OpenEMS Makes Electromagnetic Field Solving… Merely Difficult

To ordinary people electronics is electronics. However, we know that the guy you want wiring your industrial furnace isn’t the guy you want designing a CPU. Neither of those guys are likely to be the ones you want building an instrumentation amplifier. However, one of the darkest arts of the electronic sects is dealing with electromagnetic fields. Not only is it a rare specialty, but it requires a lot of high-powered math. Enter OpenEMS, a free and open electromagnetic field solver.

We would like to tell you that OpenEMS makes doing things like antenna analysis easy. But that’s like saying Microsoft Word makes it easy to write a novel. In one sense, yes, but you still need to know what you are doing. In fairness, though, the project does provide a good set of tutorials, ranging from a simple wave guide to a sophisticated phased array of patch antennas. Our advice? Start with the waveguide and work your way up from there.

The software uses Octave or MATLAB for scripting, plotting, and support. You can download it for Windows or Linux.

If you want to start with something more intuitive for electromagnetic field visualization, this might help. If you prefer your models more concrete and less abstract, perhaps you should work at Lincoln Lab.

Flying Defibrillators

It’s a sad reality that, by and large, cardiopulmonary resuscitation (CPR) doesn’t save lives. Despite all the “you could save a life” marketing aimed at getting people certified in CPR, the instances where even the prompt application of the correct technique results in a save are vanishingly rare, and limited mostly to witnessed arrests in a hospital. Speaking from personal experience, few things are sadder than arriving on-scene as a first responder to see CPR being performed by a husband on his wife and knowing that no matter what we do, it’s not going to end well.

The problem is one of time. Hearts only rarely just stop beating outright; usually some kind of arrhythmia first causes the heart to beat ineffectively, leading to hypoxia and loss of consciousness. From there it’s about a four-minute trip to brain death, but in that brief window chances are pretty good that the heart can be restarted. That’s why witnessed cardiac arrests in a hospital have better survival rates — the needed electric reboot of the heart with a defibrillator is only as far away as the nearest crash cart.

The advent of the automatic external defibrillator (AED) has increased the odds for survival of out-of-hospital cardiac arrest (OHCA), but the penetration of AEDs into public settings is far from complete enough to put one within a few minutes reach of everyone who might need one. So it’s only natural that thoughts would turn to delivering AEDs to cardiac incidents by drones. It seems like a great idea, but will it work? Continue reading “Flying Defibrillators”

Bristle bot controversy


When the Bristlebots were released back in 2007 by Evil Mad Scientist Laboratories, we all thought they were pretty cool. Apparently someone at Klutz did too. They have released a book, with the title “Invasion of the BristleBots”. The bots seem to be identical and the name is identical. There is no mention of Evil Mad Scientist Laboratories anywhere in it. [Phillip Torrone] has attempted to contact Klutz and the book publisher Scholastic directly to find out more information.

[Windell] and [Lenore] from EMSL had this to say:

“This is the first that I’ve heard of it. Frankly, I am a bit offended. Klutz makes some nice things, and I’m surprised that they wouldn’t have contacted us, asked permission, or at least given us credit. (Locomotion by ratcheting bristles isn’t remotely new — it occurs in nature — but the name ‘Bristlebot’ is surely ours, and I don’t know of any prior implementation with a toothbrush.)”

You probably know EMSL from their other projects such as the Peggy and Meggy jr. How would you feel if a project you did was published without credit? Would you care or not?

EMS Synthi AKS teardown

Here’s another bit of analog synth pr0n for you: Initially sold in 1972, the EMS Synthi AKS was a portable modular analog synthesizer with a built in keyboard and sequencer. The VCS 3 portion of the device had a unique routing matrix pegboard used to connect components together. [firegroove] has opened up his precious machine so that you can see all of the fine little bits that make it tick… and chirp.

[via Matrixsynth]