The Minimum Required For A Film Camera

November 30, 2023 by Jenny List 13 Comments

Film cameras can be complex and exquisitely-crafted masterpieces of analogue technology. But at their very simplest they need be little more than a light-proof box with a piece of film at the back of it, and some kind of lens or pinhole with a shutter. [ChickenCrimpy] adds the most basic of 35 mm cartridge to create what he calls the Minimum Viable Camera. It’s a half-frame 35 mm pinhole film camera with the simplest possible construction.

It can be built from almost any flat light-proof 3 mm thick stock, though something that you can run through a laser cutter is probably ideal. Once snapped together to make to box-like structure, tape is added along the joins for light-proofing. The film is reeled from a full 35 mm cartridge to an empty one, and cranked back frame-by-frame by means of a wooden key that engages with the spindle.

There’s no lens, instead this is a pinhole camera, and the shutter is a piece of the stock held on the front of the camera with bolts and butterfly nuts. Taking a photo is as simple as pointing the device at the subject and lifting the shutter away for a few seconds. There’s a video overview for the project which we’ve placed below the break.

It’s true that this camera needs a moment in the darkroom to load, but we like its extreme simplicity and the ethereal and grainy pictures it produces. If you fancy an introduction to 35 mm photography you could definitely do worse.

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End Of An Era: Popular Science Shutters Magazine

November 30, 2023 by Tom Nardi 69 Comments

Just three years after the iconic magazine abandoned its print version and went all-digital, Popular Science is now halting its subscription service entirely. The brand itself will live on — their site will still run tech stories and news articles, and they have two podcasts that will keep getting new episodes — but no more quarterly releases. While you can’t complain too much about a 151 year run, it’s still sad to see what was once such an influential publication slowly become just another cog in the content mill.

Started as a monthly magazine all the way back in 1872, Popular Science offered a hopeful vision of what was over the horizon. It didn’t present a fanciful version of what the next 100 years would look like, but rather, tried to read the tea leaves of cutting edge technology to offer a glimpse of what the next decade or so might hold. Flip through a few issues from the 1950s and 60s, and you won’t see pulpy stories about humanity conquering the stars or building a time machine. Instead the editors got readers ready for a day when they’d drive cars with warbird-derived turbochargers, and enjoy more powerful tools once transistor technology allowed for widespread use of small brushless motors. It wasn’t just armchair engineering either, issues would often include articles written by the engineers and researchers that were on the front lines. Continue reading “End Of An Era: Popular Science Shutters Magazine” →

Autonomous Excavator Builds Stone Wall Algorithmically

November 30, 2023 by Kristina Panos 21 Comments

In a move that aims to further the circular economy of the construction industry, researchers at ETH Zurich have let an autonomous excavator loose on a big pile of boulders and reclaimed concrete. The goal? To build a 20 foot (6 meter) and 213 ft (65 m) long dry-stone wall as part of a park where the landscape was digitally planned, and the earth autonomously excavated.

The coolest thing about the Menzi Muck excavator is the software, which is explored in the video after the break. Thanks to a bunch of sensors, the excavator can not only draw a 3D map of the site, it can find in situ boulders dotting the landscape and incorporate them into the wall.

Machine vision allows the excavator to grab the stones and assess their size and shape, as well as approximate their weight and center of gravity.

Then, an algorithm determines the best place for each stone and places them there without using mortar or cement. Menzi Muck is capable of number-crunching 20 to 30 stones at a time, which coincidentally is about the number in one delivery.

Want to build your own excavator? Check out this finely-detailed R/C excavator for top-notch inspiration.

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Falsified Photos: Fooling Adobe’s Cryptographically-Signed Metadata

November 30, 2023 by Adam Zeloof 34 Comments

Last week, we wrote about the Leica M11-P, the world’s first camera with Adobe’s Content Authenticity Initiative (CAI) credentials baked into every shot. Essentially, each file is signed with Leica’s encryption key such that any changes to the image, whether edits to the photo itself or the metadata, are tracked. The goal is to not only prove ownership, but that photos are real — not tampered with or AI-generated. At least, that’s the main selling point.

