brushless motor

68 Articles

An E-Bike Motor From First Principles

May 14, 2026 by 9 Comments

Many of us have made electric transport of some form, whether a Hacky Racer, and e-bike, a go-kart, or whatever. We have invariably bought a motor, or if we are really adventurous, repurposed a car alternator. Not [Birdbrain] though, because she’s designed and built her own from first principles.

The video below goes into significant detail on the design of her motor, looking at cores, wire sixes, and configurations with a useful simulation along the way. We particularly like the way she uses a bandsaw to cut transformer laminations to shape for her core. The 3D printed housing initially isn’t strong enough for the forces induced by the magnets, but she attacks that problem with a new print. The motor works well, and as an added bonus there’s an introduction to the different types of motor driver. It seems the cheap ones don’t deliver a good waveform for the characteristics of the motor. Sadly she doesn’t fit it to a real bike in the video, but it seems this thing might just work.

If you lack the courage to make the whole thing from scratch, we took a quick look at the car alternator route a while back.

Continue reading “An E-Bike Motor From First Principles” →

Portable Tow Rope Batman Would Be Proud Of

March 6, 2026 by 16 Comments

Out of all of Batman’s massive array of tools which turn a relatively ordinary person into a superhero, perhaps his most utilitarian is his grappling gun — allowing him the ability to soar around his city like Spiderman or Superman. [John Boss] isn’t typically fighting crime, but he did develop his own grappling gun of sorts which gives him another superpower: the ability to easily scale snowy hills to quickly get back to the top.

The grappling gun takes inspiration from a commonly used tool called a power ascender, which is often used in industry applications where climbing is required. This one is held in the hand and uses a brushless motor with a belt-driven 3:1 reduction for increased torque. The pulley system, bearings, and motor are all housed in a 3D printed enclosure and are powered by rechargeable Milwaukee power tool batteries. During prototyping the rope intake and output feed locations had to be moved to increase the pulley’s grabbing ability, and with a working prototype he swapped a lot of the plastic 3D printed parts out for metal to increase the sturdiness of the device.

The grappling gun was originally designed for a smaller child to get hoisted up a hill on a sled, but when stress testing the device [John] found out that it actually has more than enough capability to haul even an adult up a hill on skis. As an added bonus, the outfeed for the rope can be put into a bag and used to automatically coil the rope up when he’s done at the hill. Although this is a great solution for a portable rope tow, for something more permanent and more powerful take a look at this backyard rope tow that was built from spare parts.

Continue reading “Portable Tow Rope Batman Would Be Proud Of” →

A round, 3D-printed motor housing is shown, with one flattened side holding a fan mount. A circular plate is mounted above the face of the housing, and a cord runs around it and pulleys on the side of the housing.

Tying Up Loose Ends On A Rope-based Robot Actuator

January 5, 2026 by 9 Comments

One of the perennial challenges of building robots is minimizing the size and weight of drive systems while preserving power. One established way to do this, at least on robots with joints, is to fit each joint with a quasi-direct-drive motor integrating a brushless motor and gearbox in one device. [The 5439 Workshop] wanted to take this approach with his own robot project, but since commercial drives were beyond his budget, he designed his own powerful, printable actuator.

The motor reducing mechanism was the biggest challenge: most quasi-direct drives use a planetary gearbox, but this would have been difficult to 3D-print without either serious backlash or limited torque. A cycloidal drive was an option, but previous printable cycloidal drives seemed to have low efficiency, and they didn’t want to work with a strain-wave gearing. Instead, he decided to use a rope drive (this seems to be another name for a kind of Capstan drive), which doesn’t require particularly strong materials or high precision. These normally use a rope wound around two side-by-side drums, which are difficult to integrate into a compact actuator, but he solved the issue by putting the drums in-line with the motor, with two pairs of pulleys guiding the rope between them in a “C” shaped path.

The actual motor is a hand-wound stator inside a 3D-printed rotor with magnets epoxied into it. The printed rotor proved problematic when the attraction between the rotor and magnets caused it to flex and scrape against the housing, and it eventually had to be reinforced with some thin metal sheets. After fixing this, it reached five Newton-meters of torque at one amp and nine Newton-meters at five amps. The diminishing returns seem to be because the 3D-printed pulley wheels broke under higher torque, which should be easy to fix in the future.

