Sensor Playground Keeps Track Of Indoor Air Quality Through The Cloud

March 19, 2022 by Robin Kearey 8 Comments

When [tdw] wasn’t feeling well one day, his wife suggested that it might be due to poor air quality in their home. While an ordinary person could have simply opened a window after hearing such an idea, [tdw] instead showed his true hacker spirit and set about measuring the indoor air quality. He began by designing a simple PCB to measure CO2 and volatile organic compound (VOC) levels, but eventually broadened his scope to end up with the Sensor Playground: a plug-and-play platform to read out various sensors and store the results in the cloud.

Deliberately designed to be easy to assemble with minimal soldering skills, the Sensor Playground consists of a big two-layer PCB onto which various modules can be plugged. It supports either an ESP32 DevKit or an Adafruit Feather module to provide processing power, and provides sockets for a bunch of sensors, conveniently wired with power and SPI or I2C. It also provides a rotary encoder and two buttons for user input. All source files are available on [tdw]’s GitHub page, ready to be applied to any kind of sensing task.

[tdw] set up his Sensor Playground with sensors measuring CO2, VOC, PM2.5 (particulate matter), as well as temperature and relative humidity. A web interface allows anyone to track these measurements in real-time. The open and modular design should make it easy to extend this system with various other sensor types: we can imagine that things like solar irradiation, outside temperature and wind speed would also add useful data to the mix. Perhaps even a Geiger counter to keep track of radiation levels?

As indoor air quality sensors go, this one is definitely comprehensive and easy to use. We’ve featured other air quality sensors before, some of which also link their data to the cloud.

In 2045: Alpha Centauri

March 15, 2022 by Al Williams 90 Comments

We’ve talked about project Breakthrough Starshot which aims to send a solar sail probe to Alpha Centauri within 20 years. A little basic math and knowing that Alpha Centauri is 4.3 light years away means you are going to need to travel over 20% of the speed of light to make the trip in that time. Some new papers have proposed ways to address a few of the engineering problems.

The basic idea is simple. A very small probe is attached to a very large sail. But calling it a solar sail is a bit of a misnomer. The motive power for the sail would be a powerful laser, which provides more reliable power to the tiny probe’s propulsion system. The problems? First, the thin sail could tear under constant pressure. The answer, according to one of the papers, is to shape the sail like a parachute so it can billow under pressure.

The other problem is not burning the sail up. Space is a hard environment to dump waste heat into since radiation is the only way to transfer it. Another paper suggests that nanoscale patterns on the sail will allow it to release waste heat into the interstellar environment.

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Cheap Ghostbusters Toy Turned Convincing Prop

March 14, 2022 by Tom Nardi 2 Comments

As you might expect, the release of last year’s Ghostbusters: Afterlife has not only lead to renewed interest in the old 1980s toys and tie-in merchandise, but has spawned a whole new generation of blinking plastic gadgets to delight children of all ages. Of course, for folks like us, that means more hardware to hack on.

In a recent post to the official Ghostbusters YouTube channel, professional prop maker [Ben Eadie] shows off some of the tricks of the trade when he takes a $15 USD “PKE Meter” toy from Hasbro and turns it into a screen-quality prop. Even if you’re not looking to get an early start on your Halloween costume, the techniques demonstrated in this video could be easily adapted to other projects. For those whose next ideal home improvement is a fireman’s pole and an ectoplasmic laser-confinement grid, you might want to grab a couple of these toys while they’re still cheap for eventual conversion.

Uncovering the silver makes the piece look worn down.

The biggest takeaway from the video is probably the finishing techniques, as they could be used on any sort of realistic prop build. [Ben] starts by using a cabinet scraper to smooth out the lines on the plastic toy, and any holes are filled with the familiar baking soda and cyanoacrylate glue trick. Once the surfaces have been prepped, all the principle parts are sprayed with an adhesion promoter, followed by a coat of silver, and then the final black color.

This allows him to create a convincing “chipped paint” effect by strategically sanding or scraping through the top coat. Dabbing some toothpaste where you want the device to look worn down before spraying the final coat makes the process even faster, as it will prevent the top coat from sticking to the silver in the first place.