Although the CAI has been around since 2019, it’s adoption is far from widespread. Only a handful of programs support it, although this list includes Photoshop, and its unlikely anybody outside the professional photography space was aware of it until recently. This isn’t too surprising, as it really isn’t relevant to the casual shooter — when I take a shot to upload to Instagram, I’m rarely thinking about whether or not I’ll need cryptographic proof that the photo wasn’t edited — usually adding #nofilter to the description is enough. Where the CAI is supposed to shine, however, is in the world of photojournalism. The idea is that a photographer can capture an image that is signed at the time of creation and maintains a tamper-proof log of any edits made. When the final image is sold to a news publisher or viewed by a reader online, they are able to view that data.

At this point, there are two thoughts you might have (or, at least, there are two thoughts I had upon learning about the CAI)

Do I care that a photo is cryptographically signed?
This sounds easy to break.

Well, after some messing around with the CAI tools, I have some answers for you.

No, you don’t.
Yes, it is.

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300 Amps Through An Open Source Speed Controller

November 30, 2023 by Lewin Day 23 Comments

Sometimes, a little puny matchbox-sized electronic speed controller (ESC) won’t do the job. If you find yourself looking for something heftier, say, in the range of hundreds of amps, you might look towards a design like the MP2 ESC. [owhite] has built an example of the design that can deliver some serious power.

[owhite’s] build has some serious specs: it’s rated to offer up to 300 amps at up to 150 volts, though thus far, it’s only been tested at up to 100 V. Like the original MP2, which hails from the Endless Sphere forums, it’s designed to be compatible with VESC code using the STM32F405 microcontroller. It’s intended for driving high-powered traction motors in applications like e-bikes and electric scooters, as you might have guessed by its potential output power being well into the tens of kilowatts range.

If you’re eager to build your own, you can do so, with the design files on GitHub. Just note that you’ll need some hefty parts to handle the juice, including beefy MOSFETS and juicy capacitors rated at 160 V.

Open source motor controllers abound of late, and we’ve featured a few in recent times. Just remember that astute design and using parts within their means is the key to avoiding letting the smoke out! Continue reading “300 Amps Through An Open Source Speed Controller” →

Open Source Spacecraft Avionics With NASA’s Core Flight System

November 30, 2023 by Maya Posch 18 Comments

One thing about developing satellites, spacecraft, rovers and kin is that they have a big overlap in terms of functionality. From communication, to handling sensors, propulsion, managing data storage, task scheduling and so on, the teams over at NASA have found over the years that with each project there was a lot of repetition.

Block diagram of a simplified avionics system. (Credit: NASA)

Either they were either copy-pasting code from old projects, or multiple teams were essentially writing the same code.

To resolve this inefficiency NASA developed the Core Flight System (cFS), a common software framework for spacecraft, based on code and lessons from various space missions. The framework, which the space agency has released under the Apache license, consists of an operating system abstraction layer (OSAL), the underlying OS (VxWorks, FreeRTOS, RTEMS, POSIX, etc.), and the applications that run on top of the OSAL alongside the Core Flight Executive (cFE) component. Here cFS apps can be loaded and unloaded dynamically, along with cFS libraries, as cFS supports both static and dynamic linking.

There are a few sample applications to get started with, and documentation is available, should you wish to use cFS for your own projects. Admittedly, it’s a more complex framework than you’d need for a backyard rover. But who knows? As access to space gets cheaper and cheaper, you might actually get the chance to put together a DIY CubeSat someday — might as well start practicing now.

Gesture-Controlled Robot Arm Is A Nifty Educational Build

November 29, 2023 by Lewin Day 2 Comments

Traditionally, robot arms have been controlled either by joysticks, buttons, or very carefully programmed routines. However, for [Narongporn Laosrisin’s] homebrew build, they decided to go with gesture control instead.

The MeArm robotic arm is built using laser cut acrylic parts, and can be had in a kit if so desired. It features four servo motors, charged with rotating the arm’s base, pushing the arm forwards and backwards, up and down, and actuating its gripper. The servos are under the command of a micro:bit microcontroller board, which itself receives signals from a second micro:bit which is strapped to the human wishing to control the arm. The second micro:bit detects gestures with its accelerometer, and then sends the relevant commands to the robotic arm’s micro:bit over its built-in radio link. The arm controller then commands the servos to execute the maneuver.

It may be a small robotic arm that doesn’t have the capacity to lift much, but that’s not the point. This project is a great way to teach students how to program microcontrollers, work with sensor inputs, and just generally how to solve engineering puzzles. To that end, it looks like [Narongporn] has a great project on hand for teaching their students. Video after the break.

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