3D Printing, Cybersecurity, and Audio Fingerprinting

We all understand the risk of someone taking over our computers or phones for nefarious purposes. But remote access to printers and fax machines was something most people took a little less seriously. After all, you might get some obscene printouts or someone wasting some paper, but in general, those are not big deals. Some researchers however have lately been pondering what might happen should someone break into your 3D printer. Of course, you could bring a printer down to deny service, or cause things to malfunction — maybe even in ways that could be dangerous if the printer didn’t have sufficient safety features. But these researchers are more crafty. They are studying how you know what you’ve printed hasn’t been subtly sabotaged. They also think they have an answer.

If you are printing another Benchy at home this probably isn’t a real concern. However, according to the paper, 3D printing now accounts for over $6 billion of revenue with 33.8% of all parts having some function. This includes a recent FAA approval for a 3D-printed fuel nozzle for a jet engine. So indulge us in a little science fiction. You are about to fly your drone to take video of an important social function. You are worried about one of your props, so you 3D print a new one. Too bad your competitor has hacked your computer with a phishing e-mail and modified your STL files so that the new prop will have built-in weak spots internally. The prop will look fine and you’ll be able to install it. But it is going to fail right when you are taking those critical shots.

Continue reading “3D Printing, Cybersecurity, and Audio Fingerprinting”

Help With Stuttering Could Come From Electricity

At the University of Oxford, [Jen Chesters] conducts therapy sessions with thirty men in a randomized clinical trial to test the effects of tDCS on subjects who stutter. Men are approximately four times as likely to stutter and the sex variability of the phenomenon is not being tested. In the randomized sessions, the men and [Jen] are unaware if any current is being applied, or a decoy buzzer is used.

Transcranial Direct Current, tDCS, applies a small current to the brain with the intent of exciting or biasing the region below the electrode. A credit-card sized card is used to apply the current. Typically, tDCS ranges from nine to eighteen volts at two milliamps or less. The power passing through a person’s brain is roughly on par with the kind of laser pointer you should not point straight into your eyeball and is considered “safe,” with quotation marks.

A week after the therapy, conversational fluency and the ability to recite written passages shows improvement over the placebo group which does not show improvement. Six weeks after the therapy, there is still measurable improvement in the ability to read written passages, but sadly, conversational gains are lost.

Many people are on the fence about tDCS and we urge our citizen scientists to exercise all the caution you would expect when sending current through the brain. Or, just don’t do that.

Open Source Power Converter For The Masses

GaN or Gallium Nitride Transistors have been in the news for their high-frequency and high-efficiency applications. Anyone interested in the Power Converter domain will love this open-source project by Siemens. The offering is called SDI TAPAS and it is a multipurpose GaN FET based board with a TMS320F28x controller onboard.

A quick look at the schematic reveals a lot of stuff going on like current and voltage sense chips along with a neatly designed GaN power stage with by-the-book drivers. There is a plethora of connectors on-board including one for the Raspberry Pi which is an added bonus. The git repository comes with sample code to get you off the ground, with examples running BLDC motors as well as connect it to Siemens MindSphere Cloud Platform.

This platform can be used in a number of functions in addition to motor control, such as battery charging, solar energy harvesting, and wireless charging. There is a presentation(PDF) that is available for download, and if you are looking for use cases there are a number of user build projects on their community site. The schematic and board designs can be used to make your own, or you could ask them for a sample board and they might give away more on their community site.

For those starting out, you might appreciate this tutorial on Buck Converter Efficiency to get a feel for the hardware that goes into such experiments.

Simple RC to USB Interface

With the radio control hobby arguably larger now than it ever has been in the past, there’s a growing demand for high-fidelity PC simulators. Whether you want to be able to “fly” when it’s raining out or you just want to practice your moves before taking that expensive quadcopter up for real, a good simulator on your computer is the next best thing. But the simulator won’t do you much good if it doesn’t feel the same; you really need to hook your normal RC transmitter up to the computer for the best experience.

[Patricio] writes in to share with us his simple hack for interfacing his RC hardware to his computer over USB. Rather than plugging the transmitter into the computer, his approach allows the receiver to mimic a USB joystick. Not only is this more convenient since you can use the simulator without wires, but it will make sure that the minutiae of your radio hardware (such as response lag) is represented in the simulation.

