This Smart Watch Keeps An Eye On Ambient CO2 Levels

Human respiration takes in oxygen and in turn, we exhale carbon dioxide. Thus, an uptick of carbon dioxide levels around us can indicate we’re in the presence of other humans, and also, perhaps, the pathogens they carry. To explore this phenomenon, [C Scott Ananian] developed a mod for the Watchy open-source smartwatch, which lets it detect carbon dioxide.

The idea behind the build is simple. If you’re around increased CO2 levels, it may be because you’re surrounded by people, and thus more likely to be exposed to COVID-19. To detect CO2, the watch relies on a Sensiron SCD40 or SCD41 sensor. This is read by the Watchy’s ESP32 microcontroller, and results are graphed on the watch’s e-Paper display. The Watchy is also given a nice new aluminum case to fit the additional hardware.

It’s cool having a graph on your wrist of the ambient concentration of CO2, and at the very least, it could make a good talking point next time you’re at a particularly boring party. You’ll also be more than ready to advise other partygoers if the carbon dioxide level is reaching dangerous levels.

We’ve seen similar builds before, which are useful not only for pandemic safety but also for monitoring if you have any leaks from CO2 storage in the house. If you’ve been working on your own ways to track dangerous gases, be sure to drop us a line!

Skeleton Watches You Intensely Because It’s Halloween, Okay

If you’ve ever seen a painting in which the eyes follow you around the room, you might have found that a bit uneasy. [CuriousInventor] has taken that concept further with a skeleton that literally holds a gaze on anyone in its field of view. 

The heart of the system is a Raspberry Pi Zero, fitted with a Pi Camera. Running OpenCV, code is set up to track humans and turn the skeleton’s head to face any that are detected. This is achieved via a servo in the skeleton’s neck. A servo bonnet is used to drive the servos without unnecessarily straining the Raspberry Pi.

The skeleton itself doesn’t look modified in any way, though most of the electronics are mounted inside a pretty obvious plastic box. We’d love to see a version 2 with all the hardware housed neatly inside the skull.

It’s a fun hack that makes for an enjoyable Halloween decoration. OpenCV can do other useful things, too, however, like spotting weeds. Video after the break.

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Cheap Caliper Hack Keeps ‘Em Running Longer

Many a hacker is a fan of the cheapest calipers on the market. Manufactured in China and priced low enough that they’re virtually disposable, they get a lot of jobs done in the world where clinical accuracy isn’t required. However, their batteries often die when left in a drawer for a long time. [Ben] was sick of that, and got to hacking.

The result was a quick-and-dirty mod that allows the calipers to be powered by a AAA battery. The average AAA cell has 5-10 times the capacity of the typical LR44 coin cells used in these devices.

[Ben] whipped this up with an eye to making it work rather than making it nice, so there are some shortcuts taken. The battery housing was 3D-printed on the lowest-quality settings that were viable, and it’s held to the calipers with hot glue. Similarly, bare wire ends were used instead of proper contacts, taking advantage of the battery being crammed in to make a good connection.

It’s a hack that will likely save [Ben] much frustration, as he’ll now rarely open his drawer to find his calipers dead. However, one [Pete Prodoehl] suggests another useful trick: store the calipers in the closed position with the lock screw tight to save them turning themselves on accidentally.

Whichever way you go, you’ve hopefully learned something today that will keep your cheap calipers working when you need them. Next, you might consider hacking them to capture data, too.

This Eyeball Watches You Thanks To Kinect Tracking

Eyeballs are often watching us, but they’re usually embedded in the skull of another human or animal. When they’re staring at you by themselves, they can be altogether more creepy. This Halloween project from [allpartscombined] aims to elicit that exact spooky vibe.

The project relies on a Kinect V2 to do body tracking. It feeds data to a Unity app that figures out how to aim the eyeball at any humans detected in the scene. The app sends angle data to an Arduino over serial, with the microcontroller generating the necessary signals to command servos which move the eyeball.

With tilt and pan servos fitted and the precision tracking from the Kinect data, the eye can be aimed at people  in two dimensions. It’s significantly spookier than simply panning the eye back and forth.

The build was actually created by modifying an earlier project to create an airsoft turret, something we’ve seen a few times around these parts. Fundamentally, the tracking part is the same, just in this case, the eye doesn’t shoot at people… yet! Video after the break.

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Photo of an arid desert landscape

How Practical Is Harvesting Water From The Air?

Water is one of the most precious substances required to sustain human life. Unfortunately, in some areas like California, it’s starting to run out.

The ongoing drought has some people looking towards alternative solutions, such as sucking water out of the very air itself. In particular, a company called Tsunami Products has been making waves in the press with its atmospheric water generators, touting them as a solution for troubled drought-stricken areas, as reported by AP News. Today, we’ll look at how these machine capture water, and whether or not they can help in areas short on water.

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Fixing A Broken Game Installer By Sheer Force Of Will

These days, we seldom purchase games on physical media. Even when buying titles from yesteryear, we usually download them from an online service. Some of these older games haven’t been properly ported to their new delivery platform, as [Slortibort] found out. Thus, it was time to dive into the game files and sort the problem out.

The game in question was the Hammers of Fate expansion pack for the base game Heroes of Might and Magic V. [Slortibort’s] partner bought it from Ubisoft, and ran the installer. However, the installer would report that it couldn’t find the original files from the base game, and fail to start.

Fixing the issue was no mean feat, requiring use of the Sexy Installshield Decompiler to dive into the guts of the installer to see what was going wrong. In the end, it came down to some registry key shenanigans, but the route of how [Slortibort] got there is well worth the read.

It’s a fine example of some of the issues around moving games to digital distribution; proper attention must be paid to do it right. Even then, there’s always the risk you’ll lose your games down the track. There are benefits, of course, but there’s always a tradeoff to be made.

Speaker ‘Stun Gun’ Aims To Combat China’s Dancing Grannies

One of the more popular social activities in China is group dancing in public squares. Often the pastime of many middle-aged and older women, participants are colloquially referred to as “dancing grannies.” While the activity is relatively wholesome, some dancers have begun to draw the ire of their neighbourhoods with their loud music and attempts to dominate the use of public parks and recreational areas.

Naturally, a technological solution sprung up promising to solve the problem. The South China Morning Post has reported on a “stun gun” device which claims to neutralise speakers from a distance, in an effort to shut down dance gatherings. The device created a huge stir on social media, as well as many questions about how it could work. It’s simpler, and a bit less cool, than you think. Continue reading “Speaker ‘Stun Gun’ Aims To Combat China’s Dancing Grannies” →