This looks like a promising design, but if you don’t need the output shaft inline with the motors, it’s probably easier to build a simple Capstan drive, the mathematics of which we’ve covered before. Both makers we’ve previously seen build Capstan drives used them to make robot dogs, which says something for their speed and responsiveness.

Hydrofoil Bikes Are Harder To Build Than You Think

November 27, 2025 by 7 Comments

Hydrofoils are perhaps best known for their application on boring ferries and scary boats that go too fast. However, as [RCLifeOn] demonstrates, you can also use them to build fun and quirky personal watercraft. Like a hydrofoil bike! Only, there are some challenges involved.

Hydrofoils work much like airfoils in air. The shape of the foil creates lift, raising the attached vehicle out of the water. This allows the creation of a craft that can travel more quickly because the majority of its body is not subject drag from the water. The key is to design the craft such that the hydrofoils remain at the right angle and depth to keep the craft lifted out of the water while remaining stable.

The hydrofoil bike is created out of a combination of plywood, foam, and 3D printed components. It uses a powerful brushless motor for propulsion, and that’s about it. Sadly, despite the simplicity, it wasn’t an instant success. As you might expect, balancing on the bike is quite difficult, particularly when trying to get it started—as the foils need some speed to actually start generating meaningful lift.

After further research into commercial hydrofoil bikes, [RCLifeOn] realized that the buoyancy of the bike made it too hard to straddle when starting out. Some of the 3D printed foils also proved more than a little fragile. It’s back to the drawing board for now—the power system is likely up to snuff, but the dynamics of the platform need work. It’s perhaps no surprise; we’ve covered the challenges of hydrofoil stability before. If you want to go fast on water, you could go the easier route and just build an electric surfboard. Video after the break.

Continue reading “Hydrofoil Bikes Are Harder To Build Than You Think” →

A dismantled drill on a cluttered workbench

Going Brushless: Salvaging A Dead Drill

January 29, 2025 by 26 Comments

Let’s face it—seeing a good tool go to waste is heartbreaking. So when his cordless drill’s motor gave up after some unfortunate exposure to the elements, [Chaz] wasn’t about to bin it. Instead, he embarked on a brave journey to breathe new life into the machine by swapping its dying brushed motor for a sleek brushless upgrade.

Things got real as [Chaz] dismantled the drill, comparing its guts to a salvaged portable bandsaw motor. What looked like an easy swap soon became a true hacker’s challenge: incompatible gear systems, dodgy windings, and warped laminations. Not discouraged by that, he dreamed up a hybrid solution: 3D-printing a custom adapter to make the brushless motor fit snugly into the existing housing.

The trickiest part was designing a speed control mechanism for the brushless motor—an impressively solved puzzle. After some serious elbow grease and ingenuity, the franken-drill emerged better than ever. We’ve seen some brushless hacks before, and this is worth adding to the list. A great tool hack and successful way to save an old beloved drill. Go ahead and check out the video below!

Continue reading “Going Brushless: Salvaging A Dead Drill” →

Brushless ESC Becomes Dual-Motor Brushed ESC With A Few Changes

February 15, 2024 by 15 Comments

What is a brushless ESC, really? Well, generally, it’s usually a microcontroller with a whole lot of power transistors hanging off it to drive three phases of brushless motor coils. [Frank Zhao] realised that with a little reprogramming, you could simply use a brushless ESC to independently run two brushed motors. Thus, he whipped up a custom firmware for various AM32-compatible ESCs to do just that.

The idea of the project is to enable a single lightweight ESC to run two brushed motors for combat robots. Dual-motor brushed ESCs can be hard to find and expensive, whereas single-motor brushless ESCs are readily available. The trick is to wire up the two brushed motors such that each motor gets one phase wire of its own, and the two motors share the middle phase wire. This allows independent control of both motors via the brushless ESC’s three half-bridges, by setting the middle wire to half voltage. Depending on how you set it up, the system can be configured in a variety of ways to suit different situations.

[Frank’s] firmware is available on Github for the curious. He lists compatible ESCs there, and notes that you’ll need to install the AM32 ESC firmware before flashing his version to make everything work correctly.

The VESC project has long supported brushed motor operation, too, though not in a tandem configuration. Meanwhile, if you’ve got your own neat ESC hacks, don’t hesitate to hit us up on the tipsline!

Electric Boomerang Does Laps

February 2, 2024 by 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.

Continue reading “Electric Boomerang Does Laps” →