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If you need a truly random event generator, just wait till your next rainstorm. Whether any given spot on the ground is hit by a drop at a particular time is anyone’s guess, and such randomness is key to this simple rig that estimates the value of pi using raindrop sensors.

You may recall [AlphaPhoenix]’s recent electroshock Settlers of Catan expeditor. The idea with this less shocking build is to estimate the value of pi using the ratio of the area of a square sensor to a circular one. Simple piezo transducers serve as impact sensors that feed an Arduino and count the relative number of raindrops hitting the sensors. In the first video below, we see that as more data accumulates, the Arduino’s estimate of pi eventually converges on the well-known 3.14159 value. The second video has details of the math behind the method, plus a discussion of the real-world problems that cropped up during testing — turns out that waterproofing and grounding were both key to noise-free data from the sensor pads.

In the end, [AlphaPhoenix] isn’t proving anything new, but we like the method here and can see applications for it. What about using such sensors to detect individual popcorn kernels popping to demonstrate the Gaussian distribution? We also can’t help but think of other ways to measure raindrops; how about strain gauges that weigh the rainwater as it accumulates differentially in square and circular containers? Share your ideas in the comments below.

[via r/electronics]

Filed under: Arduino Hacks, misc hacks

For a high school science fair project, Berto Garcia came up with an idea to help reduce concussions among football players. Now a student at Texas Tech University, he holds a provisional patent for the award-winning, life-changing project.

The helmet-and-shoulder pads system consists of an Arduino connected to four sensors around the front and inside of the helmet, which is programmed to stabilize immediately after impact. When the stabilizers are not activated, players have full movement. But when a wearer suffers a hit above a certain threshold, the board activates the stabilizers, locking the helmet into place and stiffening up to reduce the whiplash motion of the neck. It doesn’t stop the impact of the initial hit, but it keeps the head from rattling around inside the helmet after the collision.

The sensors are also able to measure the amount of force with which athletes are hit and, using a radio, can wirelessly transmit that data to trainers on the sideline. Knowing that could help healthcare professionals diagnose concussions more accurately. Given recent events around concussions and traumatic brain injuries, Garcia’s idea can certainly play an imperative role in the future of sports.

Read all about the Texas Tech undergrad’s project here.


There’s no shortage of clock projects, but [niq_ro] has his own take using a vacuum fluorescent display (VFD), and Arduino, and a pair of MAX6921 ICs. Those chips are made to drive a VFD, and the use of two of the ICs required a bit of work. The Arduino is not a great time keeper, so the clock also uses a DS3231 clock module and a humidity and temperature sensor.

The clock is in Romanian, although there are some options for different text. You can find the code on GitHub and can see the result in the video below.

VFDs are often used in places where a display is meant to be read outdoors. It uses cathodoluminescence to actually generate light. The process is similar to a CRT, but at lower voltages. The tubes have a phosphor-coated anode and the cathode bombards it with electrons, making the phosphor glow. VFDs are available in different colors.

VFDs are popular for clocks, ranging from very polished looking ones, to something similar to this one, but with an MSP430. If you are interested in low-level interfacing for VFDs, we’ve talked about that too.

Filed under: Arduino Hacks, clock hacks

Do you or your significant other have trouble sticking to a budget? Well, say goodbye to overspending with the iBag2: a high-tech wearable device that helps curb your impulse buys.

The iBag2 is equipped with a Genuino Uno, a 10,000mAh power bank, and several other interesting components. There’s a timer connected to electromagnets that lock the bag according to your most vulnerable spending moments during the course of a day, an RFID system hooked up to LEDs and vibration motors that illuminate in blue and vibrate each time your wallet is taken out, as well as a built-in GPS unit that warns you when you’re near a pre-preogrammed “vulnerable spending zone.”

Aside from curtailing your expensive bad habit, the iBag2 will also reminds you every two hours via yellow lights and small vibrations when it’s time to reapply sunscreen (you know, in case you’re shopping outdoors), and a Bluetooth tracker that pings your phone if the bag is a certain distance away from you.

