectly aligned lattices. One of the sides is rotated by about 1.3 degrees and pressed onto the other. Sometimes, the layers would snap back into alignment, but other times they would end up at 1.1 degrees and stop rotating.

When the layers were cooled to a fraction of a degree above absolute zero, they were observed to become a superconductor, an incredibly discovery for the physicists involved in the experiment. Further studies showed that different permutations of temperature, magnetic field, and electron density were also able to turn the graphene into a superconductor. On top of this, the graphene was also able to exhibit a form of magnetism arising from the movement of electrons rather than the intrinsic properties of the atoms. With so many possibilities still unexplored, it’s certain that twistronics will reveal some remarkable findings pretty soon.

[Thanks Adrian for the tip!]

A Car That Runs On Homemade Chemical Reactions

December 25, 2019 by Sharon Lin 11 Comments

The race for chemical engineering is quite literally on. Every year, the American Institute of Chemical Engineers (AlChE) brings together hundreds of university students to face-off to design the fastest car using techniques they’ve learned from chemical engineering courses.

The Chem-E-Car competition races cars which are only powered by chemical reactions. The goal is to come up with an elegant solution – you can’t simply jettison matter out the back as the method of locomotion. In particular, the rules don’t allow the use of liquid or obnoxious odor discharge, commercial batteries, brakes, or electrical/mechanical timing devices. However, this doesn’t mean that electronics are absent from these designs. Many teams must gather data in order to design a control system to improve the performance of their car.

Students have to build a power system, stopping mechanism, circuitry, and mechanical assembly for the body of the car, all to fit in a size constraint not much bigger than a shoebox. The competition primarily judges the accuracy of the chemical reaction for stopping the car more so than speed or power. Given that the load the car must carry is typically unknown until the day of the competition, this is a significant challenge, allowing teams to find a way to design a flexible reaction that can accommodate a range of loads and distances.

For example, this 2015 entry from the Rice University team (PDF) uses a fuel cell for locomotion and an iodine clock reaction as a timer for braking. The fuel cell powers an Arduino which monitors a light-dependent resistor. In between the LED and that LDR, the clock reaction turns opaque at a predictable time and triggers the motors to stop turning.

While many schools choose not to disclose their designs in order to gain a competitive edge, we applaud the teams who have shared the story of their builds. Kudos to the Rice team mentioned above, to the 2014 Rutger’s team whose white paper outlines the construction of aluminum air batteries worthy of Walter White, to the car from the Universitas Negeri Semarang, Indonesia powered by a thermoelectric generator (PDF), the UC Berkeley team for outlining numerous approaches to developing their power system, and the two Ohio State team’s entries seen winning the regional competition in the video below.

If you were on a team that compete the the Chem-E-Car, we want to hear about it!

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Ted The Talking Toaster

December 23, 2019 by Sharon Lin 9 Comments

The team behind [8 Bits and a Byte] have built a talking toaster. More accurately, they retrofitted their existing toaster with some hardware components to make it appear to talk and get angry at its users. While the actual toaster functionality isn’t necessary for the build, it certainly allows the project to have a more whimsical vibe.

The project uses a Raspberry Pi 3 and a Google AIY kit, consisting of a HAT, microphone, and speaker. Servos control the movement of the toaster’s eyebrows with the help of the HAT. Some decorative materials in the form of googly eyes and pipe cleaners help bring other features of the talking toaster to life.

The control flow for the chatbot makes use of Google’s speech-to-text for picking up text from audio input, the Dialogflow API to match intent, and Text-to-Speech to pipeline possible answer back to the Raspberry Pi to play over a speaker. They also used Remo.tv to broadcast live updates from the toaster to anyone on an online feed, allowing users in a chatroom to talk directly to Ted.

While Ted’s communications may be quite limited, there’s certainly no limit to the number of interactions he’ll be having online now!

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The Birth Of The Modern Robot

December 19, 2019 by Sharon Lin 26 Comments

When Isaac Asmiov was writing I, Robot, the field of robotics was still in its infancy. As he notes in The Complete Robot, as the field began to mature, it started showing signs of conforming to the popular ideas held by science fiction writers about what robotics ought to be. Notions of humanoid robots, the functions that robots would have in domestic settings, even the ethical quandaries that AI ethicists face today were all themes of early sci-fi writers.

The idea of a robot – at least of automata – predates the field of robotics. The idea of an independent automata may have existed as early as the ancient Egyptians Chinese, and Greeks, who attempted to build self-operated machines that resembled animals and humans. Myths of clay golems in Jewish legends and clay giants in Norse legends perpetuated the idea of an artificial being that could mimic the actions of living creatures. A 400 BC myth from Crete spoke of a man of bronze who guarded their island from pirates.

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Using Glow-in-the-Dark Fish Gut Bacteria To Make Art

December 7, 2019 by Sharon Lin 3 Comments

In New Orleans, a Loyola University professor has been creating original art out of glow-in-the-dark fish gut bacteria, enough to fill 1000 Petri dishes. Her first major foray into art was biomorphic abstractions, inspired by Impressionist painters, with her current work reflecting much of the abstraction of the earlier style.

The bacteria comes from the Pacific Rock Fish and glows a vibrant electric-blue. It is typically kept in a freezer and has a texture and color similar to water when it’s being used. The luminescence only lasts for 24 hours, presenting timing challenges when preparing artwork for a photoshoot, as artist [Hunter Cole] often does. With a Q-tip, [Cole] paints roses, lilies, and insects onto the Petri dishes and arranges them for surreal photography shoots. In addition to painting shapes in agar, she uses a light painting technique by filling clear water bottles with the bacteria for long-exposure shots.

[Cole] is planning on presenting her work at an art exhibit in New Orleans, along with showcasing a performance piece featuring models clad in chandelier-like costumes glowing with bioluminescent bacteria in petri dishes.

Upgrade Your Shades To Find Lost Items

December 7, 2019 by Sharon Lin 8 Comments

Ever wish you could augment your sense of sight?

[Nick Bild]’s latest hack helps you find objects (or people) by locating their position and tracking them with a laser. The device, dubbed Artemis, latches onto your eyeglasses and can be configured to locate a specific object.

Images collected from the device are streamed to an NVIDIA Jetson AGX Xavier board, which uses a SSD300 (Single Shot MultiBox Detection) model to locate objects. The model was pre-trained with the COCO dataset to recognize and localize 80 different object types given input from images thresholded in OpenCV. Once the desired object is identified and located, a laser diode activates.

Probably due to the current thresholds, the demo runs mostly work on objects placed further apart against a neutral background. It’s an interesting look at applications combining computer vision with physical devices to augment experiences, rather than simply processing and analyzing data.

The device uses two servos for controlling the laser: one for X-axis control and the other for Y-axis control. The controls are executed from an Adafruit Itsy Bitsy M4 Express microcontroller.

Perhaps with a bit more training, we might not have so much trouble with “Where’s Waldo” puzzles anymore.

Check out some of our other sunglasses hacks, from home automation to using LCDs to lessening the glare from headlights.

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