Kill the Exhaust, Not Your Lungs with the Fume Coffin

As if slinging around 40 watts of potentially tattoo-removing or retina-singeing laser beams wasn’t anxiety-inducing enough, now comes a new, scary acronym – LCAGs, or “laser-generated airborne contaminants.” With something that scary floating around your shop, it might be a good idea to build a souped-up laser cutter exhaust fan to save your lungs.

We jest, but taking care of yourself is the responsible way to have a long and fruitful hacking career, and while [patternmusic]’s “Fume Coffin” might seem like overkill, can you go too far to protect your lungs? Plywood and acrylic, the most common materials that come across a laser cutter’s bed, both release quite a witch’s brew of toxins when vaporized by a laser beam. The Fume Coffin clears the air in your shop by venting it to the outdoors after giving it a good scrubbing through an activated charcoal pre-filter and a HEPA polishing element. Both filters are commercially available so replacements won’t be an issue, and the entire thing is housed in a wooden box that gives the device its name.

Since it’s ejecting 200 cubic feet per minute, you’ll have to provide at least that much make-up air, but other than that the Fume Coffin should be a welcome addition to the shop. We’ve seen a few other attempts to handle LCAGs effectively before, including a DIY charcoal and automotive air filter design.

Oscillating Fan Controller Used As Relay

The most brilliant hacks we see aren’t always the thousand-dollar, multi-year projects spanning every facet of engineering. Rather, the most ingenious projects are ones that take an everyday thing and use it in a simple but revolutionary way. By that measure, it’ll be hard to top [Robert]’s latest hack which uses the controller board from an everyday oscillating fan to build a three-way remote-controlled relay board.

Most oscillating fans have a speed selector switch. What that does might be somewhat different between different types of fan, but in general it will select either a smaller portion of the fan’s motor to energize or switch in a resistor which will have the same speed-lowering effect. [Robert]’s fan had little more than a triple-throw switch on the control board, so when he decided the fan wasn’t worth keeping anymore, he was able to re-purpose the control board into a general-use relay. As a bonus, the fan could be controlled by infrared, so he can also remote control whatever he decides to plug into his new piece of equipment.

While this simple hack might not change the world, it may give anyone with an old fan some ideas for other uses for its parts. If you want to do a little more work and get the fan itself running again, though, it is possible to rebuild the whole thing from the ground up as well.

Tiny Pipe Organ Needs Tiny Church

There are a lot of unusual listings on eBay. If you’re wondering why someone would have a need for shredded cash, or a switchblade comb, or some “unicorn meat” (whatever that is), we’re honestly wondering the same thing. Sometimes, though, a listing that most people would consider bizarre finds its way to the workbench of someone with a little imagination. That was the case when [tinkartank] found three pipe organ pipes on eBay, bought them, and then built his own drivers.

The pipes have pitches of C, D, and F# (which make, as far we can tell, a C add9 flat5 no3 chord). [tinkartank] started by firing up the CNC machine and creating an enclosure to mount the pipes to. He added a church-like embellishment to the front window, and then started working on the controls for the pipes. Each pipe has its own fan, each salvaged from a hot air gun. The three are controlled with an Arduino. [tinkartank] notes that the fan noise is audible over the pipes, but there does seem to be an adequate amount of air going to each pipe.

This project is a good start towards a fully functional organ, provided [tinkartank] gets lucky enough to find the rest of the pipes from the organ. He’s already dreaming about building a full-sized organ of sorts, but in the meantime it might be interesting to use his existing pipes to build something from Myst.

Hackaday Prize Entry: AutoFan Saves Tired Drivers With Face Recognition

Long distance driving can be tedious at times. The glare of the sun and the greenhouse effect of all your car’s windows make it hot and dry. You turn on the fan, or air conditioning if you have it, and that brings relief. Soon enough you’ve got another problem, the cold dry air is uncomfortable on your eyes. Eventually as you become more tired, you find yourself needing the air on your face more and more as you stay alert. You thus spend most of the journey fiddling with your vents or adjusting the climate controls. Wouldn’t it be great if the car could do all that for you?

