Physics Or Phiction?

October 26, 2016 by Al Williams 15 Comments

Do you remember Gilligan’s Island? For many people of a certain age, “The Professor” was our first impression of what a scientist was like. Even in those simpler times, though, you probably couldn’t find anyone like the professor; a jack of all trades, he sort of knew everything about everything (except, apparently, how to make a boat).

Real scientists tend to hyper-specialize. Getting grant money, publication pages, and just advancing the state of the art means that you get more and more focused on more obscure things. It is getting to the point that two scientists in the same field may not be able to really understand each other. You see the same thing in engineering to some degree. Not many digital designers can talk about the frequency dependence of Early effect in bipolar transistors, but not many device gurus can talk intelligently about reservation techniques for superscalar CPUs.

There’s now a website that lets you guess if a physics paper title is real or if it made up jibberish. The site, snarXiv, gets the real titles from arXiv, the site that contains many preprint papers. For example, we were asked to guess if “Brane Worlds with Bolts” was a real paper or if it was “Anthropic Approaches to the Flavor Problem.” (For the record, it was the one about branes.) Give it a whirl!

Retrofitting Smoke Alarms With Bluetooth

October 26, 2016 by Brian Benchoff 46 Comments

Everybody should have a few smoke alarms in their house, and everyone should go check the battery in their smoke alarm right now. That said, there are a few downsides to the traditional smoke alarm. They only work where you can hear them, and this problem has been solved over and over again by security companies and Internet of Things things.

Instead of investing in smart smoke alarms, [Johan] decided to build his own IoT smoke alarm. It’s dead simple, costs less than whatever wonder gizmo you can buy at a home improvement store, and reuses your old smoke alarm. In short, it’s everything you need to build an Internet-connected smoke alarm.

Smoke alarms, or at least ionization-based alarms with a tiny amount of radioactive americium, are very simple devices. Inside the alarm, there’s a metal can – an ionization chamber – with two metal plates. When smoke enters this chamber, a few transistors sound the alarm. If you’ve ever taken one apart, you can probably rebuild the circuit from memory.

Because these alarms are so simple, it’s possible to hack in some extra electronics into a design that hasn’t changed in fifty years. For [Johan]’s project, he’s doing just that, tapping into one of the leads on the ionization chamber, measuring the current through the buzzer, and adding a microcontroller with Bluetooth connectivity.

For the microcontroller and wireless solution, [Johan] has settled on TI’s CC2650 LaunchPad. It’s low power, relatively cheap, allows for over the air updates, and has a 12-bit ADC. Once this tiny module is complete, it can be deadbugged into a smoke alarm with relative ease. Any old phone can be used as a bridge between the alarm network and the Internet.

The idea of connecting a smoke alarm to the Internet is nothing new. Security companies have been doing this for years, and there are dozens of these devices available at Lowes or Home Depot. The idea of retrofitting smarts into a smoke alarm is new to us, and makes a lot of sense: smoke detectors are reliable, cheap, and simple. Why not reuse what’s easy and build out from there?

An Open Source 96 MSPS Logic Analyzer For $22

October 26, 2016 by Jenny List 66 Comments

If you are in the market for an inexpensive USB logic analyser you have a several choices, but few of them deliver much in the way of performance. There are kits from China for a few dollars using microcontrollers at their heart, but they fail to deliver significant sample rates. If you require more, you will have to pay for it.

It is therefore rather interesting to see [kevinhub88]’s SUMP2 project, an open source logic analyser with a claimed 96 MSPS sample rate using an off-the-shelf Lattice iCEstick FPGA evaluation board that only costs about $20. ~~It talks to a host computer via USB using the established SUMP protocol, so its software front-end comes from the sump.org logic analyser project~~. Edit: Since this post was published [Kevin] has contacted us to inform us that the project’s capabilities have now moved beyond SUMP’s capabilities and in fact it now uses his own software.

This project has the promise to add a very useful piece of test equipment to the armoury of the engineer on a budget, and to aid the cost-conscious reader he’s provided extensive documentation and installation instructions, as well as the code for the FPGA. Thanks to one of the more awesome hacks of 2015, there is an entirely open toolchain for this Lattice part, and our own [Al Williams] has written up a multi-part getting-started guide if you want to get your feet wet. You probably want one of these anyway, and now it’s a logic analyzer to boot.

We’ve covered quite a few inexpensive home-produced digital instruments here over the years, including this logic analyser with a slightly higher price tag, this inexpensive VNA, and this oscilloscope board. Maybe one day the bench of our dreams will all come on one open-source PCB for $100, who knows!

