[Ben Krasnow] Hacks a Scanning Electron Microscope

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[Ben Krasnow] is quite possibly the only hacker with a Scanning Electron Microscope (SEM) collection. He’s acquired a JEOL JSM-T200, which was hot stuff back in the early 1980’s. [Ben] got a great deal, too.  He only had to pay shipping from Sweden to his garage. The SEM was actually dropped during shipment, but thankfully the only damage was a loose CRT neck plug. The JSM-T200 joins [Ben's] homemade SEM, his DIY CT scanner, the perfect cookie machine, and a host of other projects in his lab.

The JSM-T200 is old tech; the primary way to store an image from this machine is through a screen-mounted Polaroid camera, much like an old oscilloscope. However, it still has a lot in common with current SEMs. In live video modes, an SEM can only collect one or two reflected electrons off a given section of a target. This creates a low contrast ghostly image we’ve come to associate with SEMs.

Attempting to fire more electrons at the target will de-focus the beam due to the electrons repelling each other. Trying to fire the electrons from higher voltages will just embed them into the target. Even SEMs with newer technology have to contend with these issues. Luckily, there is a way around them.

When “writing to photo”, the microscope switches to a slow scan mode, where the image is scanned over a period of a minute. This slower scan gives the microscope extra time to fire and collect more electrons – leading to a much better image. Using this mode, [Ben] discovered his microscope was capable of producing high-resolution digital images. It just needed a digital acquisition subsystem grafted on.

Click past the break to see how [Ben] modernized his microscope!

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[Ben Krasnow] and His 8 kJ Ruby Laser

 

We were again pleased to find another person who attended Maker Faire just to show off the awesome and not to hawk some goods. In our mind [Ben Krasnow] represents the highest echelon of hardware hacking (apparently Google[x] agrees because they just snatched him up) . But [Ben] always makes a point to explain how he does what he does so that others may learn and someday achieve a similar type of greatness. This time around it’s a functional ruby laser which is backed by a capacitor bank that stores a whopping 8 kilojoules of energy. This is what allows the laser to cut through steel plate. He sure has come a long way since he first showed off the project in January.

Unfortunately we didn’t get to [Ben's] booth until late on Sunday. His previous demonstrations burned through some seals and left him with a non-functional laser. But he’s a trustworthy guy so we believe him and look forward to him posting a video about the laser and hopefully about the failure. He also mentions that he may make an attempt at lunar laser ranging with this device; bouncing the laser off of reflectors on the moon and measuring the delay. This can then be used to calculate the distance to the moon.

By the way, it was super difficult not to crack a joke when he says the words “Ruby Rod“.

[Ben Krasnow] Did It All For The (Perfect) Cookie

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[Ben Krasnow] is on a mission. He’s looking for the perfect chocolate chip cookie. To aid him in this noble endeavor, he’s created the cookie perfection machine. From cleaning with plasma, to a DIY CT scanner, to ruby lasers, to LED contact lenses, [Ben] has to be one of the most prolific and versatile hackers out there today. What better way to relax after a hard day of hacking than to enjoy a glass of milk and a perfect chocolate chip cookie?

This is actually an update to the machine we first saw back in 2012. [Ben] has loaded his machine up with ingredients, and has everything under computer control. The machine will now dispense the exact amount of ingredients specified by the computer, measured by a scale. Everything happens one cookie at a time. The only downside is that the machine doesn’t have a mixer yet. [Ben] has to mix a single cookie’s worth of dough for every data point. His experiments have returned some surprising results. Too little flour actually results in a crisper cookie, as the wetter dough spreads out to a thinner layer. [Ben] also found that adding extra brown sugar also doesn’t result in a more chewy cookie. Even though he’s still in the early experimentation phases, [Ben] mentions that since it’s hard to make a bad chocolate cookie, even his failures taste pretty good.

