Linux Cell Phone? Build OURPhone

May 5, 2023 by Al Williams 30 Comments

[Evan] couldn’t find a phone he liked, so he decided to build his own. There are advantages and disadvantages, as you might expect. On the plus side, you have the ultimate control. On the negative side, it doesn’t quite have the curb appeal — at least to the average user — of a sleek new cell phone from a major manufacturer.

The phone uses a Raspberry Pi, along with a 4G modem and a 480×800 touchscreen. There’s a laser cut box that measures 90x160x30 mm. For reference, a Google Pixel 7 is about 73x156x9 mm, so a little easier on the pocket.

But not one the pocketbook. The OURPhone only costs about $200 USD to build. There are trade-offs. For example, the touchscreen is resistive, so you’ll want a stylus (there’s a slot for it in the case). On the other hand, if you don’t like something, it is all there for you to change.

Obviously, a better screen would help. Thinner batteries might be a good enhancement too. But that’s the beauty of an open project. You can do all these things and more.

We wondered if you could get one of the “mobile” Linux editions to run or even Android. It seems like the hardest part is coming up with a sophisticated enclosure.

CNC Feeds And Speeds, Explained As A First-Timer

May 5, 2023 by Donald Papp 35 Comments

If you’ve ever looked into CNC cutting tools, you’ve probably heard the term “feeds and speeds”. It refers to choosing the speed at which to spin the cutting tool, and how fast to plow it into the material being cut. They’re important to get right, and some of the reasons aren’t obvious. This led [Callan Bryant] to share his learned insights as a first-timer. It turns out there are excellent (and somewhat non-intuitive) reasons not to simply guess at the correct values!

A table of variables and how they relate to one another (click to enlarge).

The image above shows a tool damaged by overheating. [Callan] points out that as a novice, one might be inclined to approach a first cutting jobs conservatively, with a low feed rate. But doing this can have an unexpected consequence: a tool that overheats due to spinning too quickly while removing too little material.

CNC cutting creates a lot of heat from friction, and one way to remove that heat is by having the tool produce shavings, which help carry heat away. If a tool is making dust instead of shavings — for example if the feed rate is too conservative — the removed pieces will be too small to carry significant energy, and the tool can overheat.

[Callan] makes a table of variables at work in a CNC system in order to better understand their relationship before getting into making a formula for calculating reasonable feed and speed rates. Of course, such calculations are a reasonable starting point only, and it’s up to the operator to ensure things are happening as they should for any given situation. As our own Elliot Williams observed, CNC milling is a much more manual process than one might think.

NVIDIA Jetson Powers Real-Time Iron Man HUD

May 4, 2023 by Tom Nardi 15 Comments

If you could recreate any of the capabilities of Tony Stark’s Iron Man suit in real life, it would probably be the ability to fly, the super strength, or maybe even the palm-mounted lasers that can cut through whatever obstacle is in your path. But let’s be real, all that stuff is way too hard to try and pull off. Plus you’ll probably just end up accidentally killing yourself in the backyard.

But judging by the videos he’s been posting, [Kris Kersey] is doing one hell of a job creating a functional heads-up display (HUD) similar to the one Tony uses in the films. He’s even building it into a 3D printed Iron Man helmet, with the NVIDIA Jetson board that’s powering the show inside a chest-mounted “Arc Reactor”. He goes into a bit more detail about the project and his goals in an interview recently published on NVIDIA’s own blog. Continue reading “NVIDIA Jetson Powers Real-Time Iron Man HUD” →

Hacking Hue Lightbulbs

May 4, 2023 by Al Williams 13 Comments

What do you do with a Hue smart lightbulb? Well, if you are [Chris Greening], you take it apart and get hacking. If you ever wondered what’s inside, the teardown is pretty good, and you can also watch the video below. The potting compound, however, makes a mess.

Once you get the potting undone, there are three PCBs: an LED carrier, a power supply, and a logic board. The arrangement of the LEDs is a bit confusing, but [Chris] explains it along with providing schematics for all of the boards.

Continue reading “Hacking Hue Lightbulbs” →

Easter’s Over, But You Can Still Dye Keycaps

May 4, 2023 by Kristina Panos 11 Comments

While it’s true that keycap colorways abound these days, one can’t always find exactly what one is looking for. And once found, the set is often either prohibitively expensive, or it doesn’t come in the desired layout, or both. So, why not color your own keycaps?

That’s exactly what [amphiboi] did, while standing on the shoulders of [CrowningKnight]’s imgur post on the subject. Essentially, you use Rit dye and PBT keycaps for best results. Rit has a comprehensive guide to mixing their dyes to achieve pretty much whatever colors you want. Once that’s all squared away, it’s time to gather your cooking supplies.

Starting with a pot you don’t care about and four cups of boiling water. Add about a teaspoon of dish soap, which helps the dye settle evenly across the keycaps. Then you just add the dye(s) and stir with an expendable spoon, then add your keycaps. 5-10 minutes later, depending on your desired outcome, the ‘caps are ready to be rinsed, dried, and pushed on to your switches.

Satisfied with the color of your keycaps, but wish they had cool legends? Check out this waterslide decal tutorial.

ChatGPT Makes A 3D Model: The Secret Ingredient? Much Patience

May 4, 2023 by Donald Papp 44 Comments

ChatGPT is an AI large language model (LLM) which specializes in conversation. While using it, [Gil Meiri] discovered that one way to create models in FreeCAD is with Python scripting, and ChatGPT could be encouraged to create a 3D model of a plane in FreeCAD by expressing the model as a script. The result is just a basic plane shape, and it certainly took a lot of guidance on [Gil]’s part to make it happen, but it’s not bad for a tool that can’t see what it is doing.

The first step was getting ChatGPT to create code for a 10 mm cube, and plug that in FreeCAD to see the results. After that basic workflow was shown to work, [Gil] asked it to create a simple airplane shape. The resulting code had objects for wing, fuselage, and tail, but that’s about all that could be said because the result was almost — but not quite — completely unlike a plane. Not an encouraging start, but at least the basic building blocks were there. Continue reading “ChatGPT Makes A 3D Model: The Secret Ingredient? Much Patience” →

Op-Amp Challenge: Get More From A Single Wire With An Analogue Adder

May 4, 2023 by Jenny List 10 Comments

It’s been a running battle in some quarters for years, whether analog sensor processing is better than digital. Proponents of digital are sometimes driven by lack of familiarity with analog circuitry, while analog die-hards point to delays and software crashes in microcontrollers. We’d probably toe the line that a mixture of the two skills is best, but [paul] has gone full-on for the analog side with his position and limit sensor for a remote telescope. The ‘scope had only one control wire carrying a digital signal, so how was he to get extra information down it? The solution was to overlay a DC voltage, and use a summing network composed of a series of op-amps to encode position and limit data as voltage.

In operation, the circuit is a straightforward DC summing amplifier of the type that op-amps were designed for and at which they excel. We’re not so sure it needs the high-precision resistors and the choice of op-amps seems the wrong way round with the AD8532’s high current output being better suited to driving the line than straightforward summing, but we can see it does the job. If you’re after a demonstration of a DC summing amplifier using an op-amp, here’s your project. Meanwhile if you’re curious about an op-amp inside the black box, take a look at one of the simplest integrated circuit op-amps ever made.