Spectacular View of the Eiffel Tower is all Done With Mirrors

What Parisian wouldn’t want an apartment with a view of the Eiffel Tower? Alas, not every window can face the famed landmark, and for some, the million Euro view is tantalizingly out of reach. Such was the case for [Lurluberlu], but with a little optical trickery he was able to peer around a corner to deliver spectacular views of the Eiffel Tower to his bedroom.

[Lurluberlu] devised a simple horizontal periscope using two full-length mirrors. The video after the break shows the build – as a side note, we’re very jealous of his hand tool packed workshop. With some plywood backing and simple swivels, the mirrors were mounted on his window sill to bounce the iconic tower’s image inside. After a little adjustment, the image is perfectly framed by the window, and with the lights off in the apartment, the view from the bed is quite spectacular. Our bet is that it’s quite a bit cheaper than moving to a flat with a better view.

Of course, with a little ingenuity (and a balcony) anyone can have a view of the City of Light. Or anywhere else for that matter.

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UV Laser Projector Shines With Glow-in-the-Dark Vinyl

Mirror galvanometers were originally developed in the 17th century to precisely measure very small changes in current. Unlike other instruments of the day, a mirror galvanometer could clearly show minute current variations by translating tiny movements of the mirror into large movements of the light reflected off of the mirror. Before clean electrical amplification became possible, this was the best means of measuring tiny differences in current. True mirror galvanometers are very sensitive instruments, but hobby servos can be used as a low-fidelity alternative, like with this project on Hackaday.io created by [robives].

Using a mirror galvanometer is by far the most common technique for laser projection shows – it’s really the only way to move the laser’s beam quickly enough to create the visual illusion of a solid line in real time. A mirror galvanometer works by using coils to attract magnets attached to the mirror, allowing the angle of the mirror to change when current is applied to the coils. This movement is extremely small, but is amplified by the distance to the projection surface, meaning the laser’s beam can move huge distances in an instance. If you’ve ever seen a laser show, it almost certainly used this technique. But driving galvos requires a beefy DAC, so we can’t blame [robives] for wanting to keep it digital.

[robives’s] project side-steps the need for galvanometers by using glow-in-the-dark vinyl and a UV laser. The result is a laser beam trail which lasts much longer, which means that solid lines are visible without the need for high-speed galvos. A build like this lets you experiment with laser projections without dealing with sensitive mirror galvos, and instead use components that you probably already have sitting on your workbench.

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Optics Laboratory Made From LEGO

16A lot of engineers, scientists, builders, makers, and hackers got their start as children with LEGO. Putting those bricks together, whether following the instructions or not, really brings out the imagination. It’s not surprising that some people grow up and still use LEGO in their projects, like [Steve] who has used LEGO to build an optics lab with a laser beam splitter.

[Steve] started this project by salvaging parts from a broken computer projector. Some of the parts were scorched beyond repair, but he did find some lenses and mirrors and a mystery glass cube. It turns out that this cube is a dichroic prism which is used for combining images from the different LCD screens in the projector, but with the right LEGO bricks it can also be used for splitting a laser beam.

The cube was set on a LEGO rotating piece to demonstrate how it can split the laser at certain angles. LEGO purists might be upset at the Erector set that was snuck into this project, but this was necessary to hold up the laser pointer. This is a great use of these building blocks though, and [Steve] finally has his optics lab that he’s wanted to build for a while. If that doesn’t scratch your LEGO itch, we’ve also featured this LEGO lab which was built to measure the Planck constant.

Interactive Fur Mirror Follows Your Every Move

We think artist [Daniel Rozin] spent a bit too much time wondering if he could make an interactive fur mirror, without wondering if he should. The result is… strange — to say the least.

It’s called the PomPom Mirror, and its one of many interactive installations in the Descent With Modification at Bitforms — there’s even a super cute flock of penguins which spin around to create the same effect.

The mirror is 4 by 4 feet and 18″ deep. It has 928 faux fur pom poms which are controlled by 464 motors, each effectively with an “on” and “off” state. A Microsoft Kinect tracks movement and creates a black and white binary image of what it sees. The artist also programmed in a few animation sequences which make the mirror come alive — like some weird furry alien / plant thing…

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Hackaday Tours Northrop: Space Telescopes and Jet Planes

I was invited to tour the Northrop Grumman Aerospace Systems campus in Los Angeles this spring and it was fantastic! The Northrop Grumman lists themselves as “a leading global security company” but the project that stole my heart is their work on the James Webb Space Telescope (JWST) for NASA. On the one hand, I don’t see how it could possibly be pulled off as the telescope seems to cram every hard engineering challenge you can think of into one project. On the other hand, Northrop (plus NASA and all of their subcontractors) has been doing tough stuff for a very long time.