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[Ben Krasnow] Explains Kilowatt Hour Meters

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[Ben Krasnow] is back, and this time he’s tearing down a kilowatt hour meter (kWh). While not as exciting as making aerogel at home, or a DIY scanning electron microscope, [Ben's] usual understated style of explaining things makes a complex topic simple to digest.

These old mechanical meters have been a staple on the sides of houses and businesses since the dawn of commercial power. We always thought the meters were a basic electric motor. Based upon [Ben’s] explanation though, these meters are a complex dance of electromagnetic fields. Three coils create magnetic fields near an aluminum disk. This creates eddy currents in the disk resulting in a net torque. The disk spins, turning a clockwork and advancing the dials.

Why three coils? One is a high turn high gauge voltage coil, and the other two are low turn low gauge current coils. The voltage coil has to be phase shifted 90 degrees to create the proper torque on the disk. Confused yet? Watch the video! [Ben] does a much better job explaining the field interactions than we could ever do in text.

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Team Van Gogh uses OpenXC to create art from your drive

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In this video, [Joe Grand] takes us through [Team Van Gogh’s] entry in the OpenXC hackathon event. In what could possibly be the greatest road trip in history, [Joe Grand, Ben Krasnow, TechNinja, and Super Awesome Sylvia] all pile into a car. With them they bring a host of dev boards, wires, a CB Radio, and of course Sylvia’s WaterColorBot.

As their name implies, [Team Van Gogh] took a more artistic approach to the challenge than other teams.  OpenXC steering, gear shift, accelerator and brake data is sent through a ChipKit to an RS-232 link into [TechNinja’s] laptop. The laptop translates the data into commands for the WaterColorBot. With this system, a simple Sunday drive can become abstract art.

The team also showed the concept of what could be done if OpenXC was extended to send data back to the vehicle – something Ford doesn’t support. Their example works when a phone call comes in by using the system to lower the volume on a CB radio standing in for car’s Bluetooth system.

Most of this challenge was completed with simulated data from the OpenXC vehicle interface. The team only had a few minutes to work the bugs out in a real vehicle. However, they proved their concepts well enough to win the grand prize.

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Polishing optics milled from acrylic

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[Ben Krasnow] milled some lenses out of cast acrylic and needed a way to get an optical finish on the tool-marked surface. He tested several acrylic finishing methods to achieve a crystal clear finish. The tests were done using flat chunks. A regiment of sandpaper, from coarse to fine, was used as the first stage of the operation. From there [Ben] sought out the best finishing step, starting with hand polishing tests, flame polishing, and methylene chloride vapor polishing (which is something along the lines of acetone vapor polishing for 3D printed ABS parts).

Flame polishing and vapor polishing are not really exact sciences… at least in the tests he performed. It was difficult to know exactly how long to expose the acrylic. Too short or too long resulted in poor clarity. Watch his video to get a look at all results. We’d say the the easiest way to make milled acrylic clear without achieving an optical finish is to flame polish it as it doesn’t really require that you sand it ahead of time. But [Ben's] tests prove that you can’t beat hand polishing with 600 then 2000 grit sandpaper before finishing up with a liquid plastic polish.

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Hybrid rocket engine uses acrylic as fuel

We are fascinated by the hybrid rocket engine which [Ben Krasnow] built and tested in his shop. It is actually using a hollow cylinder of acrylic as the fuel, with gaseous oxygen as an oxidizer. We’re already quite familiar with solid rocket propellant, but this hybrid approach is much different.

When a rocket motor using solid propellant is lit it continues to burn until all of the fuel is consumed. That is not the case with this design. The acrylic is actually burning, but if the flow of oxygen is cut off it will go out and can be ignited later. This also opens up the possibility of adjusting thrust by regulating the pressure of the oxygen feed.

[Ben] milled the test rig in his shop. It’s a fat acrylic rod through which he bored a hole. There are two aluminum plates which complete either end of the chamber. The intake has a fitting for a valve which connects to the oxygen tank. There is a nozzle on the outflow end. Check out the video after the break to see a full description. You’ll also get a look at the toll the combustion heat takes on the rig.

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