Building A Full-Fat Air Quality Monitor

September 3, 2019 by Maya Posch 13 Comments

Over the years many people have made an air quality monitor station, usually of some configuration which measures particulates (PM_2.5 & PM₁₀). Some will also measure ozone (O₃), but very few will meet the requirements that will allow one to calculate the Air Quality Index (AQI) as used by the EPA and other organizations. [Ryan Kinnett]’s project is one of those AQI-capable stations.

The AQI requires the measurement of the aforementioned PM_2.5 (µg/m³), PM₁₀ (µg/m³) and O₃ (ppb), but also CO (ppm), SO₂ (ppb) and NO₂ (ppb), all of which has to be done with specific sensitivities and tolerances. This means getting sensitive enough sensors that are also calibrated. [Ryan] found a company called Spec Sensors who sell sensors which are pretty much perfect for this goal.

Using Spec Sensor’s Ultra-Low Power Sensor Modules (ULPSM) for ozone, nitrogen-dioxide, carbon monoxide and sulfur dioxide, a BME280 for air temperature, pressure and relative humidity, as well as a Plantower PMS5003 laser particle counter and an ADS1115 ADC, a package was created that fit nicely alongside an ESP8266-based NodeMCU board, making for a convenient way to read out these sensors. The total one-off BOM cost is about $250.

The resulting data can be read out and the AQI calculated from them, giving the desired results. Originally [Ryan] had planned to take this sensor package along for a ride around Los Angeles, to get more AQI data than the EPA currently provides, but with the time it takes for the sensors to stabilize and average readings (1 hour) it would take a very long time to get the readings across a large area.

Ideally many of such nodes should be installed in the area, but this would be fairly costly, which raises for [Ryan] the question of how one could take this to the level of the Air Quality Citizen Science project in the LA area. Please leave your thoughts and any tips in the comments.

A Pocket QWERTY For Arduino And More

September 3, 2019 by Kristina Panos 15 Comments

If you want to add a keypad to your Arduino project, the options are pretty limited. There’s that red and blue 4×4 membrane we’ve all seen in password-protected door lock projects, and the phone layout version that does pretty much all the same tricks. Isn’t it time for a full Arduino-compatible keyboard? [ELECTRONOOBS] thinks so.

This 41-button Arduino keyboard PCB is a stepping stone to his next project, a pair of two-way texting machines. (Which is nice, because we were totally going to suggest that). It’s based on that ubiquitous red/blue keypad, but it has a full QWERTY layout. There’s also a shift button that opens up special characters and uppercase, and the addition of return, ok, and send keys puts it over the top. The best part of this keyboard, hands down, is the soft, soundless buttons. Though you trade clicky feedback for comfort, it will be well worth it after a few dozen presses.

The keypad uses an onboard ATMega328P to scan the matrix for button presses, decode them, and send them via UART or I²C to an Arduino. [ELECTRONOOBS] has the PCB files available via Patreon for now, though they will be open in the future. The code is already available for download on his website.

Future plans include an LED to indicate when shift is pressed, and adding the special characters next to the numbers on the silkscreen (whoops!). Be sure to check out the build video after the break.

Want an Arduino-driven keyboard for longer hauls across the alphabet? Saddle up and ride this candy-colored mechanical unicorn.

Continue reading “A Pocket QWERTY For Arduino And More” →

When Project Enclosures Go Bad: A Message From The Trenches

September 3, 2019 by Maya Posch 43 Comments

A wall-mounted, electric car charging station doesn’t sound like it’d require the most exciting or complicated enclosure. This was pretty much the assumption [Mastro Gippo] and his team started out with when they decided to turn what came back from a product designer into a real enclosure for the ‘Prism’ charging hardware they had developed. As it turned out, the enclosure proved to be the most challenging part of the project.

The first thought was to make a cheap, simple prototype enclosure for integration testing. This led them through trying out FDM 3D printed enclosures, wooden enclosures, folded (glued) plastic enclosures, aluminium extruded enclosures, Zamac alloy enclosures, and finally the plastic injection molded enclosure they had been avoiding due to the high costs.

The injection mold used to produce the Prism enclosures with.

Even if it meant taking out a loan to cover the setup costs, the results really do speak for themselves with a well-integrated design and two really happy looking partners-in-business. It does make us wonder how projects lacking this kind of financial leeway can get professional-grade enclosures without breaking the proverbial bank.

FDM 3D printing is always getting better and with a lot of post-processing you can have one enclosure that looks great, but that doesn’t scale. Outsourcing it to a professional 3D printing company like Shapeways is better, but it’s still not injection-molding quality and if the product is successful you’ll eventually invert the cost/benefit you were shooting for in the first place. Where is the middle ground on great-looking enclosures? Please let us know your experiences and thoughts in the comments.

Dian Fossey, Gorilla Girl

September 3, 2019 by Kristina Panos 37 Comments

Few people sacrifice themselves as completely as Dian Fossey did for the mountain gorillas of Africa. She fought tirelessly to protect them from poachers, cattle herders, zoo kidnappers, corrupt governments, and tourists. Dian left a comfortable life behind to make the misty slopes of an extinct volcano her home and headquarters. There, she patiently sought out the gorillas, mimicking their facial expressions and actions until they grew curious about her. Eventually, she had their complete trust and friendship, and considered them her family.

