Automated Weed Spraying Drone Needs No Human Intervention

November 11, 2024 by 4 Comments

Battling weeds can be expensive, labor intensive and use large amounts of chemicals. To help make this easier [NathanBuilds] has developed  V2 of his open-source drone weed spraying system, complete with automated battery swaps, herbicide refills, and an AI vision system for weed identification.

The drone has a 3D printed frame, doubling as a chemical reservoir. V1 used a off-the-shelf frame, with separate tank. Surprisingly, it doesn’t look like [Nathan] had issues with leaks between the layer lines. For autonomous missions, it uses ArduPilot running on a PixHawk, coupled with RTK GPS for cm-level accuracy and a LiDAR altimeter. [Nathan] demonstrated the system in a field where he is trying to eradicate invasive blackberry bushes while minimizing the effect on the native prairie grass. He uses a custom image classification model running on a Raspberry Pi Zero, which only switches on the sprayers when it sees blackberry bushes in the frame. The Raspberry Pi Global Shutter camera is used to get blur-free images.

At just 305×305 mm (1×1 ft), the drone has limited herbicide capacity, and we expect the flights to be fairly short. For the automated pit stops, the drone lands on a 6×8 ft pad, where a motorized capture system pulls the drone into the reload bay. Here a linear actuator pushes a new battery into the side of the drone while pushing the spend battery one out the other side. The battery unit is a normal LiPo battery in 3D-printed frame. The terminal are connected to copper wire and tape contacts on the outside the battery unit, which connect to matching contacts in the drone and charging receptacles. This means the battery can easily short if it touches a metal surface, but a minor redesign could solve this quickly. There are revolving receptacles on either side of the reload bay, which immediately start charging the battery when ejected from the drone.

Developing a fully integrated system like this is no small task, and it shows a lot of potential. It might look a little rough around the edges, but [Nathan] has released all the design files and detailed video tutorials for all the subsystems, so it’s ready for refinement.

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Thermoelectric Blaster Flings Ice Projectiles

November 11, 2024 by 37 Comments

Nerf blasters are fun and all, but flinging foam can get old. Picking it up again, even moreso. This blaster from [Concept Crafted Creations] gets around that annoying problem by shooting ice instead. 

The concept was to build a better water gun with longer range—and what better way to do that than by shooting ice instead? The blaster relies on a PVC air tank for propulsion—one of the most controversial design choices you can make if you read the comments around here. It’s charged by a small air compressor, and dumping the air is handled by a solenoid valve. So far, so simple.

What makes this blaster special is where it gets its ammunition from. The blaster uses a custom CNC-machined block from PCBway to act as a freeze chamber. Water enters an aluminum block, and is cooled by thermoelectric elements. Once the projectile has frozen inside the chamber, it’s stuck in place, so the chamber is then heated by a small heating element. This melts the projectile just enough to allow it to be fired.

It’s a complicated but ingenious way of building an ice blaster. It does pack some real punch, too. It shoots the ice projectiles hard enough to shatter wine glasses. That’s enough to tell us you don’t want to be aiming this thing at your pals in a friendly match of Capture the Flag. Stick to paintballs, perhaps. Video after the break. Continue reading “Thermoelectric Blaster Flings Ice Projectiles” →

Making A Unique Type Of Wind Gauge For Home Assistant Use

November 11, 2024 by 13 Comments

Sometimes, it’s nice to know how windy it is outside. Knowing the direction of the wind can be a plus, too. To that end, [Sebastian Sokołowski] built himself an unusual anemometer—a wind gauge—to feed into his smart home system.

[Sebastian’s] build is able to tell both wind speed and direction—and with no moving parts! Sort of, anyway. That makes the design altogether different from the usual cup type anemometers with wind vanes that you might be used to seeing on home weather stations. [Sebastian] wanted to go a different route—he wanted a sensor that wouldn’t be so subject to physical wear over time.

The build relies on strain gauges. Basically, [Sebastian] 3D printed a sail-like structure that will flex under the influence of the wind. With multiple strain gauges mounted on the structure, it’s possible to determine the strength of the wind making it flex and in what direction. [Sebastian] explains how this is achieved, particularly involving the way the device compensates for typical expansion and contraction due to temperature changes.

It’s a really unique way to measure wind speed and direction; we’d love to learn more about how it performs in terms of precision, accuracy, and longevity—particularly with regards to regular mechanical and ultrasonic designs. We’ll be keeping a close eye on [Sebastian’s] work going forward. Video after the break.

