CPAP Hacked into Super Charged 3D Printer Cooler

Of all the parts on your average desktop 3D printer, the nozzle itself is arguably where the real magic happens. Above the nozzle, plastic is being heated to the precise temperature required to get it flowing smoothly. Immediately below the nozzle there’s a fan blowing to get the plastic cooled back down again. This carefully balanced arrangement of heating and cooling is the secret that makes high quality fused deposition modeling (FDM) printing possible.

But as it turns out, getting the plastic hot ends up being easier than cooling it back down again. The harsh reality is that most of the fans small enough to hang on the side of a 3D printer nozzle are pretty weak. They lack the power to push the volume of air necessary to get the plastic cooled down fast enough. But with his latest project, [Mark Rehorst] hopes to change that. Rather than using some anemic little fan that would be better suited blowing on the heatsink of a Raspberry Pi, he’s using a hacked CPAP machine to deliver some serious airflow.

The brilliance of using a CPAP machine for this hack is two-fold. For one, the machine uses a powerful centrifugal fan rather than the wimpy axial “muffin” fans we usually see on 3D printers. Second, the CPAP pushes air down a lightweight and flexible hose, which means the device itself doesn’t have to be physically mounted to the printer head. All you need is manifold around the printer’s nozzle that connects up to the CPAP hose. This “remote” fan setup means the print head is lighter, which translates (potentially) into higher speed and acceleration.

[Mark] was able to connect the fan MOSFET on his printer’s SmoothieBoard controller up to the brushless motor driver from the CPAP motor, which lets the printer control this monster new fan. As far as the software is concerned, nothing has changed.

He hasn’t come up with a manifold design that’s really optimized yet, but initial tests look promising. But even without a highly optimized outlet for the air, this setup is already superior to the traditional part cooler designs since it’s got more power and gets the fan motor off of the print head.

Getting your 3D printed parts to cool down is serious business, and it’s only going to get harder as printers get faster. We wouldn’t be surprised if fan setups like this start becoming more common on higher-end printers.

Benchtop Fume Extractor Cuts the Cord, Clears the Air

What good is safety gear that isn’t used because it’s annoying and gets in the way of getting the job at hand completed? None, really, and the solder fume extractor is one item that never seems to live in harmony with your workspace. They’re often noisy, they obstruct your vision, and a power cord draped across your bench is a sure way to ruin your soldering zen.

To fix those problems, [Nate] has built a nice battery powered solder fume extractor that’s so low profile and so quiet, you won’t mind sharing a bench with it. Based on a standard 80-mm case fan, the extractor has a built-in 18650 battery for power and a USB charging port. There are nice little features, like a speed control and a low-battery indicator. The fan mounts to a pair of custom PCBs, which form the feet for the fan. [Nate] claims to have run the fan for 12 hours straight on battery before needing a charge, and that it’s so quiet he needs to add a power indicator to the next version. Also making an appearance in rev 2 will be a carbon filter to catch the fumes, but as [Nate] notes, better to spread them around for now than let them go directly up his nose.

Are you in the hacking arts for the long haul? Let’s hope so. If you are, make sure you’re up on the basics of mitigating inhalation hazards.

16-Cylinder Stirling Engine Gets a Tune Up

Tiny catapults, kinetic sculptures, a Newton’s Cradle — all kinds of nifty toys can adorn the desk of the executive in your life. On the high end of the scale, a 16-cylinder butane-powered Stirling engine makes a nice statement, but when it comes equipped with a propeller that looks ready for finger-chopping, some mods might be in order before bestowing the gift.

We don’t knock [JohnnyQ90] for buying a rotary Stirling engine from one of the usual sources rather than building, of course. With his micro Tesla turbine and various nitro-powered tools, he’s proven that he has the machining chops to scratch-build one of these engines. And it wasn’t just the digit dicing potential of the OEM engine that inspired him. There was a little too much slop in the bearings for his liking, so he machined a new bearing block and shaft extension. With a 3D-printed shroud, a small computer fan, and snappy brass nose cone, the engine started looking more like a small jet engine. And the addition of a pulley and a small generator gave the engine something interesting to do. What’s more, the increased airflow over the cold end of the engine boosted performance.

Need the basics of Stirling engines? Here’s a quick look at the 200-year history of these remarkable devices.

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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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