Electron Beam Control In A Scanning Electron Microscope

Electron

A few years ago [Ben Krasnow] built a scanning electron microscope from a few parts he had sitting around. He’s done a few overviews of how he built his SEM, but now he’s put up a great video on how to control electrons, focus them into a point, and scan a sample.

The basic idea behind a scanning electron microscope is to shoot electrons down a tube, focus them into a point, and scan a conductive sample and detect the secondary electrons shot off the sample and display them on an oscilloscope. [Ben] is generating electrons with a small tungsten filament at the top of his electron ‘stack’. Being like charged, these electrons naturally fan out, so a good bit of electron optics are required to get a small point.

Focusing is done through a series of pinholes and electrostatic deflectors, much like you’d see in an old oscilloscope CRT. In the video, you can see [Ben] shooting electrons and displaying a Christmas tree graphic  onto a piece of phosphor-coated glass. He has a pretty big scanning area in his SEM, more than enough to look at a few chips, wafers, and whatever other crazy stuff is coming out of [Ben]’s lab.

Video below, along with the three-year-old overview of the entire microscope.

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A Virtual Cane For The Visually Impaired

[Roman] has created an electronic cane for the visually impaired. Blind and visually impaired people have used canes and walking sticks for centuries. However, it wasn’t until the 1920’s and 1930’s that the white cane came to be synonymous with the blind. [Roman] is attempting to improve on the white cane design by bringing modern electronics to the table. With a mixture of hardware and clever software running on an Android smartphone, [Roman] has created a device that could help a blind person navigate.

The white cane has been replaced with a virtual cane, consisting of a 3D printed black cylinder. The cane is controlled by an ATmega328 running the Arduino bootloader and [Roman’s] code. Peeking out from the end of the handle is a Maxbotix ultrasonic distance sensor. Distance information is reported to the user via a piezo buzzer and a vibration motor. An induction coil allows for charging without fumbling for tiny connectors. A Bluetooth module connects the virtual cane to the other half of the system, an Android phone.

[Roman’s] Android app runs solely on voice prompts and speech syntheses. Navigation commands such as “Take me to <address>” use the phone’s GPS and Google Maps API to retrieve route information. [Roman’s] app then speaks the directions for the user to follow. Help can be summoned by simply stating “Send <contact name> my current location.” In the event that the user drops their virtual cane, “Find my device” will send a Bluetooth command to the cane. Once the command is received, the cane will reveal its position by beeping and vibrating.

We’ve said it before, and we’ll say it again. Using technology to help disabled people is one of the best hacks we can think of. Hackaday alum [Caleb Kraft] has been doing just that with his work at The Controller Project. [Roman] is still actively improving his cane. He’s already won a gold medal at the Niagara Regional Science and Engineering Fair. He’s entered his project in several more science events, including the Canada Wide Science Fair and the Google Science Fair. Good luck [Roman]!

Play Peek-A-Boo With Blind Spot

blindspot

You’re at a concert, and a car filled with balloons is in a glass box. As you approach the box, vertical blinds close to block the view directly in front of you. You move left, more blinds close to block your view. The blinds follow your every move, ensuring you can’t get a close up view of the car inside. You’ve just met Blind Spot, an interactive art installation by [Brendan Matkin].

Blind Spot was presented at Breakerhead, an incredible arts and engineering event which takes place every September in Calgary, Canada. Blind Spot consists of a car inside a large wooden box. Windows allow a view into the box, though there are 96 vertical blinds just behind the glass. The vertical blinds are individually controlled by hobby servos. The servos are wired to six serial servo controllers, all of which are controlled by an Arduino.

A PC serves as Blind Spot’s brain. For sensors, 6 wide-angle webcams connect to a standard Windows 7 machine. Running 6 webcams is not exactly a standard configuration. To handle this,  [Brendan] switched the webcams to friendly names in the windows registry. The webcam images are read by a Processing sketch. The sketch scans the images and determines which of the 96 blinds to close. The code for Blind Spot is available on github.