Dian spent eighteen years on and off living among the gorillas. She continually risked her health, life, and reputation to raise awareness of their plight and save them from extinction. While the mountain gorilla remains an endangered species, Dian’s research and conservation efforts have greatly contributed to their increased population in the years since her death.

Continue reading “Dian Fossey, Gorilla Girl” →

Clean Water Technologies Hack Chat

September 3, 2019 by Dan Maloney 2 Comments

Join us on Wednesday, September 4th at noon Pacific for the Clean Water Technologies Hack Chat with Ryan Beltrán!

Access to clean water is something that’s all too easy to take for granted. When the tap is turned, delivering water that won’t sicken or kill you when you drink it, we generally stop worrying. But for millions around the world, getting clean water is a daily struggle, with disease and death often being the penalty for drinking from a compromised source. Thankfully, a wide range of water technologies is available to help secure access to clean water. Most are expensive, though, especially at the scale needed to supply even a small village.

Seeing a need to think smaller, Ryan started MakeWater.org, a non-profit program that seeks to give anyone the power to make clean water through electrocoagulation, or the use of electric charge to precipitate contaminants from water. There’s more to MakeWater than electrocoagulation kits, though. By partnering with STEM students and their teachers, MakeWater seeks to crowdsource improvements to the technology, incorporating student design changes into the next version of the kit. They also hope to inspire students to develop the skills they need to tackle real-world problems and make a difference in the lives of millions.

Our Hack Chats are live community events in the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Wednesday, September 4 at 12:00 PM Pacific time. If time zones have got you down, we have a handy time zone converter.

Click that speech bubble to the right, and you’ll be taken directly to the Hack Chat group on Hackaday.io. You don’t have to wait until Wednesday; join whenever you want and you can see what the community is talking about.

This Machine Learning Algorithm Is Meta

September 3, 2019 by Bryan Cockfield 20 Comments

Suppose you ran a website releasing many articles per day about various topics, all following a general theme. And suppose that your website allowed for a comments section for discussion on those topics. Unless you are brand new to the Internet, you’ll also imagine that the comments section needs at least a little bit of moderation to filter out spam, off topic, or even toxic comments. If you don’t want to employ any people for this task, you could try this machine learning algorithm instead.

[Ladvien] goes through a general overview of how to set up a convolutional neural network (CNN) which can be programmed to do many things, but this one crawls a web page, gathers data, and also makes decisions regarding that data. In this case, the task is to identify toxic comments but the goal is not to achieve the sharpest sword in the comment moderator’s armory, but to learn more about how CNNs work.

Written in Python, the process outlines the code itself and how it behaves, setting up a small server to host the neural network, and finally creating the webservice. As with any machine learning, you need a reliable dataset to use for training and this one came from Wikipedia comments previously flagged by humans. Trolling nuance is thrown aside, as the example homes in on blatant insults and vulgarity.

While [Ladvien] notes that his guide isn’t meant to be comprehensive, but rather to fill in some gaps that he noticed within other guides like this, we find this to be an interesting read. He also mentioned that, in theory, this tool could be used to predict the number of comments following an article like this very one based on the language in the article. We’ll leave that one as an academic exercise for now, probably.

3D Printing May Be The Key To Practical Scramjets

September 3, 2019 by Tom Nardi 32 Comments

The first scramjet, an airbreathing jet engine capable of pushing an aircraft beyond Mach 5, was successfully flown in the early 1990s. But while pretty much any other technology you could imagine has progressed by leaps and bounds in the nearly 30 years that have passed, the state-of-the-art in hypersonic scramjets hasn’t moved much. We still don’t have practical hypersonic aircraft, military or otherwise, and any missiles that travel at those sort of speeds are rocket powered.

This is somewhat surprising since, at least on paper, the operating principle of the scramjet is simplicity itself. Air rushing into the engine is compressed by the geometry of the inlet, fuel is added, the mixture is ignited, and the resulting flow of expanded gases leaves the engine faster than it entered. There aren’t even any moving parts inside of a scramjet, it’s little more than a carefully shaped tube with fuel injectors and ignitors in it.

Unfortunately, pulling it off in practice is quite a bit harder. Part of the problem is that a scramjet doesn’t actually start working until the air entering the engine’s inlet is moving at around Mach 4, which makes testing them difficult and expensive. It’s possible to do it in a specially designed wind tunnel, but practically speaking, it ends up being easier to mount the engine to the front of a conventional rocket and get it up to speed that way. The downside is that such flights are one-way tickets, and end with the test article crashing into the ocean once it runs out of fuel.

But the bigger problem is that the core concept is deceptively simple. It’s easy to say you’ll just squirt some jet fuel into the stream of compressed air and light it up, but when that air is moving at thousands of miles per hour, keeping it burning is no small feat. Because of this, the operation of a scramjet has often been likened to trying to light a match in a hurricane; the challenge isn’t in the task, but in the environment you’re trying to perform it in.

Now, both Aerojet Rocketdyne and Northrop Grumman think they may have found the solution: additive manufacturing. By 3D printing their scramjet engines, they can not only iterate through design revisions faster, but produce them far cheaper than they’ve been able to in the past. Even more importantly, it enables complex internal engine geometries that would have been more difficult to produce via traditional manufacturing.

Continue reading “3D Printing May Be The Key To Practical Scramjets” →