Relay Computing

Recently, [Manuel] did a post on making logic gates out of anything. He mentioned a site about relay logic. While it is true that you can build logic gates using switch logic (that is, two switches in series are an AND gate and two in parallel are an OR gate), it isn’t the only way. If you are wiring a large circuit, there’s some benefit to having regular modules. A lot of computers based on discrete switching elements worked this way: you had a PCB that contained some number of a basic gate (say, a two input NAND gate) and then the logic was all in how you wired them together. And in this context, the SPDT relay was used as a two input multiplexer (or mux).

In case you think the relay should be relegated to the historical curiosity bin, you should know there are still applications where they are the best tool for the job. If you’re not convinced by normal macroscopic relays, there is some work going on to make microscopic relays in ICs. And even if they don’t use relays to do it, some FPGAs use mux-based logic inside.  So it’s worth your time to dig into the past and see how simply switching between two connections can make a computer.

Mux Mania

How do you go from a two input mux to an arbitrary logic gate? Simple, if you paid attention to the banner image. (Or try it interactive). The mux symbols show the inputs to the left, the output to the right and the select input at the bottom. If the select is zero, the “0” input becomes the output. If the select is one, the “1” input routes to the output.

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Friday Hack Chat: KiCad EDA Suite with Wayne Stambaugh

KiCad is the premiere open source electronics design automation suite. It’s used by professionals and amateurs alike to design circuits and layout out printed circuit boards. In recent years we’ve seen some incredible features added to KiCad like an improved 3D viewer and push-and-shove routing. This Friday at 10 am PST, join in a Hack Chat with KiCad lead developer [Wayne Stambaugh] to talk about recent improvements and what the team has planned for KiCad in the future.

[Wayne] has been an electronics engineer for over 30 years with a wide range of experience in analog and digital hardware design and embedded and application software design. He started hacking on KiCad ten years ago when the project was first opened to public development and a little over two years ago became the project leader. This is an excellent opportunity to learn how the development team works, what their current goals are, and to talk all things KiCad.

Don’t miss this Hack Chat! Here’s a handy web tool to help convert Jan. 20 at 10:00 am PST to your local time.

Wait, There’s Tindie Too!

Also on Friday, taking place just an hour before the KiCad chat, is a Tindie Hack Chat. All are welcome as the 9:00 am PST discussion gets under way. Discussion will focus on all aspects of selling unique hardware on Tindie.

Here’s How to Take Part:

join-project-team-message-buttons
Buttons to join the project and enter Hack Chat

Hack Chat are live community events that take place in the Hackaday.io Hack Chat group messaging. Visit that page (make sure you are logged in) and look for the “Join this Project Button” in the upper right. Once you are part of the project, that button will change to “Team Messaging” which takes you to the Hack Chat.

You don’t have to wait for Friday, join Hack Chat whenever you like and see what the community is currently talking about.

 Join Us Next Week Too for CircuitPython

Block out your calendar for noon PST on Friday the 27th for next week’s Hack Chat. Joining us are Adafruit’s Ladyada, Tony DiCola, and Scott Shawcoft. They’ll be leading a discussion about CircuitPython Beta, Adafruits new extension to MicroPython that adds SAMD21 support and other enhancements.

Understanding The Quartz Crystal Resonator

Accurate timing is one of the most basic requirements for so much of the technology we take for granted, yet how many of us pause to consider the component that enables us to have it? The quartz crystal is our go-to standard when we need an affordable, known, and stable clock frequency for our microprocessors and other digital circuits. Perhaps it’s time we took a closer look at it.

The first electronic oscillators at radio frequencies relied on the electrical properties of tuned circuits featuring inductors and capacitors to keep them on-frequency. Tuned circuits are cheap and easy to produce, however their frequency stability is extremely affected by external factors such as temperature and vibration. Thus an RF oscillator using a tuned circuit can drift by many kHz over the period of its operation, and its timing can not be relied upon. Long before accurate timing was needed for computers, the radio transmitters of the 1920s and 1930s needed to stay on frequency, and considerable effort had to be maintained to keep a tuned-circuit transmitter on-target. The quartz crystal was waiting to swoop in and save us this effort.

