Lamp Sheds Light On Air Quality

June 3, 2021 by Kristina Panos 4 Comments

It can be difficult to appreciate when the air quality is decent and when it’s poor, unless conditions are so bad that you can literally see the smog hanging in the air. Rather than try to digest a bunch of air quality numbers, [guillaume_slizewicz] built Canari — a lovely lamp that sheds light on the air pollution problem by taking local air quality data and turning it into light patterns.

Canari is of course named after the brave birds that once alerted miners to dangerous air conditions before they were forced to switch to carbon monoxide sensors. This bird has a Raspberry Pi Zero W that gets air quality data from a public API and controls the lights with a PWM bonnet based on the concentration of particulates in the air. The more particulates, the dimmer the LEDs are, and the faster they fade in and out.

The main piece of data that Canari grabs is the amount of particulate matter, and the display can switch between representing the level of PM2.5 (particulate matter with diameter less than 2.5 micrometers) in the air and PM10. Check out the demo and setup video after the break.

More of a numbers person? All you really need is a microcontroller, an air quality sensor, and a display.

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Air Extractor Automatically Gives AC A Boost

June 3, 2021 by Stephen Ogier 39 Comments

Portable air conditioning units are a great way to cool off a space during the hot summer months, but they require some place to blow the heat they’ve removed from your room. [VincentMakes] got a portable AC unit for his home, but he found that the place he wanted to put it was too far from the only window he could use to dump the hot air. Having too long of a duct on the hot air exhaust increases the back pressure on the fan which could cause it to prematurely fail, so [Vincent] used an extractor fan to automatically give is AC unit’s exhaust a boost on its way to the window.

Because his AC can operate at low, medium, and high speeds, he chose an extractor fan that also supported multiple speeds and took care to match the airflow of the AC and extractor fan to avoid putting too much strain on either fan. He designed a system to automatically set the speed of the boosting fan to match that of the AC using a Hall effect current sensor to measure the AC unit’s power draw and an Arduino Nano for control. A custom PCB interfaces the Nano to the Hall Sensor and control relays, and we have to applaud [Vincent] for keeping the +5V DC and 230V AC far, far away from each other. In addition to this fine electronics work, [Vincent] also built an enclosure for the fan controller that allows the fan to be mounted on top at an angle, which helps avoid having hard bends in the exhaust duct.

If this has you thinking about smart air conditioners to keep cool this summer, check out this ESP8266-powered smart AC system, or this Raspberry Pi-based system that controls both AC and blinds!

Aircraft Compass Teardown

May 30, 2021 by Al Williams 6 Comments

We didn’t know what a C-2400 LP was before we saw [David’s] video below, but it turned out to be pretty interesting. The device is an aircraft compass and after replacing it, he decided to take it apart for us. Turns out, that like a nautical compass, these devices need adjustment for all the metal around them. But while a ship’s compass has huge steel balls for that purpose, the tiny and lightweight aviation compass has to be a bit more parsimonious.

The little device that stands in for a binnacle’s compensators — often called Kelvin’s balls — is almost like a mechanical watch. Tiny gears and ratchets, all in brass. Apparently, the device is pretty reliable since the date on this one is 1966.

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Repairing A Vintage HP 9825 The Hard Way

May 19, 2021 by Jonathan Bennett 16 Comments

[CuriousMarc] is at it again, this time trying to undo the damage from a poorly designed power circuit, that fried the internals of his HP 9825 computer. (Video, embedded below.)

The power supply on this particular model has a failure mode where a dying transistor can lead to 13 V on the 5 V line. This causes all the havoc one would expect on the internals of a 1970s era portable computer. This particular computer is rather rare, so instead of calling it a lost cause, our protagonist decides to replace the faulty transistor, install a proper overvoltage protection circuit, and then start the tedious hunt for which chips actually let their magic smoke out.
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Do You Really Own It? Motorcycle Airbag Requires Additional Purchase To Inflate

May 18, 2021 by Al Williams 218 Comments

If you ride a motorcycle, you may have noticed that the cost of airbag vests has dropped. In one case, something very different is going on here. As reported by Motherboard, you can pick up a KLIM Ai-1 for $400 but the airbag built into it will not function until unlocked with an additional purchase, and a big one at that. So do you really own the vest for $400?

Given the nature of the electronics and computer business lately, we spend a good bit of time thinking of what it means to own a piece of technology. Do you own your cable modem or cell phone if you aren’t allowed to open it up? Do you own a piece of software that wants to call home periodically and won’t let you stop it? Sometimes it makes sense that you are paying for a service. But there have been times where, for example, a speaker company essentially bricks devices that could work fine on their own even though you — in theory — own the device.

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Projecting Moving Images In Air With Lasers

May 17, 2021 by Al Williams 14 Comments

You’ve seen it a million times in science fiction movies and TV shows: a moving holographic display. From Princess Leia asking for help to virtual tennis on Total Recall, it is a common enough idea. [Dan Smalley]’s team at BYU has made progress in projecting moving 3D images in thin air. While they might not be movie quality, they are a start, and, after all, you have to start somewhere.

The display traps a small particle in the air with a laser beam and then moves that particle around, leaving behind an illuminated path in the air. You can see the effect in the video below. The full paper explains how a type of ray tracing allows the relatively small optical trap display to appear larger and more fluid. While it does make images seem to appear behind the display’s actual volume, it also requires eye tracking to work since the illusion only works from a certain perspective.

These are not, of course, technically holograms. That’s actually an advantage in some cases because holograms require a tremendous amount of data that increases rapidly as the size of a display scales up. The optical trap display uses a much more manageable data rate.

We’ve seen optical trap displays before. In fact, volumetric displays seem to be all the rage lately.

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Hackaday Podcast 118: Apple AirTag Hacked, Infill Without Perimeters, Hair-Pulling Robots, And Unpacking The 555

May 14, 2021 by Mike Szczys 5 Comments

Hackaday editors Elliot Williams and Mike Szczys gather to ooh and aah over a week of interesting hacks. This week we’re delighted to welcome special guest Kristina Panos to talk about the Inputs of Interest series she has been working on over the last couple of years. In the news is the effort to pwn the new Apple AirTags, with much success over the past week. We look at turning a screenless Wacom tablet into something more using a donor iPad, stare right into the heart of a dozen 555 die shots, and watch what happens when you only 3D print the infill and leave the perimeters out.

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 (~55 MB)