Transforming EDF Backpack For A Speed Boost

February 3, 2024 by Danie Conradie 18 Comments

Fighting against a tough headwind on your daily cycle can be a drag, but [Emiel] of The Practical Engineer, has a loud and bold solution. In the Dutch video after the break, he builds a transforming backpack with two electric ducted fans (EDFs), and takes to the bike paths.

An EDF moves a small volume of air at high velocity, which doesn’t make them great for low speed applications. But they’re nice and compact, and safer than large propellers. [Emiel] didn’t skimp on the rest of the hardware, with the motors attached to metal 3D printed arms, mounted on a machined aluminum steel plate.

The arms were printed courtesy of a sponsor, and created via generative design in Fusion 360 to make them both light and strong. A pair of large servos swing the arms up, while smaller servos rotate the motors into the horizontal position. The arm servos are controlled by an Arduino, and activated by a simple toggle switch attached to the backpack’s shoulder strap. A wireless remote similar to that of an electric skateboard is used to control the EDFs.

Fitted in a [Emiel]’s old backpack, the result looks somewhat innocuous (if you don’t look too closely) until it unfolds its hidden power—twin jets ready to blast away any pesky headwinds with the push of a button. It’s a fun solution that is sure to attract attention, and a great excuse to create heavy duty mechanics.

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Electric Boomerang Does Laps

February 2, 2024 by Danie Conradie 5 Comments

Boomerangs are known for their unique ability to circle back to the thrower, but what if you could harness this characteristic for powered for free flight? In a project that spins the traditional in a new direction, [RCLifeOn] electrifies a boomerang to make it fly laps.

The project started with several of the 3D printed boomerang designs floating around on the internet, and adding motor mounts to the tips. [RCLifeOn] is no stranger to RC adventures, and his stockpile of spare parts from previous flying and floating projects proved invaluable. He added motor mounts and mounted all the electronics, including a RC receiver for controlling the throttle, but first iteration didn’t have enough lift, so the boomerang and motors were scaled up.

[RCLifeOn] launched the contraptions by letting them spin on the end of a stick until they achieve lift-off. The second iteration still couldn’t quite get into the air, but after increasing the blade angles using a heat gun it was flying laps around the field.

Although we’ve seen spinning drones that are controllable, it would be no small control systems challenge to make it completely RC controlled. In the meantime this project is a fun, if somewhat risky way to mix the traditional with modern tech.

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An Alternative Orientation For 3D Printed Enclosures

February 2, 2024 by Danie Conradie 29 Comments

When it comes to 3D printing, the orientation of your print can have a significant impact on strength, aesthetics, and functionality or ease of printing. The folks at Slant 3D have found that printing enclosures at a 45° provides an excellent balance of these properties, with some added advantages for high volume printing. The trick is to prevent the part from falling over when balance on a edge, but in the video after the break [Gabe Bentz] demonstrate Slant 3D’s solution of minimalist custom supports.

The traditional vertical or horizontal orientations come with drawbacks like excessive post-processing and weak layer alignment. Printing at 45° reduces waste and strengthens the end product by aligning the layer lines in a way that resists splitting across common stress points. When scaling up production, this orientation comes with the added advantage of minimal bed contact area, allowing the printer to auto-eject the part by pushing it off the bed with print head.

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The Case Against Calibration Cubes

February 2, 2024 by Danie Conradie 27 Comments

Calibration cubes have long been a staple for testing and adjusting 3D printers, but according to [Stefan] of CNC Kitchen, they’re not just ineffective—they could be leading us astray. In the video after the break he explains his reasoning for this controversial claim, and provides a viable alternative.

Such cubes are often used to calibrate the steps per millimeter for the printer’s steppers, but the actual dimensions of said cube can be impacted by over or under extrusion, in addition to how far the machine might be out of alignment. This can be further exacerbated by measuring errors due to elephant’s foot, over extruded corners, or just inaccuracies in the caliper. All these potential errors which can go unnoticed in the small 20 x 20 mm cube, while still leading to significant dimensional errors in larger prints

So what’s the solution? Not another cube. It’s something called the “CaliFlower” from [Adam] of Vector 3D. This is not a typical calibration model — it’s carefully designed to minimize measurement errors with ten internal and external measuring points with stops for your calipers. The model costs $5, but for your money you get a complete guide and spreadsheet to calculate the required of corrections needed in your firmware or slicer settings.

