A photo for a motor and a meter on a bench.

Let’s Brief You On Recent Developments For Electrostatic Motors

Over on his YouTube channel [Ryan Inis] has a video about how electrostatic motors are breaking all the rules.

He explains that these days most motors are electromagnetic but suggests that may be changing as the age-old principles of electrostatics are being explored again, particularly due to the limited supply of rare-earth magnets and other materials (such as copper and steel) which are used in many electromagnetic motors.

[Ryan] says that new electrostatic motors could be the answer for highly efficient and economical motors. Conventional electromagnetic motors pass current through copper windings which create magnetic fields which are forces which can turn a rotor. The rotor generally has permanent magnets attached which are moved by the changing magnetic forces. These electromagnetic motors typically use low voltage and high current.

Electrostatic alternatives are actually an older design, dating back to the 1740s with the work of Benjamin Franklin and Andrew Gordon. These electrostatic motors generate motion through the attraction and repulsion of high voltage electric charges and demand lower current than electromagnetic motors. The high voltages involved create practical problems for engineers who need to harness this energy safely without leading to shocks or sparks or such.

[Ryan] goes on to discuss particular electrostatic motor designs and how they can deliver higher torque with lower energy losses due to friction and heat making them desirable for various applications, particularly industrial applications which demand low speed and high torque. He explains the function of the rotor and stator and says that these types of motors use 90% less copper than their electromagnetic alternatives, also no electrical steel and no permanent magnets.

For more coverage on electrostatic motors check out Electrostatic Motors Are Making A Comeback.

Continue reading “Let’s Brief You On Recent Developments For Electrostatic Motors”

One-Motor Drone Mimics Maple Seeds For Stability

We’ve seen aircraft based on “helicopter” seeds (technically samara seeds, which include those of maples and elms) before, but this recent design from researchers at the Singapore University of Technology and Design (SUTD) shows how a single small motor can power a spinning monocopter capable of active directed flight, including hovering.

The monocopter is essentially an optimized wing shape with a single motor and propeller at one end. Hardware-wise it might be simple, but the tradeoff is higher complexity in other areas. Physical layout and balance are critical to performance, and software-wise controlling what is basically a wing spinning itself at high speed is a complex task. The payoff is highly-efficient flight in a package that self-stabilizes; it weighs only 32 grams and has a flight time of 26 minutes, which is very impressive for a self-contained micro aircraft.

We saw what looks like an earlier version of this concept from SUTD that was capable of directed flight by modifying the airfoil surface, but like the seeds it was modeled after, it’s more of a glider. This unit has the same spinning-seed design, but is actively powered. A significant improvement, for sure.

For those who prefer their DIY micro aircraft a little more traditional-looking, be sure to check out the design details of a handmade and fully operational 1:96 scale P-51 Mustang that weighs only 2.9 grams. It even has retractable landing gear! When one can manage to keep mass to a bare minimum, a little power goes a long way.

Carry Your Grayscale Memories With This Tiny Game Boy Photo Frame

While we cannot be certain this is the world’s smallest digital photo frame, [Raphaël Boichot]’s Pico Slide Show is probably in the running. Since the 0.85″ TFT display would be wasted on multi-megapixel images, [Raphael] has dedicated this project to images from the Game Boy Camera.

It’s a good fit: the tiny square display has a resolution of 128 pixels per side, while the Game Boy Camera produces files measuring 128 x 112. That allows for pixel-perfect rendering of the grainy images from everyone’s favorite early digicam with just a little letter boxing.

While perfect for all your on-the-go Game Boy slideshow needs, an enclosure might be a good idea for hauling around that battery.

The brains of the operation are an RP2040, provided via the RP2040-zero breakout from Waveshare. Since everything is through-hole or on breakouts, this wouldn’t be a bad project for a beginner solderer.

Since it would make no sense not to have this tiny unit to be portable, power is provided with a 503035 LiPo pouch on the back. It’s only 500 mAh, but this device isn’t going to be chugging power, so we’d expect a reasonable runtime.

Alas, no link cable functionality is currently included, and files must be transferred via PC. Images are saved to the Pico’s flash memory, and [Raphaël] says any format from any Game Boy Printer emulator will work, provided it has a four-color palette. The flash memory on the chip has room for 540 images, which seems like more than enough. Regardless of the novelty of the tiny screen and retro format, nobody wants to see that many holiday snaps in one go.

