Hacking When It Counts: Churchill’s Toy Shop

February 9, 2018 by 47 Comments

Nothing brings out the worst in humanity like war. Perversely, war also seems to exert an opposite if not equal force that leads to massive outbursts of creativity, the likes of which are not generally seen during times of peace. With inhibitions relaxed and national goals to meet, or in some cases where the very survival of a people is at stake, we always seem to find new and clever ways to blow each other to smithereens.

The run-up to World War II was a time where almost every nation was caught on its heels, and the rapidity of events unfolding across Europe and in Asia demanded immediate and decisive response. As young men and women mobilized and made ready for war, teams of engineers, scientists, and inventors were pressed into service to develop the weapons that would support them. For the British, these “boffins” would team up under a directorate called Ministry of Defence 1, or MD1. Informally, they’d be known as “Churchill’s Toy Shop,” and the devices they came up with were deviously clever hacks.

Continue reading “Hacking When It Counts: Churchill’s Toy Shop” →

Neural Network Zaps You To Take Better Photographs

February 9, 2018 by 38 Comments

It’s ridiculously easy to take a bad photograph. Your brain is a far better Photoshop than Photoshop, and the amount of editing it does on the scenes your eyes capture often results in marked and disappointing differences between what you saw and what you shot.

Taking your brain out of the photography loop is the goal of [Peter Buczkowski]’s “prosthetic photographer.” The idea is to use a neural network to constantly analyze a scene until maximal aesthetic value is achieved, at which point the user unconsciously takes the photograph.

But the human-computer interface is the interesting bit — the device uses a transcutaneous electrical nerve stimulator (TENS) wired to electrodes in the handgrip to involuntarily contract the user’s finger muscles and squeeze the trigger. (Editor’s Note: This project is about as sci-fi as it gets — the computer brain is pulling the strings of the meat puppet. Whoah.)

Meanwhile, back in reality, it’s not too strange a project. A Raspberry Pi watches the scene through a Pi Cam and uses a TensorFlow neural net trained against a set of high-quality photos to determine when to trip the shutter. The video below shows it in action, and [Peter]’s blog has some of the photos taken with it.

We’re not sure this is exactly the next “must have” camera accessory, and it probably won’t help with snapshots and selfies, but it’s an interesting take on the human-device interface. And if you’re thinking about the possibilities of a neural net inside your camera to prompt you when to take a picture, you might want to check out our primer on TensorFlow to get started.

Continue reading “Neural Network Zaps You To Take Better Photographs” →

Designing a mini spy bug recorder

Mini Spy Bug Walkthrough

February 9, 2018 by 18 Comments

What we like most about [GreatScott’s] project videos is that he not only shows making them but also the calculations for selecting parts and the modifications along the way. This time he’s made a mini spy bug that records up to nine hours of audio.

His first task was to figure out if the ATmega328p’s ADC is suitable for audio sampling, but only after he explains how sampling works by periodically checking the input voltage from the microphone. Checking the datasheet he found that the ADC’s fastest conversion time is 13 microseconds, which works out to a sampling rate of 76.923 kHz. Good enough.

He then walks through why and how he decided to go with a pre-made amplifier circuit built around the MAX9814 IC. Spoiler alert. His electret’s amplifier output voltage was too low, using an off-the-shelf circuit instead of making his own kept things simple, and the circuit has automatic gain control.

At this point, he added the MicroSD card adapter. Why not just transmit the audio over FM as so many others have done with their hacks? Perhaps he’s worried about someone detecting the transmission and finding his bug.

His final optimization involved getting a good battery life. He measured the circuit’s current draw at 20 milliamps. With a 160 mAh battery capacity, that would be 8 hours of recording time. Removing the Arduino Pro Mini’s voltage regulator and two LEDs got the current down to 18 milliamps and a recording time of 9 hours. Better.

Those are the highlights. Enjoy his full walkthrough in the video below.

Continue reading “Mini Spy Bug Walkthrough” →

Ride Bike, Charge Phone

February 8, 2018 by 49 Comments

Spring is coming to the northern hemisphere, and soon it’ll be nice enough outside to tool around town on your bicycle. But bikes don’t have power outlets, so phone charging on the go will require forethought and charged-up battery packs. It doesn’t have to be that way. You’re working to make the bike move, so why not make the bike work for you?

If you’ve ever used a motor as a generator, then you can see where this is going. That’s the underlying principle behind [Creativity Buzz]’s bike-powered phone charger. As the bike wheel turns, the rim comes in contact with a small wheel attached to the output shaft of a DC motor. Cranking the output shaft of a motor with permanent magnets inside will induce a small voltage, and here it is amplified with a DC-DC boost converter and output to a USB jack.