The setup is actually very simple. [Patricio] used the ATtiny85 based Digispark development board because it’s what he had on hand, but the principle would be the same on other microcontrollers. Simply connect the various channels from the RC receiver to the digital input pins. RC receivers are 5 VDC and draw very little current, so it’s even possible to power the whole arrangement from the USB port.

On the software side, the Arduino sketch does about what you expect. It loops through listening for PWM signals on the input pins, and maps that to USB joystick position information. The current code only supports three channels for a simple airplane setup (X and Y for joystick, plus throttle), but it should be easy enough to follow along and add more channels if you needed them for more complex aircraft.

For more information on the intricacies of RC transmitter and receiver interaction, check out this fascinating research on receiver latency.

Twenty Power Harvesting Projects Headed to the Hackaday Prize Finals

The Academy Awards of hardware creation is going on right now! The Hackaday Prize is a challenge to you — yes, you — to create the next great piece of Open Hardware. It is simply incomparable to anything else, and we have the projects to show for it.

Last week, we wrapped up the Power Harvesting Challenge portion of The Hackaday Prize. Now we’re happy to announce twenty of those projects have been selected to move onto the final round and have been awarded a $1000 cash prize. Congratulations to the winners of the Power Harvesting Challenge portion of the Hackaday Prize. Here are the winners, in no particular order:

Continue reading “Twenty Power Harvesting Projects Headed to the Hackaday Prize Finals”

Edwin Armstrong’s Battle for FM Radio

Chances are you have at least one radio that can receive FM stations. Even though FM is becoming less used now with Internet and satellite options, it still is more popular than the older AM radio bands. FM was the brainchild of an inventor you may have heard of — Edwin Armstrong — but you probably don’t know the whole story. It could make a sort of radio-themed soap opera. It is a story of innovation, but also a story of personal vanity, corporate greed, stubbornness, marital problems, and even suicide. The only thing missing is a long-lost identical twin sibling to turn it into a full telenovela.

Early Days

Armstrong grew up in New York and because of an illness that gave him a tic and caused him to be homeschooled, he was somewhat of a loner. He threw himself into his interest in electric and mechanical devices. By 1909 he was enrolled in Columbia University where professors noted he was very focused on what interested him but indifferent to other studies. He was also known as someone more interested in practical results than theory. He received an electrical engineering degree in 1913.

Unlike a lot of college graduates, Armstrong didn’t go work for a big firm. Instead, he set up a self-financed independent lab at Columbia. This sounded good because it meant that he would own the patents on anything invented there. But it would turn out to be a two-edged sword.

Continue reading “Edwin Armstrong’s Battle for FM Radio”

Custom LCD Module is Unexpectedly Cheap and Easy

Looking to take your project to the next level in terms of functionality and appearance? A custom LCD display might be the thing that gets you there, at least compared to the dot-matrix or seven-segment displays that anyone and their uncle can buy from the usual sources for pennies. But how does one create such a thing, and what are the costs involved? As is so often the case these days, it’s simpler and cheaper than you think, and [Dave Jones] has a great primer on designing and specifying custom LCDs.

The video below is part of an ongoing series; a previous video covered the design process, turning the design into a spec, and choosing a manufacturer; another discussed the manufacturer’s design document approval and developing a test plan for the module. This one shows the testing plan in action on the insanely cheap modules – [Dave] was able to have a small run of five modules made up for only $138, which included $33 shipping. The display is for a custom power supply and has over 200 segments, including four numeric sections, a clock display, a bar graph, and custom icons for volts, amps, millijoules, and watt-hours. It’s a big piece of glass and the quality is remarkable for the price. It’s not perfect – [Dave] noted a group of segments on the same common lines that were a bit dimmer than the rest, but was able to work around it by tweaking the supply voltage a bit.

We’re amazed at how low the barrier to entry into custom electronics has become, and even if you don’t need a custom LCD, at these prices it’s tempting to order one just because you can. Of course, you can also build your own LCD display completely from scratch too.

Continue reading “Custom LCD Module is Unexpectedly Cheap and Easy”