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Retrogadgets: Oscilloscope Cameras

November 11, 2024 by 23 Comments

Today, if you want to get a picture from your oscilloscope — maybe to send to a collaborator or to stick in a document or blog post — it is super easy. You can push an image to a USB stick or sometimes even just use the scope’s PC or web interface to save the picture directly to your computer. Of course, if it is on the computer, you could use normal screen capture software. But that hasn’t always been the case. Back in the days when scopes were heavy and expensive, if you wanted to capture an image from the tube, you took a picture. While you might be able to hold up your camera to the screen, they made specific cameras just for this purpose.

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The 1987 Videonics Editing System

Videonics: The Dawn Of Home Video Editing, Revisited

November 11, 2024 by 3 Comments

Here’s a slice of history that will make any retro-tech fan grin: before TikTok and iMovie, there was a beast called the Videonics DirectED Plus. This early attempt at democratizing video editing saved enthusiasts from six-figure pro setups—but only barely. Popular Science recently brought this retro marvel back to life in a video made using the very system that inspired it. Picture it: 1987, VHS at its peak, where editing your kid’s jazz recital video required not just love but the patience of a saint, eight VCRs, three Videonics units, two camcorders, and enough remotes to operate a space shuttle.

The Videonics DirectED Plus held promise with a twist. It offered a way to bypass monstrous editing rigs, yet mastering its panel of buttons felt like deciphering hieroglyphs. The ‘Getting Started’ tape was the analog era’s lifeline, often missing and leaving owners hunting through second-hand stores, forgotten basements, and enthusiast forums. Fast forward to today, and recreating this rig isn’t just retro fever—it’s a scavenger hunt.

The 1987 Videonics Editing SystemOnce assembled, the system resembled a spaghetti junction of cables and clunky commands. One wrong button press could erase precious minutes of hard-won footage. Still, the determination of DIY pioneers drove the machine’s success, setting the stage for the plug-and-play ease we now take for granted.

These adventures into retro tech remind us of the grit behind today’s seamless content creation. Curious for more? Watch the full journey by Popular Science here.

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Illustrated Kristina with an IBM Model M keyboard floating between her hands.

Keebin’ With Kristina: The One With All The Espionage

November 11, 2024 by 6 Comments

[Ziddy Makes] describes this cute little guy as a biblically-accurate keyboard. For the unfamiliar, that’s a reference to biblically-accurate angels, which have wings (and sometimes eyes) all over the place. They’re usually pretty scary to behold. Don’t say I didn’t warn you.

A cube keyboard with adorably vibrant pastel keycaps.
Image by [Ziddy Makes] via GitHub
But this? This is the opposite of scary. Sure, there are keys everywhere. But it’s just so darn adorable. You know what? It’s those keycaps.

This 16-key macro cube uses a Pro Micro and a system of PH2 5p ribbon cables to connect the four four-key sisterboards to the main board. A 3D-printed base holds all the boards in place. Out of all the switches in the world, [Ziddy] chose Otemu Blues. Clack!

Although it may take some getting used to, this seems like it would be a fun way to input macros. I can see the case for putting some rubber feet on the bottom, otherwise it might scoot around on the desk. That might be cute, but only the first couple of times, you know?

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The Constant Monitoring And Work That Goes Into JWST’s Optics

November 11, 2024 by No comments

The James Webb Space Telescope’s array of eighteen hexagonal mirrors went through an intricate (and lengthy) alignment and calibration process before it could begin its mission — but the process is far from being a one-and-done. Keeping the telescope aligned and performing optimally requires constant work from its own team dedicated to the purpose.

Alignment of the optical elements in JWST are so fine, and the tool is so sensitive, that even small temperature variations have an effect on results. For about twenty minutes every other day, the monitoring program uses a set of lenses that intentionally de-focus images of stars by a known amount. These distortions contain measurable features that the team uses to build a profile of changes over time. Each of the mirror segments is also checked by being imaged selfie-style every three months.

This work and maintenance plan pays off. The team has made over 25 corrections since its mission began, and JWST’s optics continue to exceed specifications. The increased performance has direct payoffs in that better data can be gathered from faint celestial objects.

JWST was fantastically ambitious and is extremely successful, and as a science instrument it is jam-packed with amazing bits, not least of which are the actuators responsible for adjusting the mirrors.