Author: Danie Conradie

425 Articles

3D Printing Bores Without Support

May 28, 2023 by 14 Comments

If you’ve done even a small amount of 3D printing, you probably ran into the challenge of printing a small hole on top of a larger hole. The conventional solution is just to add support, but in the video after the break, [Angus] of Maker’s Muse demonstrates an alternative solution you can implement in CAD, without having to do manual post-processing.

This is a common problem when you have a countersink feature for a bolt head or captured nut on the bottom of the part. [Angus] first demonstrates some other techniques, including printing the bore over empty space, adding a sacrificial bridge, and making the overhang 45°. Each of these work but have some trade-offs. The proposed solution is what [Angus] calls sequential overhangs. It involves bridging the sides of the open space in steps to create supporting edges onto which the bore perimeter can print. It starts with 2 or 3 bridging layers to create a rectangle the same width as the bore, and then a second set of bridges at 90° to turn the opening into a square. For smaller holes this should create enough of a support to start the bore perimeter, but for larger holes three sets of bridges at 60° offsets might be needed.

[Angus] does not claim to have invented the technique but states he borrowed the idea from parts printed by Prusa Research for their popular line of 3D printers. One of the comments on the [Maker’s Muse] video referenced a 2014 blog post by [nophead] showing the same approach. Regardless of the idea’s lineage, it’s a great addition to anyone’s 3D printing design toolbox.
Continue reading “3D Printing Bores Without Support” →

Gyroscope Walks The Tightrope

May 23, 2023 by 13 Comments

Gyroscopes are one of those physics phenomena that are a means to many ends, but can also enjoyed as a fascinating object in their own right. Case and point being [Hyperspace Pirate]’s tightrope-balancing crawler in the video after the break.

Inside the PLA and aluminum shell is a 3D-printed wheel with steel bolts around the edge for added moment of inertia. It is powered by a low-KV brushless motor with a 3:1 GT2 belt-drive and controlled by a simple servo tester, running on a 4 cell LiPo battery. The 3D-printed drive wheel is powered by a geared DC motor hooked directly to the battery. [Hyperspace Pirate] goes over the math of the design, showing that path to stability is a high speed and high moment of inertia flywheel, while staying well within the strength limits of the wheel’s material.

It’s balancing act was first demonstrated on a length of PVC conduit and then on a section of rope, with the characteristic circular wobbling of a gyroscope, known as gyroscopic precession. Without active correction, this the angle of procession will steadily increase until the machine falls over. Even so, it’s still great to watch a small scale version, like the one that inspired this build, would make a pretty cool desk toy.

Gyroscopes are commonly used in attitude indicators and and heading indicators in aircraft, and we’ve also seen them get used for balancing robots. Any ideas for practical uses for a mono-wheel rail/rope walker? Drop them in the comments below.

Continue reading “Gyroscope Walks The Tightrope” →

Pill Dispenser To Keep You On Track

May 21, 2023 by 11 Comments

When forgetting to take medication on time can lead to a bad day or night, having a helper to keep you on track can greatly improve your life. [M. Bindhammer] faces this scenario every day, so he built his own robotic pill dispenser.

The core of the project is a 3D printed dispensing drum with individual pockets for morning and evening medication. It is mounted directly to a 360° winch servo, normally used for RC sailboats, while a second conventional servo opens a small sliding door to drop the pills onto the dispensing tray. The tray integrates a sensitive touch sensor which can detect when [M] picks up the pills, without being triggered by the pills themselves.

[M. Bindhammer] also included a small but loud speaker, connected to a speech synthesis module for audio reminders. The main controller is a Arduino Due with a custom breakout shield that also integrates a DS3231 real time clock. All the electronics are enclosed in a 80’s style humanoid robot-shaped body, with dispensing drum on its chest, and an OLED screen as it’s face.

The end result is a very polished build, which should make [M. Bindhammer]’s life with bipolar disorder a little bit easier, and he hopes it might help others as well.

For more medication related gadgets, take a peek at another pill dispenser and a 3D printed dosing spoon to replace an essential but discontinued commercial version.

THOR Microwaves Drone Swarms

May 20, 2023 by 39 Comments

In recent years small drones have gone from being toys and photography tools to a deadly threat on the battlefield. Kamikaze drones have become especially prominent in the news due to their use in the war in Ukraine by both sides. While we haven’t seen coordinated swarms being actively employed on the modern battlefield, it’s likely only a matter of time, making drone swarm defense an active field of development in the industry.

