Open Source Scanner Scans The Slides

December 26, 2023 by 9 Comments

What do you get when you join a slide projector and a digital camera? Filmolimo, an open source slide scanner. The scanner uses an M5Stack Fire, an ESP32 development board. Thanks to the ESP32, you can control the device via WiFi.

All the project files, including KiCAD design files, are on GitHub. Of course, you will probably have to adapt things to your specific camera and slide projector. The PCB is double-sided and looks easy to put together. The board is mostly opto-isolation and interface between the controller and the equipment. The software allows you to change things like the time between slides, for example.

This is one of those projects you probably only need for a bit. Unless, of course, you regularly scan slides. You can farm it out to a service provider, but what fun is that? If you have a few hundred thousand slides, you might need to go for speed. If you just have a few, you can get by with a simple adapter.

Open Source DC UPS Keeps The Low-Voltage Gear Going

December 22, 2023 by 27 Comments

We all like to keep our network gear running during a power outage — trouble is, your standard consumer-grade uninterruptible power supply (UPS) tends to be overkill for routers and such. Their outlet strips built quickly get crowded with wall-warts, and why bother converting from DC to AC only to convert back again?

This common conundrum is the inspiration for [Walker]’s DC UPS design, which has some interesting features. First off, the design is open source, which of course invites tinkering and repurposing. The UPS is built for a 12 volt supply and load, but that obviously can be changed to suit your needs. The battery bank is a 4S3P design using 18650 cells, and that could be customized as well. There’s an ideal diode controller that prevents DC from back-feeding into the supply when the lights go out, and a really interesting synchronous buck-boost converter in place of the power management chip you’d normally see in a UPS. The converter chip takes a PWM signal from an RP2040; there’s also an ESP32 onboard for web server and UI duties as well as an STM32 to run the BMS. The video below discusses the design and shows a little of the build.

We’ve seen a spate of DC UPS designs lately, some more elaborate than others. This one has quite a few interesting chips that most of us don’t normally deal with, and it’s nice to see how they’re used in a practical design.

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Make Carbon Fiber Tubes With An Open Source Filament Winder

December 11, 2023 by 21 Comments
Result of winding a carbon fiber tube. (Credit: Andrew Reilley)

Carbon fiber (CF) is an amazing material that provides a lot of strength for very little weight, making it very useful for a lot of applications, ranging from rods in CoreXY 3D printers to model- and full-sized rockets. The model rocketry hobby is the reason why [Andrew Reilley] developed his own CF tube winding machine called Contraption. A tutorial video (also embedded below) shows how this machine is prepped for a winding run, followed by the winding progress and finalizing before admiring the result.

The entire machine’s design with 3D printed parts and off-the-shelf components is open source, as is the TypeScript and NodeJS-based Cyclone software that creates the toolpath specifying the parameters of the tube, including number of layers and the tow angle.

As a wet winding tow machine, the carbon fiber strands are led through the liquid resin before being wound onto the prepared mandrel. During winding some excess resin may have to be removed, and after the winding has been finished the tube is wound with shrink tape. This is followed by a heat gun session to shrink the tape and letting the resin cure. Following curing, the tape and mandrel are removed, resulting in a rather fancy looking CF tube that can find a loving home in a lot of applications, except perhaps ones that involving crushing outside pressures like those found deep below the ocean surface.

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300 Amps Through An Open Source Speed Controller

November 30, 2023 by 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 17 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)
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.

Tesla Claims To Have Open Sourced The Roadster

November 25, 2023 by 38 Comments

In an interesting step for anyone who follows electric car technology, the automaker Tesla has released a trove of information about its first-generation Roadster car into the public domain. The documents involved include service manuals, circuit diagrams, and technical details, and Elon Musk himself Tweeted posted on X that “All design & engineering of the original @Tesla Roadster is now fully open source.”

We like the idea and there’s plenty of interesting stuff there, but we can’t find an open-source licence anywhere and we have to take issue with his “Whatever we have, you now have” comment. What we have is useful maintenance information and presents a valuable window into 2010’s cutting edge of electric vehicles, but if it’s everything they have then something must have gone very wrong in the Tesla archives. It’s possible someone might take a Lotus Elise and produce something close to a Roadster replica with this info, but it’s by no means enough to make a car from. Instead we’re guessing it may be a prelude to reducing support for what is a low-production car from over a decade ago.

When it comes to electric vehicle manufacturers open-sourcing their older models we already have a model in the form of Renault’s open-source version of their Twizy runabout. This is a far more credible set of information that can be used to make a fully open-source version of the car, rather than a set of workshop manuals.

Tesla Roadster, cytech, CC BY 2.0.

Drone Motion Capture, The Open Source Way

November 23, 2023 by 4 Comments

If you want to do some really advanced flying with drones, you typically need to be able to track them in space. [Joshua Bird] has whipped up a drone tracking system that can do the job for as little as $20 with millimeter-scale precision.

The system uses four PS3 Eye cameras which can be had second-hand at a cost of just $5 each. They’re modified by removing their IR cut filter, and putting in an IR-passing filter in the form of a cut-up slice of floppy disk. The system tracks the drones via their infrared indicators and the known locations of the four cameras themselves, which the system is capable of mapping out automatically. By using four cameras, the system is robust in the event the view of a camera is occluded. The system can track multiple drones at the same time, with [Joshua] demonstrating it working with two drones each carrying three infrared markers. He has the system set up to send positional updates to ESP32 microcontrollers on the drones themselves, which command the drones to hold them in set positions.

Code is available on GitHub for the curious. We’ve seen other similar work before, too.

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