Hackaday Prize Entry: Gas Grenade Helps Instead of Exploding

If someone lobs a grenade, it’s fair to expect that something unpleasant is going to happen. Tear gas grenades are often used by riot police to disperse an unruly crowd, and the military might use a smoke grenade as cover to advance on an armed position, or to mark a location in need of an airstrike. But some gas grenades are meant to help, not hurt, like this talking gas-sensing grenade that’s a 2015 Hackaday Prize entry.

Confined space entry is a particularly dangerous aspect of rescue work, especially in the mining industry. A cave in or other accident can trap not only people, but also dangerous gasses, endangering victims and rescuers alike. Plenty of fancy robots have been developed that can take gas sensors deep into confined spaces ahead of rescuers, but [Eric William] figured out a cheaper way to sniff the air before entering. An MQ2 combination CO, LPG and smoke sensor is interfaced to an Arduino Nano, and a 433MHz transmitter is attached to an output. A little code measures the data from the sensors and synthesizes human voice readings which are fed to the transmitter. The whole package is stuffed into a tough, easily deployed package – a Nerf dog toy! Lobbed into a confined space, the grenade begins squawking its readings out in spoken English, which can be received by any UHF handy-talkie in range. [Eric] reports in the after-break video that he’s received signals over a block away – good standoff distance for a potentially explosive situation.

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DDR-ing a Simon Game with a Raspberry Pi

Since 1998 we’ve been privileged to partake in an arcade game known as Dance Dance Revolution, but before that, way back in the 70’s, was the Simon game. It’s essentially a memory game that asks the player to remember a series of lights and sounds. [Uberdam] decided to get the best of both worlds and mixed the two together creating this giant foot controlled Simon game. (English translation.)

The wood platform that serves as the base of the project was fitted with four capacitive sensors, each one representing a “color” on the Simon game. When a player stomps on a color, a capacitive sensor sends a signal to a relay which in turn notifies the Raspberry Pi brain of the input. The Pi also takes care of showing the player the sequence of colored squares that must be stepped on, and keeps track of a player’s progress on a projector.

This is a pretty good way of showing how a small, tiny computer like the Raspberry Pi can have applications in niche environments while also being a pretty fun game. We all remember Simon as being frustrating, and we can only imagine how jumping around on a wooden box would make it even more exciting. Now, who can build a robot that can beat this version of Simon?

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Upgrading an Old Camera with a New Light Meter

[Marc] has an old Voigtländer Vito CLR film camera. The camera originally came with an analog light meter built-in. The meter consisted of a type of solar panel hooked up to a coil and a needle. As more light reached the solar panel, the coil became energized more and more, which moved the needle farther and farther. It was a simple way of doing things, but it has a down side. The photo panels stop working over time. That’s why [Marc] decided to build a custom light meter using newer technology.

[Marc] had to work within the confines of the tiny space inside of the camera. He chose to use a LM3914 bar display driver IC as the primary component. This chip can sense an input voltage against a reference voltage and then display the result by illuminating a single LED from a row of ten LEDs.

[Marc] used a photo cell from an old calculator to detect the ambient light. This acts as a current source, but he needed a voltage source. He designed a transimpedence amplifier into his circuit to convert the current into a voltage. The circuit is powered with two 3V coil cell batteries, regulated to 5V. The 5V acts as his reference voltage for the display driver. With that in mind, [Marc] had to amplify this signal further.

It didn’t end there, though. [Marc] discovered that when sampling natural light, the system worked as intended. When he sampled light from incandescent light bulbs, he did not get the expected output. This turned out to be caused by the fact that incandescent lights flicker at a rate of 50/60 Hz. His sensor was picking this up and the sinusoidal output was causing problems in his circuit. He remedied this by adding two filtering capacitors.

The whole circuit fits on a tiny PCB that slides right into position where the original light meter used to be. It’s impressive how perfectly it fits considering everything that is happening in this circuit.

[Thanks Mojay]

Disassembled Mouse Keeps Track Of Gas Meter

After building devices that can read his home’s electricity usage, [Dave] set out to build something that could measure the other energy source to his house: his gas line. Rather than tapping into the line and measuring the gas directly, his (much safer) method was to simply monitor the gas meter itself.

The major hurdle that [Dave] had to jump was dealing with an ancient meter with absolutely no modern electronics like some other meters have that make this job a little easier. The meter has “1985” stamped on it which might be the manufacturing date, but for this meter even assuming that it’s that new might be too generous. In any event, the only option was to build something that could physically watch the spinning dial. To accomplish this, [Dave] used the sensor from an optical mouse.