Unfortunately [Ben] doesn’t spend a whole lot of time explaining the electronics side of things, but it doesn’t look like there’s anything too complex going on. All the original gear is stripped, and it gets replaced with a microcontroller which we believe is an Adafruit ItsyBitsy nRF52840 Express. This is connected to two strings of tiny APA102 addressable LEDs which are run down the “wings” (we especially like the 3D printed lenses used to replace the original solid pips), and one that’s used to provide the iconic sine-wave display.

While the last PKE meter build we saw did detect radiation, we have to admit that in terms of looks, this one takes the top spot. Especially when you consider how cheap the thing was. All you need now is a Proton Pack, and you’ll be ready for Halloween.

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IoT-Enabled Mailbox Lets You Check Your Mail Without Leaving Your House

February 24, 2022 by Robin Kearey 37 Comments

Whether you live in an apartment downtown or in a detached house in the suburbs, if your mailbox is not built into your home you’ll have to go outside to see if anything’s there. But how do you prevent that dreadful feeling of disappointment when you find your mailbox empty? Well, we’re living in 2022, so today your mailbox is just another Thing to connect to the Internet of Things. And that’s exactly what [fhuable] did when he made a solar powered IoT mailbox.

The basic idea was to equip a mailbox with a camera and have it send over pictures of its contents. An ESP32-Cam module could do just that: with a 1600 x 1200 camera sensor, a 160 MHz CPU and an integrated WiFi adapter, [fhuable] just needed to write an Arduino sketch to have it take a picture every few hours and upload it to an FTP server.

A pile of components making up an IoT Mailbox — The components inside: a solar cell, battery, power controller, LDO and ESP32-Cam module with WiFi antenna

But since running a long cable all the way from the house was not an attractive option, the whole module had to be completely wireless. [fhuable] decided to power it using a single 18650 lithium ion cell, which gets topped up continuously thanks to a 1.5 W solar panel mounted on the roof of the mailbox. The other parts are housed in a 3D-printed enclosure that’s completely sealed to keep out moisture.

The enclosure had to be made from a material that does not degrade in direct sunlight, which is why [fhuable] decided to try ASA filament; this should be very resistant against UV rays, but proved tricky to process. It warped so much during cooling that the only way to get a solid piece out of the printer was to enclose the entire machine in a cardboard box to keep it warm inside.

The end result was worth it though: a neat little extension on the back of the mailbox that should keep sending photos of its insides for as long as the Sun keeps shining. The camera should also give a good indication as to the contents of the mailbox, allowing the user to ignore any junk mail; this is a useful improvement over previous IoT-enabled mailboxes that use proximity sensors, microswitches or optical sensors.

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The Electrifying Debate Around Where Lightning Comes From

February 17, 2022 by Maya Posch 26 Comments

Along with many other natural phenomena, lightning is probably familiar to most. Between its intense noise and visuals, there is also very little disagreement that getting hit by a lightning strike is a bad thing, regardless of whether you’re a fleshy human, moisture-filled plant, or conductive machine. So it’s more than a little bit strange that the underlying cause of lightning, and what makes certain clouds produce these intense voltages along ionized air molecules, is still an open scientific question.

Many of us have probably learned at some point the most popular theory about how lightning forms, namely that lightning is caused by ice particles in clouds. These ice particles interact to build up a charge, much like in a capacitor. The only issue with this theory is that this process alone will not build up a potential large enough to ionize the air between said clouds and the ground and cause the lightning strike, leaving this theory in tatters.

A recent study, using data from Earth-based radio telescopes, may now have provided fascinating details on lightning formation, and how the charge may build up sufficiently to make us Earth-based critters scurry away to safety when dark clouds draw near.

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Hackaday Podcast 155: Dual Integrating Spheres, More Magnetic Switches, PlottyBot, Red Hair In Your Wafers

February 11, 2022 by Tom Nardi 2 Comments

This week Hackaday Editor-in-Chief Elliot Williams and Managing Editor Tom Nardi take a close look at two pairs of projects that demonstrate the wildly different approaches that hackers can take while still arriving at the same conclusion. We’ll also examine the brilliant mechanism that the James Webb Space Telescope uses to adjust its mirrors, and marvel over a particularly well-developed bot that can do your handwriting for you. The finer points of living off home-grown algae will be discussed, and by the end of the show, you’ll learn the one weird trick to stopping chip fabs in their tracks.

Take a look at the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!

Direct Download (~70 MB)