As long as you can find a way to secure the phone to the bike frame, or use a long cord and good cable management, you’re in business. Wheelie past the break to watch [Creativity Buzz] build it and give it a stationary test run. While you wait for bike-riding weather, you can still use this kind of charger by turning a crank.

Continue reading “Ride Bike, Charge Phone” →

Voice User Interface Design Practices

February 8, 2018 by 20 Comments

Websites used to be uglier than they are now. Sure, you can still find a few disasters, but back in the early days of the Web you’d have found blinking banners, spinning text, music backgrounds, and bizarre navigation themes. Practices evolve, and now there’s much less variation between professionally-designed sites.

In a mirror of the world of hypertext, the same thing is going to happen with voice user interfaces (or VUIs). As products like Google Home and Amazon Echo get more users, developing VUIs will become a big deal. We are also starting to see hacker projects that use VUIs either by leveraging the big guys, using local code on a Raspberry Pi, or even using dedicated speech hardware. So what are the best practices for a VUI? [Frederik Goossens] shares his thoughts on the subject in a recent post.

Truthfully, a lot of the design process [Frederik] suggests mimics conventional user interface design in defining the use case and mapping out the flow. However, there are some unique issues surrounding usable voice interactions.

Continue reading “Voice User Interface Design Practices” →

Count Your Fans With This Stylish ESP8266 Display

February 8, 2018 by 15 Comments

Continuous self-affirmation is a vital component to the modern lifestyle. Of course you know the world loves you, but exactly how much do they love you? Checking your phone every few minutes to see if you’ve gained any followers is gauche, and perhaps more to the point, doesn’t let you show off when you’ve got visitors over. In the modern era, the up-and-coming social media star needs a stylish way to display just how popular they are for the world to see.

That’s the idea behind this very slick social media counter created by [Becky Stern]. Built into a standard shadow box frame and using LED displays glowing through a printed piece of paper, the finished product looks more like modern art than the usual hacker fare.

The counter is powered by a NodeMCU, but you could drop in your favorite variant of the ESP8266 and things would work more or less the same. For the displays, [Becky] is using four Adafruit 7-Segment LED modules, which are easily controlled via I2C which keeps the wiring to a minimum.

It’s interesting to note that since her follower count on Twitter has already hit five digits, two of the display modules are used next to each other for that particular service. Her Instructables and Instagram counters only have one display each however, limiting her counts on those services to 9,999 each. There’s probably something to be learned here in terms of the relative follower counts you can expect on the different social networks if you’re targeting your content to the hacker and maker crowd, but we’ll leave the analysis to those with a better handle on such matters.

Hardware aside, [Becky] spends a lot of time in the video talking about the code she’s come up with to pull her stats from the various services and push them out to the LED displays at a regular interval. It’s nice to see so much attention and explanation given to the software side of a project like this, as more often than not you’re left to your own to figure out what the source code is doing.

This project is quite similar to the YouTube Play Button hack we covered a few months back, but the addition of multiple social networks in one device is a nice improvement over the basic concept.

Continue reading “Count Your Fans With This Stylish ESP8266 Display” →

Build A Tiny Hot Wire Foam Cutter

February 8, 2018 by 34 Comments

Let’s face it: cutting foam with a knife, even a serrated plastic knife meant for the job, is a messy pain in the ass.  This is as true for insulation board as it is for the ubiquitous expanded polystyrene kind of foam used for everything from coffee cups to packaging material.

Those stick-type hot wire cutters from the craft store that plug into the wall aren’t much better than a knife. The actual cleaving of foam is easier, but dragging a long, hot flexible wand through rigid foam just right, without making burn marks, is pretty frustrating. It’s not like you can hold the other end to keep it steady. A foam cutter built like a coping saw but held parallel to the wire would offer much better control.

[Techgenie]’s handheld hot wire foam cutter is a simple build based on a single 18650 and a piece of nichrome wire. While this is probably not the most Earth-shattering hack you’ll see today, it’s a useful tool that can be made in minutes with items on hand. Laptop chargers are full of 18650s, and nichrome wire can be sourced from old toasters, hair dryers, or space heaters.

You shouldn’t use just any old wire for this, though, or the battery will get hot and potentially explode. Nichrome wire has a high resistance, and that’s exactly what you want in a tool that essentially shorts a battery to make heat. [Techgenie] used a momentary button instead of a switch, which is a good way to stay safe while using it. It wouldn’t hurt to add some protection circuitry and take the battery out when you’re done. Burn past the break to watch him build it and cut a few tight turns with ease.

If you have bigger, more complicated foam-cutting jobs in mind, why not build a CNC version out of e-waste?

Continue reading “Build A Tiny Hot Wire Foam Cutter” →