Day: June 28, 2026

Hack Improves Cheap Speed Controllers

June 28, 2026 by 4 Comments

[Tony Goacher] has worked with a lot of cheap brushless DC motor controllers built in China. They can be very cost-effective, but sometimes limited in performance or capability, particularly when it comes to low-speed operation. Thus, he’s been working on a project to make cheap controllers more capable.

The prime problems [Tony] has faced are jerkiness, throttle deadspots, and inconsistent torque delivery at low speeds. This is especially the case when running brushless motors on heavier vehicles, where the greater inertia can compound any minor problems to the point things become undriveable. [Tony]’s solution has been to create a signal interceptor that lives in between a throttle and the cheap motor controller to change their overall behavior.

The demo vehicle for this build is TrakTrike, a sort of bicycle-half-track hybrid that [Tony] built for EMF Camp 2022. After blowing up some nicer controllers, [Tony] specced some cheaper parts from AliExpress. Only, the low-speed control was terrible, and the dual motor controllers didn’t respond identically to throttle and would cause the vehicle to steer or crab, making driving difficult. This was fixed by dropping in an Arduino Nano after the throttle, and before the two motor controllers. It allows calibrating the throttle output from the Arduino to eliminate dead spots, while also tuning the throttle output to left and right motors individually so they respond more similarly. There are also custom acceleration and deceleration curves that make the controllers respond more smoothly, and a precise crawling speed for consistent low-speed maneuvering.

Just by doing some fancy throttle smoothing and control, [Tony] was able to greatly improve the usability of these cheap controllers, for the price of an Arduino Nano and little more. Files are on GitHub for those eager to attempt the hack themselves. There are other ways to go about this of course, like diving into field-oriented control, if you’re so inclined. Alternatively, speculate on how you’d tackle this engineering challenge down in the comments.

Make Your Own Loudspeaker From Scratch

June 28, 2026 by 1 Comment

A loudspeaker is a vital component of every device that plays sound, but while its operation is simple, it’s a surprisingly difficult device to build. [Rvanderouderaa] has made an Instructables post showing a speaker design that it’s claimed, had an impedance that varies by volume (Dutch language, Google Translate link).

In all moving-coil speakers, a coil of wire is held in a radial magnetic field. To this is attached a cone, and when a current is passed through the coil the whole thing moves to create the sound. The tricky part of making one comes in making the cone itself, and in particular the suspension system that holds it in place while allowing it to move backwards and forwards. It’s normal for these components to be moulded from thick paper.

This design uses a 3D printed frame and cone, with the 3D printing providing excellent rigidity. The suspension system is a circular corrugated sheet, and it’s made in this case using papier-maché made from wet toilet paper, and a 3D printed mould. We particularly like this technique.

This is an impressive build, simply for having made a recognizable and working speaker in the first place. There’s no demo video so we have no idea how it sounds, but for us the point is more in the construction than the reproduction.

If speakers interest you, we’ve taken an in-depth look at them in the past.