If you regularly switch materials in your 3D printer, [Stefan] also advises against adjusting steps per millimeter and suggests defining a scaling factor for each material type instead. With this method validated across different materials like PLA, PETG, ABS, and ASA, it becomes evident that material shrinkage plays a significant role in dimensional inaccuracy, not just machine error. While [Stefan] makes a convincing case against the standard calibration cube for dimensional calibration, he notes that is is still useful for evaluating general print quality and settings.

[Stefan] has always done rigorous testing to back his claims, and this video was no different. He has also tested the effects of filament color on part strength, the practicality of annealing parts in salt, and even printing custom filament.

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A Concrete Solution To Balance And Protect Camera Gear

February 1, 2024 by Danie Conradie 15 Comments

Knocking over expensive camera equipment is an unfortunate occupational hazard when filming projects in a workshop. [Dane Kouttron] wanted to stop sacrificing lights to the cause, so he came up with a practical use for a weeble: A self-stabilizing monopod.

Inspired by a giant scale weeble built by [Colin Furze], [Dane] first did the math to determine the parameters for the build. It’s all about achieving torque equilibrium with a hemisphere of concrete, and [Dane] walks us through the equations, arriving at the conclusion that a 2 lb. camera on 4 foot pole, one needs a hemisphere with a mass of 28 lbs. and a radius of just under 4 inches. To achieve this weight in the given volume would require extra dense concrete with steel shot added.

After some CAD work and 3D printing the 4-part mold was assembled, with RTV silicone sealant acting as both adhesive between the parts and mold release agent. [Dane] first did a test mold with concrete he had laying around. With success achieved, he pursued the real mix but had issues with an error in the concrete-water ratio and the difficulty of mixing in the steel shot. On the second attempt he managed to extract a functional hemisphere from the mold, with the pole held in position during curing by a 3D printed bracket.

The hemisphere bottom of the hemisphere has a flat spot to keep it stable when bumped lightly. [Dane] added a Manfroto quick-release mount to the end of the pole to allow easy attachment of lights and cameras. It might be a bit hefty to carry around, but it’s takes up less floor space than a tripod and is sure to save [Dane] from expensive bumps-turned-crashes.

Camera cranes, small and large, are another great tool for workshop cinematography. For sheer overkill it would be hard to beat an 8-axis workshop-sized motion control robot.

High Caliber Engineering On A Low Torque PCB Servo Motor

January 31, 2024 by Danie Conradie 6 Comments

Building a 3D motor printed motor is one thing, but creating a completely custom servo motor with encoder requires some significant engineering. In the video after the break [365 Robots] takes us through the build process of a closed-loop motor with a custom optical encoder.

The motor, an axial flux design, uses a stack of 0.2mm PCBs with wedge shaped coils clamped in a 3D printed body. It’s similar to some of the other PCB motors we’ve featured, but what really sets this build apart is its custom optical encoder, which was a project in its own right. The 4-bit absolute position encoder uses IR LEDs to shine through an PCB disc with concentric gray code copper encoder rings onto IR receivers. This works because FR4, the composite material used in PCBs doesn’t block IR light.

The motor’s body was printed from ABS to withstand the heat during operation. [365 Robots] didn’t skimp on the testing either, creating a 3D printed closed-loop test stand with load cell and Arduino. Like other PCB motors it produces very little torque, roughly 2% of a typical NEMA17 stepper motor. Even so, the engineering behind this project remains impressive.

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3D Mouse With 3D Printed Flexures And PCB Coils

January 31, 2024 by Danie Conradie 7 Comments

3D mice with six degrees of freedom (6DOF) motion are highly valued by professional CAD users. However, the entry-level versions typically cost upwards of $150 and are produced by a single manufacturer. [Colton Baldridge] has created the OS3M Mouse — an open source alternative using PCB coils and 3D printed flexures.

The primary challenges in creating a 6DOF input device, similar to the 3Dconnexion Space Mouse, lie in developing a mechanical coupling that enables full range motion, and electronics capable of precisely and consistently measuring this motion. After several iterations of printed flexure combinations and trip down the finite element analysis (FEA) rabbit hole, [Colton] had a working single-piece mechanical solution.

To measure the knob’s movement accurately, [Colton] employs inductive sensing. Inductance to Digital Converters (LDCs) assess the inductive alterations across three pairs of PCB coils, each having an opposing metal disk mounted on the knob. This setup allows [Colton] to use a Stewart platform‘s kinematic model calculate the knob’s relative position. The calculation are done on an STM32 which also acts USB HID send the position data to a computer. For the demo [Colton] created a simple C++ app to translate the position data to Solidworks API calls.

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