Converting A TP Link Router To Mission Control For Cheap 433MHz Home Automation

October 26, 2016 by Gerrit Coetzee 11 Comments

[Jean-Christophe Rona] found himself with some free time and decided to finish a project he started two years ago, reverse engineering cheap 433MHz home automation equipment. He hopes to control his space heaters remotely, in preparation for a cold and, now, robotic winter.

In a previous life, he had reverse engineered the protocol these cheap wireless plugs, garage doors, and electric window shutters all use. This eventually resulted in a little library called rf-ctrl that can toggle and read GPIO pins in the correct way to control these objects. He has a few of the more popular protocols built into the library and even wrote a guide on how to do the reverse engineering yourself if you have need.

Having successfully interfaced with the plugs to use with his space heaters, [Jean-Christophe] went about converting a cheap TP Link router into a command center for them. Since TP Link never expected anyone to hammer their square peg into a mismatched hole, it takes a careful hand at soldering and some enamel wire to break out the GPIO pins, but it’s well within the average skill set.

The end result is a nicely contained blue box with a little antenna hanging out of it, and we hope, a warm abode for the coming winter.

Why You Should Own A Sewing Machine

October 26, 2016 by Jenny List 116 Comments

This could probably be any of our grandmothers at work. George Grantham Bain Collection [PD], via Wikimedia Commons.

In our hackspace, we’ve opened a textile room in the last month. We have high hopes for it as a focal point for cosplayers and LARPers as well as the makers of wearable electronics and more traditional textile users. Putting it in has involved several months of hard work bringing a semi-derelict and previously flooded room that was once the walk-in safe for our local school authority to a point at which it is a light and welcoming space, but a surprising amount of work has also had to go into winning the hearts and minds of our community for the project.

Putting it quite simply, textiles aren’t seen as very cool, in hackspace terms. You know, Women’s stuff. Your mother does it, or even maybe if you are a little younger, your grandmother. It’s just not up there with laser cutting or 3D printing, and as a result those of us for whom it’s a big part of making stuff have had to fight its corner when it comes to resources within the space.

Yet not so long ago when I brought a pair of worn-out jeans into the space on a social night and hauled out our Lervia sewing machine to fix them, I had a constant stream of fellow members passing by amazed at what I was doing. “You can repair jeans?” they asked, incredulously. For some reason this prospect had not occurred to them, I was opening up a new vista in clothing reincarnation, to the extent that before too long in our new facility I may be giving a workshop on the subject as the beloved former trousers of Oxford Hackspace denizens gain a chance of new life.

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A Modest But Well-Assembled Home Hydropower Setup

October 26, 2016 by Jenny List 21 Comments

We have all opened an electricity bill and had thoughts of saving a bit of money by generating our own power. Most of us never get any further than just thinking about it, but for anyone willing to give it a try we are very fortunate in that we live in a time at which technology has delivered many new components that make it a much more straightforward prospect than it used to be. Electronic inverters, efficient alternators, and electronic battery management systems are all easy to find via the internet, and are thus only a matter of waiting for the courier to arrive.

[Frédéric Waltzing] is lucky enough to have access to a 135 foot (38 metre) head of water that those of us in flatter environments could only dream of. He’s used it to generate his own power using a modestly sized but very effective turbine, and he documented it in a Youtube video which you can see below the break.

He brings the water to his turbine house through a 1.5 inch plastic pipe, in which he maintains a 55PSI closed pressure that drops to 37PSI when the system is running. His Pelton wheel develops 835RPM, from which a small permanent magnet alternator provides 6.3A for his battery management system. An Enerwatt 2KW inverter provides useful power from the system.

This hydroelectric installation might not be very large, but its key is not in its size but that it can run continuously. A continuous free 6.3A charge can store up a lot of energy for those times when you need it.

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Life On Contract: How To Find Clients As An Engineering Contractor

October 26, 2016 by Mike Szczys 28 Comments

The following is my personal advice, it probably doesn’t apply to all contractors, but it’s certainly applied to me. When you start contracting, your most pressing question is probably “how do I find clients” so here’s what little I’ve learned so far…

1. Don’t

For some, contracting is seen as a potential escape route from the hum-drum of a dull, often political office environment. But contracting isn’t always the answer. Pay, while often better, is inconsistent. I’ve had clients pay two months late (and think it’s normal), pay the wrong amount (due to misunderstanding currency conversion) and just plain forget to sign off an invoice. Chasing down these invoicing issues will all be your job. Clients will say “we’ll definitely hire you” and then a contract will never happen.

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