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Review: Hammer-Installed Solderless Raspberry Pi Pin Headers

A few days ago we reported on a new product for owners of the Raspberry Pi Zero, a set of solderless header pins that had a novel installation method involving a hammer. We were skeptical that they would provide a good contact, and preferred to stick with the tried-and-trusted soldered pins. It seems a lot of you agreed, and the comments section of the post became a little boisterous. Pimoroni, the originator of the product, came in for a lot of flak, with which to give them their due they engaged with good humor.

It’s obvious this was a controversial product, and maybe the Hackaday verdict had been a little summary based on the hammer aspect of the story. So to get further into what all the fuss had been about I ordered a Pi Zero and the solderless pin kit to try for ourselves.

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Hackaday Links: January 15, 2017

What’s more expensive than a car and a less useful means of transportation? A 747 flight simulator built in a basement. There’s a project page where a few more details are revealed. There’s a 180 degree wrap-around screen for the main display, a glass cockpit, and the controls and gauges are ‘good enough’ to feel like the real thing. The simulator is running a highly customized version of FS9 (Microsoft’s flight sim from the year 2004).

For the last few years, Google has been experimenting with high altitude balloons delivering Internet to remote populations. This is Project Loon, and simply by the fact that Google hasn’t shuttered this Alpha-bit, we can assume the project is a success. A Project Loon balloon recently crashed in Panama, which means we can get an up-close look at the hardware. These balloon base stations are a lot bigger than you would think.

We’ve seen beautiful PCBs before, but [Blake] is taking this to another level entirely. He’s developed a process to convert bitmaps into files suitable to send to a PCB manufacturer. The results are… strange, and very cool. Check out a video of the process here.

If you want to dial out from behind the great firewall of China, you’re probably going to use a VPN. Here’s an idea that doesn’t work as well as a VPN. Use an acoustic coupler with your iPhone. Will it work? Of course it will – modems have been standardized for fifty years. Will it work well? No, I can speak faster than 300 baud.

Do you sell on Tindie? We have a dog park. Tindie sellers around the world will be meeting up on Hackaday.io next Friday to discuss Tindie and Tindie-related activities. Join in!

A quick aside relating to Hackaday and Tindie swag. 1) The Tindie dog as a stuffed animal. 2) A Hackaday logo t-shirt where the skull is decorated like a Día de Muertos sugar skull. Pick one, leave your response in the comments.

Retrotechtacular: Social Hacking is Nothing New

If you watch enough mainstream TV and movies, you might think that hacking into someone’s account requires a huge monitor, special software, and intricate hand gestures. The reality is way more boring. Because people tend to choose bad passwords, if you have time, you can task a computer with quietly brute-forcing the password. Then again, not everyone has a bad password and many systems will enforce a timeout after failed attempts or require two-factor authentication, so the brute force approach isn’t what it used to be.

Turns out the easiest way to get someone’s password is to ask them for it. Sure, a lot of people will say no, but you’d be surprised how many people will tell you. That number goes up dramatically when you make them think you are with the IT department or their Internet provider. That’s an example of social engineering. You can define that many ways, but in this case it boils down to getting people to give you what you want based on making them believe you are something you aren’t.

Everything Old…

We think of social engineering as something new, but really–like most cybercrime–it is just the movement of old-fashioned crime to the digital world. What got me thinking about this is a service from Amazon called “Mechanical Turk.”

That struck me as odd when I first heard it because for product marketing it is pretty bad unless you are selling turkey jerky or something. If you tell me “Amazon Simple Storage Service” I can probably guess what that might be. But what’s Mechanical Turk?

Mechanical Turk

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Sophi Kravitz: State of the IO

At the Hackaday SuperConference in November, Sophi Kravitz had the chance to look back on the past year of Hackaday.io, and what a great year it has been. Hackaday.io now has over 178k members who have published 12.6k projects with about 10% of those being collaborative team projects. But the numbers tell just a small story of the vibrant community Hackaday has.

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