As described in this project’s write-up, “The brachistochrone curve is a classic physics problem, that derives the fastest path between two points A and B which are at different elevations.” In other words, if you have a ramp leading down to another point, what’s the quickest route?
Intuitively—and incorrectly—you might think this is a straight line, and while you could work out the solution mathematically, this rig releases three marbles at a time, letting them cruise down to the Arduino Uno-based timing mechanism to see which path is fastest.
The ramps are made out of laser-cut acrylic, and the marbles each strike a microswitch to indicate they’ve finished the race. The build looks like a great way to cement a classic physics problem in students’ minds, and learn even more while constructing the contraption!
Fluoride can be healthy in certain concentrations, but above a certain level it instead has the opposite effect, causing serious dental and bone diseases. While the cost and benefit of any substance use has to be carefully weighted, up until now, verification that water source isn’t contaminated—above just 2 ppm—has been the purview of well-equipped laboratories.
Researchers at EPFL in Lausanne, Switzerland, however, have come up with a technique that can accurately determine fluoride concentrations using only a few drops of water. The key to this development is a new compound known as SION-105, which is normally luminescent, but darkens when it encounters fluoride. This means that instead of more expensive laboratory equipment, UV LEDs can be used with a photodiode to quantitatively measure the substance’s appearance, and thus the quantity of fluoride in drinking water.
From the images in EPFL’s write-up, the prototype test apparatus appears to utilize several commonly available components, including an Arduino Uno and small OLED display for user feedback.
Published in the Journal of the American Chemical Society (JACS), the device is named SION-105, is portable, considerably cheaper than current methods, and can be used on-site by virtually anyone.
The key to the device is the design of a novel material that the scientists synthesized (and after which the device is named). The material belongs to the family of “metal-organic frameworks” (MOFs), compounds made up of a metal ion (or a cluster of metal ions) connected to organic ligands, thus forming one-, two-, or three-dimensional structures. Because of their structural versatility, MOFs can be used in an ever-growing list of applications, e.g. separating petrochemicals, detoxing water, and getting hydrogen or even gold out of it.
SION-105 is luminescent by default, but darkens when it encounters fluoride ions. “Add a few droplets of water and by monitoring the color change of the MOF one can say whether it is safe to drink the water or not,” explains Mish Ebrahim, the paper’s first author. “This can now be done on-site, without any chemical expertise.”
We were glued to our screens last month as NASA successfully landed the InSight module on Mars. (Bet you were, too.) What an amazing sight a Martian sunrise turns out to be! Now, we’ve got the bug. The bigtime Space Bug. Accordingly, our final Humble Bundle ebook deal of […]
More often than not, our coverage of projects here at Hackaday tends to be one-off sort of thing. We find something interesting, write it up for our beloved readers, and keep it moving. There’s an unending world of hacks and creations out there, and not a lot of time to cover them all. Still, it’s nice when we occasionally see a project we’ve previously covered “out in the wild” so to speak. A reminder that, while a project’s time on the Hackaday front page might be fleeting, their journey is far from finished.
A perfect example can be found in a recent article posted by the BBC about the battle with noise in Barcelona’s Plaza del Sol. The Plaza is a popular meeting place for tourists and residents alike, with loud parties continuing into the middle of the night, those with homes overlooking the Plaza were struggling to sleep. But to get any changes made, they needed a way to prove to the city council that the noise was beyond reasonable levels.
Enter the Smart Citizen, an open source Arduino-compatible sensor platform developed by Fab Lab Barcelona. We originally covered the Smart Citizen board back in 2013, right after it ran a successful funding campaign on Kickstarter. Armed with the data collected by Smart Citizen sensors deployed around the Plaza, the council has enacted measures to try to quiet things down before midnight.
Today people tend to approach crowdfunded projects with a healthy dose of apprehension, so it’s nice to see validation that they aren’t all flash in the pan ideas. Some of them really do end up making a positive impact, years after the campaign ends.
Wave tanks are cool, but it’s likely you don’t have one sitting on your coffee table at home. They’re more likely something you’ve seen in a documentary about oil tankers or icebergs. That need no longer be the case – you can build yourself a wave generator at home!
This build comes to use from [TVMiller] who started by creating a small tank out of acrylic sheet. Servo-actuated paddles are then placed in the tank to generate the periodic motion in the water. Two servos are controlled by an Arduino, allowing a variety of simple and more complex waves to be created in the tank. [TVMiller] has graciously provided the code for the project on Hackaday.io. We’d love to see more detail behind the tank build itself, too – like how the edges were sealed, and how the paddles are hinged.
A wave machine might not be the first thing that comes to mind when doing science at home, but with today’s hardware, it’s remarkable how simple it is to create one. Bonus points if you scale this up to the pool in your backyard – make sure to hit the tip line when you do.
[Philip Nicovich] has been building laser sequencers over at the University of New South Wales. His platform is used to sequence laser excitation on his fluorescence microscopy systems. In [Philip]’s case, these systems are used for super-resolution microscopy, that is breaking the diffraction limit allowing the imaging of structures of only a few nanometers (1 millionth of a millimeter) in size.
Using an Arduino shield he designed in Eagle, [Philip] was able to build the system for less than half the cost of a commercial platform.
The control system is build around the simple Arduino shield shown to the right, which uses simple 74 series logic to send TTL control signals to the laser diodes used in his rig. The Arduino runs code which allows laser firing sequences to be programmed and executed.
[Philip] also provides scripts which show how the Arduino can be interfaced with the open source micro manager control software.
As well as the schematics [Philip] has provided STEP files and drawings for the enclosure and mounts used in the system and a detailed BOM.
More useful than all this perhaps is the comprehensive write-up he provides. This describes the motivation for decisions such as the use of aluminum over steel due to its ability to transfer heat more effectively, and not to use thermal paste due to out-gassing.
While I can almost hear the cries of “not a hack”, the growing use of open source platforms and tool in academia fills us with joy. Thanks for the write-up [Philip] we look forward to hearing more about your laser systems in the future!