Paint The Rainbow With This Skittle-Dropping Pixel Art Robot

July 12, 2019 by Dan Maloney 7 Comments

We hackers just can’t get enough of sorters for confections like Skittles and M&Ms, the latter clearly being the superior candy in terms of both sorting and snackability. Sorting isn’t just about taking a hopper of every color and making neat monochromatic piles, though. [JohnO3] noticed that all those colorful candies would make dandy pixel art, so he built a bot to build up images a Skittle at a time.

Dubbed the “Pixel8R” after the eight colors in a regulation bag of Skittles, the machine is a largish affair with hoppers for each color up top and a “canvas” below with Skittle-sized channels and a clear acrylic cover. The hoppers each have a rotating disc with a hole to meter a single Skittle at a time into a funnel which is connected to a tube that moves along the top of the canvas one column at a time. [JohnO3] has developed a software toolchain to go from image files to Skittles using GIMP and a Python script, and the image builds up a row at a time until 2,760 Skittle-pixels have been placed.

The downside: sorting the Skittles into the hoppers. [JohnO3] does this manually now, but we’d love to see a sorter like this one sitting up above the hoppers. Or, he could switch to M&Ms and order single color bags. But where’s the fun in that?

[via r/arduino]

Preserving Precious Laptop Stickers

July 12, 2019 by Brian Benchoff 75 Comments

Stickers belong on laptops. That’s not just because all developers are issued a 2015 MacBook Pro at birth to zealously hold and cherish for the rest of their careers, and the vast uniformity of laptop models in the workplace makes each individual’s laptop indistinguishable from anyone else’s. No, stickers belong on laptops because that ‘RUN GCC’ sticker is just so good. But how do you keep a laptop stickered up while not hurting the resale value or worrying about sticky residue left behind? That’s the question [Graham] answered, and the answer may surprise you.

The problem is such: there mus be a way to apply stickers to a MacBook that is invisible, removable, and leaves no trace after being removed, even after years of enjoying a bestickerd’ laptop. The first thought turned to old-style screen protectors for a phone, but this had problems: they’re glossy, and sourcing a large sheet of screen protectors proved difficult.

After some research, it turned out there was a market with similar requirements: car wraps. Yes, you can wrap your car in vinyl that’s any color you want, including whatever Apple is calling their plain aluminum finish these days. As far as a protector for an aluminum MacBook, it looks good: it doesn’t leave any residue behind, it’s strong enough to survive on a car, so it’s probably good enough for a laptop on a desk, and it’s easy to apply.

With some stickers applied to this larger sticker, everything looked good and lived up to a few months of abuse. Then came the real test: could this MacBook wrap be removed with all the other stickers intact? Yes, and you can frame the result. While this is only a test of the aluminum-colored MacBook, vehicle wraps come in nearly every color imaginable. There is apparently a vinyl that looks like Space Gray, and if you want Thinkpad Black, you can get that wrap, too.

Lessons Learned From An Art Installation Build

July 11, 2019 by Lewin Day 7 Comments

Art installations are an interesting business, which more and more often tend to include electronic or mechanical aspects to their creation. Compared to more mainstream engineering, things in this space are often done quite a bit differently. [Jan Enning-Kleinejan] worked on an installation called Prendre la parole, and shared the lessons learned from the experience.

The installation consisted of a series of individual statues, each with an LED light fitted. Additionally, each statue was fitted with a module that was to play a sound when it detected visitors in proximity. Initial designs used mains power, however for this particular install battery power would be required.

Arduinos, USB power banks and ultrasonic rangefinders were all thrown into the mix to get the job done. DFplayer modules were used to run sound, and Grove System parts were used to enable everything to be hooked up quickly and easily. While this would be a strange choice for a production design, it is common for art projects to lean heavily on rapid prototyping tools. They enable inexperienced users to quickly and effectively whip up a project that works well and at low cost.

[Jan] does a great job of explaining some of the pitfalls faced in the project, as well as reporting that the installation functioned near-flawlessly for 6 months, running 8 hours a day. We love to see a good art piece around these parts, and we’ve likely got something to your tastes – whether you’re into harmonicas, fungus, or Markov chains.

