This week Hackaday Editor-in-Chief Elliot Williams and Managing Editor Tom Nardi take a close look at two pairs of projects that demonstrate the wildly different approaches that hackers can take while still arriving at the same conclusion. We’ll also examine the brilliant mechanism that the James Webb Space Telescope uses to adjust its mirrors, and marvel over a particularly well-developed bot that can do your handwriting for you. The finer points of living off home-grown algae will be discussed, and by the end of the show, you’ll learn the one weird trick to stopping chip fabs in their tracks.
Take a look at the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!
A hacker is somebody who’s always thinking creatively to solve problems, usually using what they have on hand. Sometimes that means using a 555 to build a CPU, and other times it means using a dead flashlight to start a fire. In the video below the break, [Kelly] shows us a series of hacks you can use while camping in the woods for a night to keep you warm, dry, and well fed!
[Kelly] started his camping trip not in the woods, but rather at a local thrift store. Instead of packing along hundreds of dollars in gear, his aim was to keep costs low. Very low. With some searching he was able to find a blanket, cooking utensils, rope, knife, tarp, and several other camp necessities for just $25.
A good campfire is a necessity of course, and [Kelly]’s full of great ways to start a fire even if all you have is a lighter with no butane or an old flashlight with dead batteries. The purpose of the video is to show how anyone can get their bush craft on even when all they have is a few dollars and a little know-how, which he generously shares. And after watching, we’re sure you’ll agree that he met his mark.
Will you raid the local second hand store before your next camping trip? After seeing this video, you just might! And while you’re there, make sure to grab the things you’ll need to make your own camping-friendly French press so you have some good coffee while you’re out camping in your… uh… Corolla?
We’ve now spent several months in this series journeying through the world of audio, and along the way we’ve looked at the various parts of a Hi-Fi system from the speaker backwards to the source. It’s been an enjoyable ride full of technical detail and examining Hi-Fi myths in equal measure, but now it’s time to descend into one of the simplest yet most controversial areas of audio reproduction. Every audio component, whether digital or analogue, must be connected into whatever system it is part of, and this is the job of audio cables, sometimes referred to as interconnects. They are probably the single component most susceptible to tenuous claims about their performance, with audiophiles prepared to spend vast sums on cables claimed to deliver that extra bit of listening performance. Is there something in it, or are they all the same bits of wire with the expensive ones being a scam? Time to take a look.
What Makes A Nearly Good Cable
In a typical domestic audio system with digital and analogue signals you might expect to find two types of cable, electrical interconnects that could carry either analogue or digital signals, and optical ones for digital signals. We’re here to talk about the electrical cables here as they’re the ones used for analogue signals, so lets start with a little transmission line theory. Continue reading “Know Audio: A Mess Of Cables”→
We all know that you can convert heat into electricity. Usually, you do that with some form of steam, but there are other methods, too, including thermocouples. If you’ve ever seen something producing waste heat, you’ll appreciate Penn State’s work to harvest power from hot pipes. The idea is simple in theory: create a flexible thermoelectric generator that can wrap around hot pipes or other surfaces to gather otherwise lost heat. The full (paywalled) paper is also available.
The devices can produce up to 150% more power per unit area compared to other thermoelectric generators. A three-square-inch test device produced over 50 watts. Scale that up to an industrial pipe hundreds of feet long, and you could create some serious power. To accomplish this, the scientists used strips of six thermocouples and connected them for a total of 72 thermocouples. Liquid metal between layers improved the device’s performance.
This isn’t a totally new idea. Russia was famous for making radios in the 1950s that operated using a generator that went around the flue of a kerosene lamp. Since the Russians were pulling this off in the 1950s, converting heat into electricity is obviously nothing new. Of course, your body creates heat, too, so why not use that?
[Robert Murray-Smith] wanted to recreate how some ancient microscopes worked: with a drop of water as a lens. The idea is that the meniscus of a drop of water will work as a lens. This works because of surface tension and by controlling the attraction of the water to the surface, you can actually form convex and concave surfaces.
What’s interesting is that this doesn’t require a lot of equipment. Some plastic, a hole punch, some pens, a flashlight, and some other odds and ends. Then it’s just a matter of grabbing some puddle water and examining the critters inside. Of course, with a single lens, these are more properly magnifying glasses. Some claim that people in China built such instruments thousands of years ago. [Robert] mentions [Antonie van Leeuwenhoek] as the father of the microscope, although he wasn’t the first to build such a device. He did create amazing glass lenses using a method he kept secret but has been worked out using modern science.
It is hard to see much through the camera, but it clearly was magnifying. Not a bad little rainy day kid’s project since you probably have everything you need on hand. We wonder what other readily-available things you could image with a device like this.
Of course, if you want to build a real microscope, the designs are out there. You can even make one using — mostly — LEGO.
At this point, everyone knows that the print quality you’ll get from even an entry level UV resin printer far exceeds what’s possible for filament-based fused deposition modeling (FDM) machines. But there’s a trade-off: for the money, you get way more build volume by going with FDM. So until the logistics of large-format resin printers gets worked out, folks looking to make things like replica prop helmets have no choice but to put considerable time into post-processing their prints to remove the obvious layer lines.
But thanks to this somewhat ironic trick demonstrated by [PropsNstuff], you can actually use UV resin to improve the finish quality of your FDM prints. The idea is to put a layer of resin over the layer lines and other imperfections of the 3D print, cure it with a handheld UV flashlight, and then sand it smooth. Essentially it’s like using resin in place of a body filler like Bondo, with the advantage here being that the resin cures in seconds.
With the tough spots addressed, he then moves on to coating larger areas with resin. But this time, he mixes leftover resin from his SLA printer with talcum powder to make a mix that can be brushed on without running everywhere. It takes a few thin coats, but with this mix, he’s able to build up large swaths of the print without losing any surface detail.
Is it still a hassle? Absolutely. But the final result does look spectacular, so until we figure out how to build the replicators from Star Trek, it looks like we’ll have to make up for our technological shortcomings with the application of a little elbow grease.
String shooters are exciting because they adhere to the laws of physics in that peculiar way that makes us ask, “How?” and “Why?” After a bit of poking and prodding, maybe some light rope burn, we probably have a few ideas on how we’d make our own. [Nick Belsten] and [Joey Rain] saw some desktop models and thought, “Let’s make that puppy eighty feet long!” Video also embedded after the break.
Instead of hobby motors, flashlight batteries, and toy car wheels, they choose a washing machine motor and bike tires, then plug into an extension cord. The three-minute video isn’t a how-to build because once you start welding this kind of hardware together, you are already flying by the seat of your pants. You will see a front yard with people delighting in the absurdity of launching rope continuously over the treetops. There’s plenty of room for observing a wave traveling along the cord or polishing your fingernails in a hurry.
We want to make string shooters for the office and add our personal flavor, like lights or colored string so they’re safe to touch. If you have a unique twist on any physics experiments, drop us a line, but for insurance reasons, we’ll add that you should not make a chainsaw without a guide bar, aka, the forbidden chain-saber.