The US Air Force Research Laboratory recently conducted tests and a demonstration of an anti-drone weapon that uses pulses of high-power microwave energy to fry the electronics of a swarm of drones. Named the Tactical High-power Operational Responder, or THOR  (presumably they picked the acronym first), it’s housed in a 20ft shipping container with large microwave antenna on top. The form factor is important because a weapon is only useful if it can reach the battlefield, and this can fit in the back of a C130.

THOR likely functions similarly to a shotgun, with a relatively large effective “beam.” This would have added advantages like frying multiple drones with one pulse and not needing pinpoint tracking and aiming tech required for projectile and laser-based weapons. Depending on its range and directivity, THOR might come with the downside of collateral damage to electronics close to its line of fire.

Drone swarms are of course the other side of this arms race, but fortunately they also have non-destructive uses like lights shows and perhaps even 3D printing.

An Elegant Solution For Smart Home Device Integration

May 20, 2023 by 49 Comments

Integrating non-smart devices into your home automation system can be a cumbersome process, involving the wiring of multiple modules. However, [Pricelesstoolkit] has created the ESPClicker — a compact, ESP8266-based module that can remotely “press buttons” and simplify this process.

The ESPClicker’s core feature is its three relays that can be soldered to the button terminals of any existing “dumb” device, as [Pricelesstoolkit] demonstrated with his coffee machine in the video after the break. One of the relays can also be configured in the normally closed configuration. A compact twelve pin connector provides a removable wiring interface for the buttons, additional relays, power and even a contactless power detector that can be wrapped around an AC wire.

[PricelessToolkit] has done several Home Assistant related projects, and we recently featured his little Home Assistant controlled guardian bot. We’ve also seen other project that make use of ESPHome, like a iPod style scroll wheel and a LEGO train set.

Continue reading “An Elegant Solution For Smart Home Device Integration” →

Go In All The Directions With Omniwheeled ESP32 Bot

May 18, 2023 by 18 Comments

The ability to change direction without turning is the specialty of omnidirectional wheels, which [maker.moekoe] used to their full potential on a pair of ESP32-controlled robots. Video after the break.

Thanks to the rollers on the wheels, the wheels could be arranged at 120° in relation to each other on the 3-wheeler and 90° 4-wheeler. [maker.moekoe] used ChatGPT and a simple python simulation to find and verify the motor control algorithm required for smooth omnidirectional driving.

A single custom PCB incorporates all the electronics, and doubles as the robot’s chassis, with the geared brushed motors bolted directly to it. An ESP32-S2 runs the show, and can also stream FPV video from the same OV2640 camera used on the popular ESP32-cam modules. The LiPo battery is held by a 3D-printed support plate screws to the bottom of the PCB. The robots can controlled by a simple web-app served by the ESP32, or a using the IMU on custom controller also built around an ESP32-S2 which uses the ESP-NOW wireless protocol.

Even though the robots’ software is still in the early stages, the movement looks extremely smooth and effortless. Plus, their all-in-one PCB chassis makes for an elegant and clean build

Continue reading “Go In All The Directions With Omniwheeled ESP32 Bot” →

Active Racing Simulator Pedal

May 17, 2023 by 11 Comments

Racing virtual cars from behind a PC monitor might be cheaper than doing it in the real world, but high-end sim racing peripherals still come with high-end prices. With the increasing popularity of force-feedback pedals [Tristan Fenwick] built built an active pedal that can provide significant resistance.

[Tristan] integrated a load cell into the 3D printed pedal linkage, which is connected to a 130 W NEMA23 servo motor via a 8 mm lead screw. With constant feedback from the load cell, a simple PID controller running on an Arduino to actively adjust the pedal’s position and the amount of resistance it provides.

At ~$250 in parts, it’s a significantly more affordable than the $2300 price tag on a single Simucube pedal, which served as inspiration for this project. There are still some issues to address, such as shaky ADC readings and a lack of computing power on the Arduino, the demo video after the break looks incredibly promising. [Tristan] also notes that 300 kg is overkill and a slightly smaller servo motor would probably also work.

For more incredible simulator inspiration, check out the A-10 Warthog cockpit, a 3D printed flight sim yoke and pedals, and a tank driving simulator from before the age of computer graphics.

Continue reading “Active Racing Simulator Pedal” →