Even if you don’t work in a nuclear power plant, you might still want to use a Geiger counter simply out of curiosity. It turns out that there are a lot of things around which emit ionizing radiation naturally, for example granite, the sun, or bananas. If you’ve ever wondered about any of these objects, or just the space you live in, it turns out that putting together a simple Geiger counter is pretty straightforward as [Alex] shows us.
The core of the Geiger counter is the tube that detects the radiation. That’s not something you’ll be able to make on your own (probably) but once you have it the rest of the build comes together quickly. A few circuit boards to provide the tube with the high voltage it needs, a power source, and a 3D printed case make this Geiger counter look like it was ordered from a Fluke catalog.
The project isn’t quite finished ([Alex] is still waiting on a BNC connector to arrive) but seems to work great and isn’t too complicated to put together, as far as Geiger counters go. He did use a lathe for some parts which not everyone will have on hand, but a quick trip to a makerspace or machinist will get you that part too. We’ve seen some other parts bin Geiger counters too, so there’s always a way around things like this.
If you walk into a dog owner’s home that dog is probably going to make a beeline to see if you are a threat. If you walk into a cat owner’s home, you may see the cat wandering around, if it even chooses to grace you with its presence. For some people, a dog’s direct approach can be nerve-wracking, or even scary depending on their history and relative size of the dog. Still, these domestic animals are easy to empathize with especially if you or your family have a pet. They have faces which can convey curiosity or smug indifference but what if you were asked to judge the intent of something with no analogs to our own physical features like a face or limbs? That is what researchers at the IDC Herzliya in Israel and Cornell University in the US asked when they made the Greeting Machine to move a moon-like sphere around a planet-like sphere.
Participants were asked to gauge their feelings about the robot after watching the robot move in different patterns. It turns out that something as simple as a sphere tracing across the surface of another sphere can stir consistent and predictable emotions in people even though the shapes do not resemble a human, domestic pet, or anything but a snowman’s abdomen. This makes us think about how our own robots must be perceived by people who are not mired in circuits all day. Certainly, a robot jellyfish lazing about in the Atlantic must feel less threatening than a laser pointer with a taste for human eyeballs.
If you want to learn Morse code and you don’t have a teacher, you’d probably just head over to a website or download a phone app. Before that, you probably bought a cassette tape or a phonograph record. But how did you learn Morse if you didn’t have any of that and didn’t know anyone who could send you practice? Sure, you could listen to the radio, but in 1939 that might be difficult, especially to find people sending slow enough for you to copy.
Wireless World for August 3rd, 1939, has the answer in an article by [A. R. Knipe] on page 109. While you probably wouldn’t use it today, it is a great example of how ingenious you can be when you don’t have an Arduino and all the other accoutrements we take for granted today.
The Unix operating system has been around for decades, and it and its lookalikes (mainly Linux) are a critical part of the computing world. Apple’s operating system, macOS, is Unix-based, as are Solaris and BSD. Even if you’ve never directly used one of these operating systems, at least two-thirds of all websites are served by Unix or Unix-like software. And, if you’ve ever picked up a smart phone, chances are it was running either a Unix variant or the Linux-driven Android. The core reason that Unix has been so ubiquitous isn’t its accessibility, or cost, or user interface design, although these things helped. The root cause of its success is its design philosophy.
Good design is crucial for success. Whether that’s good design of a piece of software, infrastructure like a railroad or power grid, or even something relatively simple like a flag, without good design your project is essentially doomed. Although you might be able to build a workable one-off electronics project that’s a rat’s nest of wires, or a prototype of something that gets the job done but isn’t user-friendly or scalable, for a large-scale project a set of good design principles from the start is key.
If you’re at all like us, or like [Vadim], you’ve got a stash of development boards in a shoebox on a shelf in your closet. If you’re better organized that we are, it might even be labeled “dev boards”. (Ah well, that’s a project for another day.) Anyway, reach into your box and pull one out, and put it to use. Do something trivial if you need to, but a dev board that’s driving a silly blinker is better than a dev board sitting in the dark.
[Vadim]’s good example to us all is going to serve as the brains for an automated plant watering system. That’s a low-demand application where the microcontroller can spend most of the time sleeping. [Vadim]’s first step, then was to get a real-time clock working with the hibernation mode. There’s working code inline in his blog.
If you use Arduino, you’ll feel at home in the Energia ecosystem. But it’s like ordering a Quarter Pounder with Cheese in Paris: Energia is a Royale with Cheese (YouTube) — it’s the little differences. And maybe that’s the point of the exercise; it’s always a good thing to try out something new, even if it’s only minimally different.
So grab that unused dev board off the shelf, struggle through the unfamiliar development environment and/or toolchain, but remember to keep an eye out for the sweet little differences. The more tools that you’re familiar with, the more solutions will spring to mind when you’re hacking on your next project.
It’s no secret that we love bizarre robot locomotion, so we are naturally suckers for BALLU (YouTube link, also embedded below) the Bouyancy-Assisted Lightweight Legged Unit. The project started with a simple observation — walking robots are constrained by having to hold themselves up — and removing that constraint make success much easier. Instead of walking, BALLU almost floats and uses what little net weight it does have to push against the ground.
How many integrated circuits do you need to build up a power supply that’ll convert mains AC into a stable DC voltage? Would you believe, none? We just watched this video by [The Current Source] (embedded below), where he builds exactly that. If you’re in the mood for a very well done review of diode bridges as well as half- and full-wave rectifiers, you should check it out.
First off, [TCS] goes through the basics of rectification, and demonstrates very nicely on the oscilloscope how increasing capacitance on the output smooths out the ripple. (Hint: more is better.) And then it’s off to build. The end result is a very simple unregulated power supply — just a diode bridge with some capacitors on the output — but by using really big capacitors he gets down into the few-millivolt range for ripple into a constant load.
The output voltage of this circuit will depend on the average current drawn, but for basically static loads this circuit should work well enough, and the simplicity of just tossing gigantic capacitors at the problem is alluring. (We would toss in a linear regulator somewhere.)
Quibbling over circuit designs isn’t why you’re watching this video, though. It’s because you want to learn something. Check out the rest of his videos as well. [TCS] has only been at it a little while, but it looks like this is going to be a channel to watch.