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Super Mario On A Human-Machine-Interface!

super mario

Getting Super Mario to work on your TI-83 calculator is almost a rite of passage for young geeks, so we really liked this project where [Chad Boughton] managed to get it running on a PLC’s HMI screen instead!

He’s using a Danfoss DP600LX microcontroller with an HMI display along with a CAN bus joystick. This kind of equipment is typically used to control hydraulic systems, as well as display sensor data — [Chad] was curious to see if he could do animation with it as well — it looks like he’s succeeded! The funny thing is we’ve seen those “joysticks” before and it’s cool to see them used for something like this — like [Chad] said, they’re normally used for actuating hydraulic and pneumatic cylinders.

Stick around after the break to see Mario eat some mushrooms.

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Gesture Recognition Using Ultrasound

SAMSUNG

You’d be hard pressed to find a public restroom that wasn’t packed full of hands free technology these days. From the toilets to the sinks and paper towel dispensers, hands free tech is everywhere in modern public restrooms.

The idea is to cut down on the spread of germs.  However, as we all know too well, this technology is not perfect. We’ve all gone from sink to sink in search of one that actually worked. Most of us have waved our hands wildly in the air to get a paper towel dispenser to dispense, creating new kung-fu moves in the process. IR simply has its limitations.

What if there was a better way? Check out [Ackerley] and [Lydia’s] work on gesture recognition using ultrasound. Such technology is cheap and could easily be implemented in countless applications where hands free control of our world is desired. Indeed, the free market has already been developing this technology for use in smart phones and tablets.

Where a video camera will use upwards of 1 watt of power to record video, an ultrasound device will use only micro watts. IR can still be used to detect gestures, as in this gesture based security lock, but lacks the resolution that can be obtained by ultrasound.  So let us delve deep into the details of [Ackerley] and [Lydia’s] ultrasound version of a gesture recognizer, so that we might understand just how it all works, and you too can implement your own ultrasound gesture recognition system.

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Rebuilding A 50,000 Volt Power Supply

Spark

The theory behind building power supplies is relatively easy, but putting it into practice and building a multi-kilovolt supply is hard. A big transformer in air will simply spark to itself, turning what could be something very cool into something you just don’t want to be around. [glasslinger] over on YouTube is an expert at this sort of thing, as shown in his 50,000 Volt power supply build. That’s a 55 minute long video, and trust us: it’s worth every minute of your time.

[glasslinger] began his build by taking an old 15,000 Volt neon sign transformer and repurposing the coils and cores for his gigantic 50,000 volt transformer. There was a small problem with this little bit of recycling: the neon sign transformer was potted with tar that needed to be removed.

To de-pot the transformer, [glasslinger] made a small oven from a helium tank, melting all the goo out with an old school gasoline torch. From there, hours and hours of cleaning ensued.

The transformer cores were cleaned up and cut down, and a new primary wound. A small-scale test (shown above) using the old secondaries resulted in a proof of concept with some very large sparks. The next step was putting the entire transformer in a box and filling it with transformer oil.

The money shot for this build comes when [glasslinger] assembles his transformer, rectifier, and all the other electronics into a single, surprisingly compact unit and turns standard wall power into a 50,000 Volt spark. You can literally smell the ozone from the video.

 

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This Machine Sucks Balls

The best career choice anyone could ever make – aside from the richest astronaut to ever win the Super Bowl – is the designer of the kinetic art installations found in science centers that roll billiard balls along tracks, around loops, and through conveyors in a perpetual display of physics and mechanics. [Niklas Roy] isn’t quite at that level yet, but he has come up with a new twist on an old idea: a machine that literally sucks balls from a ball pit into transparent tubes, sending them whizzing around the installation space.

The installation consists of eighty meters of plastic tubing suspended in the staircase of Potocki Palace in Kraków. Electronically, the installation is extremely simple; a PIR sensor turns on a vacuum cleaner whenever someone is in the ball pit. This sucks balls up through a hose, around the space, and into a bin suspended over the pit. Pull a lever, and the balls stored in the bin are dispensed onto the person vacuuming up thousands of balls below.

Image source, with video below.

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