AutoFan is a project from [hanno] that aims to automate this process intelligently. It has a fan with steerable louvres, driven by a Raspberry Pi 2 with attached webcam. The Pi computes the position of the driver’s face, and ensures the air from the fan is directed to one side of it. If it sees the driver’s blink rate increasing it directs the air to their face, having detected that they are becoming tired.

The build logs go into detail on the mathematics of calculating servo angles and correcting for camera lens distortion in OpenCV. They also discuss the Python code used to take advantage of the multicore architecture, and to control the servos. The prototype fan housing can be seen in the video below the break, complete with an unimpressed-looking cat. For those of you interested in the code, he has made it available in a GitHub repository.

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We’re Fans of Dave’s Fans contributor extraordinaire [davedarko] gets hot in the summer. We all do. But what separates him from the casual hacker is that he beat the heat by ordering four 120 mm case fans. He then 3D printed a minimalistic tower frame for the fans, and tied them all together with a ULN2004 and an ESP8266. The whole thing is controlled over the network via MQTT. That’s dedication to staying cool.

We really like the aesthetics of this design. A fan made up of fans! But from personal experience, we also know that these large case fans can push a lot of air fairly quietly. That’s important if you’re going to stand something like this up on your desk. While we’re not sure that a desk fan really needs networked individual PWM speed control, we can see the temptation.

Now that they’re individually controlled, nothing stops [davedarko] from turning this into a musical instrument, or even using the fans to transmit data. The only thing we wouldn’t do, despite the temptation to stick our fingers in the blades, is to complicate the design visually. Maybe that would finally teach the cat not to walk around on our desk.

When the Smart Hits the Fan

A fan used to be a simple device – motor rotates blades, air moves, and if you were feeling fancy, maybe the whole thing oscillates. Now fans have thermostats, timers, and IR remotes. So why not increase the complexity by making a smart fan with an IoT interface?

[Casper]’s project looks more like a proof of concept or learning platform than a serious attempt at home automation. His build log mentions an early iteration based on a Raspberry Pi. But an ESP8266 was a better choice and made it into the final build, which uses an IR LED to mimic the signals from the remote so that all the stock modes of the fan are supported. The whole thing is battery powered and sits on a breadboard on top of the fan, but we’ll bet that a little surgery could implant the interface and steal power internally. As for interfaces, take your pick – an iOS app via the SmartThings home automation platform, through their SmartTiles web client, or using an Amazon Echo. [Casper] mentions looking into MQTT as well but having some confusion; we’d suggest he check out [Elliot Williams]’ new tutorial on MQTT to get up to speed.

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Flying Planes With Squirrel Cages

Fixed wing remote control planes are ridiculously overpowered. Whereas normal, manned fixed wing aircraft need to take into account things like density altitude, angle of attack, and weight limits, most RC aircraft can hover. This insane amount of power means there’s a lot of room for experimentation, especially in new and novel power plants. [Samm Sheperd] had an old squirrel cage fan taken from an electric wall heater and figured one man’s trash was an integral part of another man’s hobby and built a plane around this very unusual fan.

squirrel-cage-fan-wideThe only part of the squirrel cage fan [Samm] reused was the impeller. Every other part of this power plant was either constructed out of foam board, plywood, or in the case of the brushless motor turning the fan, stolen from the ubiquitous box of junk on every modeller’s workbench.

The design of the plane puts the blower fan directly under the wings, blasting the air backwards underneath the empennage. During testing, [Samm] found this blower pulled around 350W from the battery – exactly what it should draw if a properly sized propeller were attached to the motor. The thrust produced isn’t that great — only about 400g of thrust from an airframe that weights 863g. That’s very underpowered for an RC aircraft, but absurdly powerful for any manned flying machine.

Does the plane work? Of course it does. [Samm] took his plane for a few laps around the neighborhood and found the plane flies excellently. It is horrifically loud, but it is a great example of how much anyone can do with cheap RC planes constructed out of foam.

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