The wearable prototype was created by in collaboration with New York-based fashion designer Geova Rodrigues. Need a handbag that  knows when and where you’re likely to overspend? You can check out the iBag2 here.

Developed by media artist Bojana Petkovic, Swamp Orchestra is an interactive sound installation that mimics the natural chorus of swamp creatures. The project is comprised of 16 light-sensitive sound modules, with each one producing noises from insects, frogs, amphibians, birds and other organisms. Each module responds to a flashlight, and the sound varies based on the amount of the light.

Swamp orchestra seemingly functions as sound sculpture which in a subtle way changes the ambience and acoustic experience of the space but also has a substantial presence as a work of physical sculpture. The set up itself reflects the layout of a concert hall stage on a much smaller scale. The pyramid shape has been carefully chosen for its symbolism as well as modularity where three or five pyramids form the cube.

Petkovic says Swamp Orchestra is an example of the complex, multi-layered interplay between nature and machine, human intervention and artifice. The installation’s programming and electronics, according to her, are excellent examples of this.

Each light that shines above the modules represents a “personal conductor,” an oscillator controlled by an Arduino. This enables endless variations of composing the peace but also allows the participant to slow down and notice the subtleties of the composition.

A common complaint in the comments of many a Hackaday project is: Why did they use a microcontroller? It’s easy to Monday morning quarterback someone else’s design, but it’s rare to see the OP come back and actually prove that a microcontroller was the best choice. So when [GreatScott] rebuilt his recent DIY coil gun with discrete logic, we just had to get the word out.

You’ll recall from the original build that [GreatScott] was not attempting to build a brick-wall blasting electromagnetic rifle. His build was more about exploring the concepts and working up a viable control mechanism for a small coil gun, and as such he chose an Arduino to rapidly prototype his control circuit. But when taken to task for that design choice, he rose to the challenge and designed a controller using discrete NAND and NOR gates, some RS latches, and a couple of comparators. The basic control circuit was simple, but too simple for safety — a projectile stuck in the barrel could leave a coil energized indefinitely, leading to damage. What took a line of code in the Arduino sketch to fix required an additional comparator stage and an RC network to build a timer to deenergize the coil automatically. In the end the breadboarded circuit did the job, but implementing it would have required twice the space of the Arduino while offering none of the flexibility.

Not every project deserves an Arduino, and sometimes it’s pretty clear the builder either took the easy way out or was using the only trick in his or her book. Hats off to [GreatScott] for not only having the guts to justify his design, but also proving that he has the discrete logic chops to pull it off.

Filed under: Arduino Hacks, weapons hacks

img_6994The BITalino is great for biohacking — hook up the sensors and play Classic Pong with a swing of your wrist.

Read more on MAKE

The post Use BITalino to Graph Your Biosignals and Play Pong! appeared first on Make: DIY Projects and Ideas for Makers.

Maker Shuang Peng has created a 13 DOF animatronic hand using an Arduino Mega, seven servo motors, and six air cylinders, along with a Leap Motion sensor for control.

As briefly described on his Instructables page:

There are various ways to control the hand. I’ve tried the Leap Motion sensor and the data glove, which catches my motion via Processing. Then the Processing communicate with the Mega via serial. Now, I’m trying to use EMOTIV Insight EEG sensor to control it.

University of Birmingham researchers found two vulnerabilities that allow hackers to gain entry to almost all VW vehicles manufactured after 1995.A team of researchers were able to unlock and start the ignition of Volkswagen cars with just $40 of electronic components.

Read more on MAKE

The post Volkswagen Security Problems: Arduino Hack Reveals RFID Vulnerability appeared first on Make: DIY Projects and Ideas for Makers.

University of Birmingham researchers found two vulnerabilities that allow hackers to gain entry to almost all VW vehicles manufactured after 1995.A team of researchers were able to unlock and start the ignition of Volkswagen cars with just $40 of electronic components.

Read more on MAKE

The post Volkswagen Security Problems: Arduino Hack Reveals RFID Vulnerability appeared first on Make: DIY Projects and Ideas for Makers.

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