The sensor is surrounded by LEDs which illuminate the dial. When the dial passes a certain point, the sensor alerts an Arduino that one revolution has occurred. Once the Arduino has this information, the rest is a piece of cake. [Dave] used KiCad to design the PCB and also had access to a laser cutter for the enclosure. It’s a great piece of modern technology that helps integrate old analog technology into the modern world. This wasn’t [Dave]’s first energy monitoring system either; be sure to check out his electricity meter that we featured a few years ago.

Vibrating Distance Torch Illuminates the Dark without Light

If you’ve ever had to move around in a dark room before, you know how frustrating it can be. This is especially true if you are in an unfamiliar place. [Brian] has attempted to help solve this problem by building a vibrating distance sensor that is intuitive to use.

The main circuit is rather simple. An Arduino is hooked up to both an ultrasonic distance sensor and a vibrating motor. The distance sensor uses sound to determine the distance of an object by calculating how long it takes for an emitted sound to return to the sensor. The sensor uses sounds that are above the range of human hearing, so no one in the vicinity will hear it. The Arduino then vibrates a motor quickly if the object is very close, or slowly if it is far away. The whole circuit is powered by a 9V battery.

The real trick to this project is that the entire thing is housed inside of an old flashlight. [Brian] used OpenSCAD to design a custom plastic mount. This mount replaces the flashlight lens and allows the ultrasonic sensor to be secured to the front of the flashlight. The flashlight housing makes the device very intuitive to use. You simply point the flashlight in front of you and press the button. Instead of shining a bright light, the flashlight vibrates to let you know if the way ahead is clear. This way the user can more easily navigate around in the dark without the risk of being seen or waking up people in the area.

This reminds us of project Tacit, which used two of these ultrasonic sensors mounted on a fingerless glove.

Hackaday Prize Entry: Telling Dad The Stove Is Off

A month ago, Hackaday landed at the NYC TechCrunch Disrupt, a bastion of people up all night on MacBooks and immense amounts of caffeine and vitamin B12. For 20 hours, everyone was typing away trying to build the next great service that would be bought by Google or Amazon or Facebook. Tucked away in one small corner of the room was the Hackaday crew, giving out dev boards, components, and advice to the few dozen hardware hackers at Disrupt. [David], one of these Hackaday enthusiasts won the Twilio Sponsorship Prize at Disrupt, and now it’s a Hackaday Prize entry.

[David]’s dad has a little bit of paranoia of accidentally leaving the stove on. This usually manifests itself a few minutes after leaving the house, which means turning the car around just to make sure the stove was off. At the TechCrunch hackathon, [David] built a small IoT device to automatically read the temperature of the stove, send that off to the Internet, and finally as an SMS via Twilio.

The hardware [David] is using is extremely minimal – a thermopile, a gas sensor, a WiFi module, and a microcontroller. There’s a lot of iterations in this project, with [David] looking at everything from TI MSP430s to Teensys to Arduinos to ESP8266 modules. Still, rough prototype thrown together in 20 hours is all you need to win the Twilio prize at Disrupt, and that’s more than enough for a very good Hackaday Prize entry.


The 2015 Hackaday Prize is sponsored by:

Earth Day: Environmental Sensors

Before you attempt to solve a problem, you must first study the problem. If there’s a problem with the environment, you must therefore study the environment at a scale never seen before. For this year’s Hackaday Prize, there are a lot of projects that aim to do just that. Here are a few of them:

[Pure Engineering]’s C12666 Micro Spectrometer has applications ranging from detecting if fruit is ripe, telling you to put sunscreen on, to detecting oil spills. Like the title says, it’s based on the Hamamatsu C12666MA spectrometer, a very tiny MEMS spectrometer that can sort light by wavelength from 340 to 780nm.

The project is to build a proper breakout board for this spectrometer. The best technologies are enabling technologies, and we can’t wait to see all the cool stuff that’s made with this sensor.

[radu.motisan]’s portable environmental monitor isn’t just one sensor, but an entire suite of them. The design of the project includes toxic and flammable gas sensors, radiation detectors, dust sensors, and radiation detectors packaged together in a neat, convenient package.

[radu] has already seen some success with environmental sensors and The Hackaday Prize; last year, his entry, the uRADMonitor placed in the top fifty for creating a global network of radiation sensors.