The Physics Behind Antennas

July 11, 2019 by Al Williams 34 Comments

If you have done any sort of radio work you probably have a fair idea about what antennas do. It is pretty easy to have a cursory understanding of them, too. You probably know there’s something magic about antennas that are a quarter wave long or a half wave long and other multiples. But do you know why that matters? Do you understand the physics of why wire in a special configuration will cause signals to propagate through space? [Learn Engineering] does, and their new video is one of the best graphical explanations of what’s really going on in an antenna that we’ve seen. You can watch the video below.

If you tackle antennas using math, it is a long discussion. However, this video is about 8 minutes long and uses some great graphics to show how moving charges can produce a propagating electromagnetic field.

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Motorized Lens Controller Techs Up Your Webcam

July 11, 2019 by Lewin Day 13 Comments

If you’re familiar with the DSLR camera market, you’d know that modern lenses are works of technological art. Crammed full of motors and delicate electronic assemblies, they’re bursting with features such as autofocus, optical stabilization and zoom. [Saulius Lukse] has been experimenting with motorized lenses for webcam applications, and has built a controller to make working with them a snap.

The controller is capable of controlling up to 3 stepper motors, as well as a voice coil, which should be enough for the vast majority of lenses out there. Microstepping is supported, which is key for optical systems in which tiny adjustments can make a big difference. The controller speaks USB and I2C, and is now based on an STM32 chip, having been upgraded from an earlier version which used the venerable ATmega328. The board is designed to be as compact as possible, to enable it to neatly fit inside camera and lens assemblies.

The board has been used to successfully control an 18x zoom lens, among others. Combining such a lens with a webcam and a good pan and tilt mechanism would create a highly capable surveillance package, or an excellent vision system for a robot.

It’s not the first time we’ve seen work from [Kurokesu] in these parts – they’ve done work on pedestrian detection before, too.

This Nerf Gun Is Terrifyingly Huge

July 11, 2019 by Lewin Day 10 Comments

Gatling guns were an early attempt at creating a rapid-firing weapon, and were popular amongst armies in the 19th century. Today, the basic design remains in use as a heavy weapon for putting many rounds downrange very quickly. [Ivan Miranda] decided that the Nerf world was missing a piece of the action, and got started on his own design (Youtube link, embedded below).

As per most [Ivan] builds, this one is a glorious pile of 3D printed parts turned into something functional and fun. It’s an ingenious design that’s more a Gatling in spirit than reality as it lacks the multiple barrels of the original, and it uses smart ducting to allow a single electric fan to both fire the foam Nerf balls as well as suck them in to reload the next shot. In testing, it achieved a muzzle velocity of 60 mph, firing at a rate of approximately 10 rounds/second. The presentation is great too, with plenty of cable wrap, meaty switches, and glowing lights to add to the aesthetic. There are even a couple of bright LED lamps on the front to help dazzle your targets into submission.

Once again, [Ivan]’s work is a great example of what is achievable with a 3D printer and smart design. His water jet drive ain’t bad, either. Video after the break.

Continue reading “This Nerf Gun Is Terrifyingly Huge” →

Adding LoRa Long Range Radio To Smartphones And Connected Devices

July 11, 2019 by Brian Benchoff 41 Comments

Would you add another radio to your smartphone? No, not another WiFi or cellular radio; a smartphone already has that. I’m talking about something that provides connectivity through ISM bands, either 433 or 915 MHz. This can be used where you don’t have cell phone coverage, and it has a longer range than WiFi. This is the idea behind Skrypt, a messaging system that allows you to send off-the-grid messages.

Skrypt is an ESP32-based hardware modem that can communicate with a smartphone, or any other device for that matter, over Bluetooth or USB. Inside, there are two modules, an ESP32 WROOM module that provides the Bluetooth, WiFi, USB connectivity, and all of the important software configuration and web-based GUI. The LoRa module is the ubiquitous RFM95W that’s ready to drop into any circuit. Other than that, the entire circuit is just a battery and some power management ICs.

While LoRa is certinaly not the protocol you would use for forwarding pics up to Instagram, it is a remarkable protocol for short messages carried over a long range. That’s exactly what you want when you’re out of range of cell phone towers — those pics can wait, but you might really want to send a few words to your friends. That’s invaluable, and LoRa makes a lot of sense in that case.