The Game Boy Camera has been popular with hackers literally for decades now, and we’ve seen it everywhere from wedding photo booths to the heart of a custom DSLR, and even on Zoom calls.

Hide Capacitive Touch Buttons In Your Next 3D Print

Capacitive touch sensors are entirely in the domain of DIY, requiring little more than a carefully-chosen conductive surface and a microcontroller. This led [John Phillips] to ask why not embed such touch buttons directly into a 3D print?

Button locations and labels can be made as part of the 3D print, which is handy.

The process is not much different from that of embedding hardware like magnets or fasteners into 3D prints: one pauses the print at convenient spot, drops in the necessary hardware, then resumes printing. It’s more or less the same for embedding a touch-sensitive button, but [John] has a few tips to make things easier.

[John] suggests using a strip of copper tape, one per touch pad, and embedding it into the print near the surface. His preference is three layers in, putting the copper tape behind 0.6 mm of plastic when using standard 0.20 mm layer heights.

Copper tape makes a good capacitive touch sensor, and the adhesive on the tape helps ensure it stays in place as the 3D printer seals it in on subsequent passes.

Copper tape is also easy to solder to, so [John] leaves a small hole over the copper — enough to stick in a wire and tack it down with the tip of a soldering iron and a blob of solder after the print is complete. It might not be ideal soldering conditions, but if things get a little melty on the back side it’s not the end of the world.

On the software side capacitive touch sensors can be as simple as using an Arduino library for the purpose but [John] rolled his own code, so give it a peek.

This reminds us a bit of another way to get a capacitive touch sensor right up against some plastic: a simple spring can do the trick.

Instant Macropad: Just Add QMK

I recently picked up one of those cheap macropads (and wrote about it, of course). It is surprisingly handy and quite inexpensive. But I felt bad about buying it. Something like that should be easy to build yourself. People build keyboards all the time now, and with a small number of keys, you don’t even have to scan a matrix. Just use an I/O pin per switch.

The macropad had some wacky software on it that, luckily, people have replaced with open-source alternatives. But if I were going to roll my own, it would be smart to use something like QMK, just like a big keyboard. But that made me wonder, how much trouble it would be to set up QMK for a simple project. Spoiler: It was pretty easy.

The Hardware

Simple badge or prototype macropad? Why not both?

Since I just wanted to experiment, I was tempted to jam some switches in a breadboard along with a Raspberry Pi Pico. But then I remembered the “simple badge” project I had up on a nearby shelf. It is simplicity itself: an RP2040-Plus (you could just use a regular Pi Pico) and a small add-on board with a switch “joystick,” four buttons, and a small display. You don’t really need the Plus for this project since, unlike the badge, it doesn’t need a battery. The USB cable will power the device and carry keyboard (or even mouse) commands back to the computer.

Practical? No. But it would be easy enough to wire up any kind of switches you like. I didn’t use the display, so there would be no reason to wire one up if you were trying to make a useful copy of this project.

Continue reading “Instant Macropad: Just Add QMK”

Building A Robotic Arm Without Breaking The Bank

There are probably at least as many ways to construct a robotic arm as there are uses for them. In the case of [Thomas Sanladerer] his primary requirement for the robotic arm was to support a digital camera, which apparently has to be capable of looking vaguely menacing in a completely casual manner. Meet Caroline, whose styling and color scheme is completely coincidental and does not promise yummy moist cake for anyone who is still alive after all experiments have been run.

Unlike typical robotic arms where each joint in the arm is directly driven by a stepper motor or similar, [Thomas] opted to use a linear rail that pushes or pulls the next section of the arm in a manner that’s reminiscent of the action by the opposing muscles in our mammalian appendages. This 3D printer-inspired design is pretty sturdy, but the steppers like to skip steps, so he is considering replacing them with brushless motors.

Beyond this, the rest of the robotic arm uses aluminium hollow stock, a lot of 3D printed sections and for the head a bunch of Waveshare ST3215 servos with internal magnetic encoder for angle control. One of these ~€35 ST3215s did cook itself during testing, which is somewhat worrying. Overall, total costs was a few hundred Euro, which for a nine-degree robotic arm like this isn’t too terrible.

Continue reading “Building A Robotic Arm Without Breaking The Bank”