How Do You Tour Northrop Grumman?

This opportunity fell in my lap since [Tony Long] is a Hackaday reader and an engineer at Northrop. He’s the founder of their FabLab (which I’ll talk about a bit later) and was so bold as to send an email asking if one of the crew would like to stop by. Yes Please!

I was already headed out to the Supplyframe offices (Hackaday’s parent company) in Pasadena. [Tony] offered to pick me up at LAX and away we went to Redondo Beach, California for an afternoon adventure.

James Webb Space Telescope: Everything Hard About Engineering

James Webb Space Telescope (JWST)

I had heard of the James Webb Space Telescope (JWST) but had never looked closely at the particulars of the project. Above you can see a scale model which Northrop built. I didn’t actually see this on my tour. It travels to different places, taking two semi trucks, with a dozen people spending four days to set it up each time. And that’s a not-real, relegated to the surface of the planet, item. What is it going to take to put the real one into space?

It’s not just going into space. It’s going to the second Lagrangian point. This is past the moon, about 1.5 million kilometers from the earth. If this thing breaks we can’t go out there and fix it. There’s a lot of pressure for success.

The main problem facing this satellite is heat. It will use a mirror array to harvest infrared radiation from very distant astronomical bodies. For this to happen it needs to have a very good optical array to gather infrared light and focus it on a collector, and it must be isolated from the heat of the sun, earth, and moon.

There is an array of 18 hexagonal mirrors which reflect the infrared onto a collecting mirror and in turn to the sensors. These mirrors are not made by Northrop, but they did have a prototype on display and it was incredible! Each mirror is made by Ball Aerospace out of beryllium. The concave surface is coated in gold for reflectivity and an actuator mounted on the back of each mirror can flex the surface to adjust the concavity and thereby the focal length. This is in addition to the ability to adjust the roll and pitch of each segment.

In the Northrop high bay they were working on the mounting system for these mirrors. It showed much more progress than the two images seen above. This is the central mount structure for the optics. The width of this structure is dictated by the size of the rocket which will launch it into space. When I saw it, folding wings had been added to either side of this main structure to host a dual-row of mirrors which are folded back into the telescopes during its storage position. The black material itself is a composite manufactured by Northrop. The cross-section they showed as an example was not much thicker than your fingernail but obviously quite rigid in the cast pipe shape.

You can see an animation of the unfolding process which was playing in the high-bay viewing room during the tour. Note the five-layer heat shield that needs to automatically unfold without snagging. This reminds me of [Ed van Cise’s] recollection of solar panel unfolding issues on the ISS. It’s a tough problem and it looks like much time has been spend making sure this design learns from past issues. That animation doesn’t show too many details about the mirror mechanics. I found video demonstrating how the mechanical part of the mirrors work to be quite interesting.

Learning more about what goes into the James Webb Space Telescope project is worth a lot of your time. I’m not joking about this including everything hard about engineering. The challenges involved in meeting the specification of this telescope are jaw-dropping and I’m certain the people working on the project across many different companies will make this happen.

Hackerspace Driving Corporate Culture


It was nice that [Tony] and his colleague [Adam] came right out and told me they reached out to Hackaday because they want to get the message out that Northrop is rejuvenating their corporate culture. They’re in the process of hiring thousands of engineers and part of this process is making the job fit with the lifestyle that these engineers want.

One big move in this direction is the formation of their FabLab. [Tony] is an engineer but 50% of his workload is tending to the FabLab. This is basically a hackerspace open to any of the roughly 20k employees at this particular location. Northrop fabricates amazing things, and when equipment is no longer used, the FabLab gets dibs on it. Imagine the possibilities!

unexploded-armament-removalPart of this initiative is to get more engineers learning about the fabrication process. [Tony] used the example of researching by fabricating a simple proof-of-concept in the FabLab. This is an avenue to that buzzword: fail-fast. Before getting your department on board with what might be a costly and time-consuming project you can test out some of the parts which are a little hazy in your mind.

The device seen here is the product of a challenge that one of the groups participated in last year. They had about six months to develop a robot which can clear unexploded armaments. It was hanging out in one part of the hackerspace and is a great build. You can just make out a blue sphere hiding in the underbody. That’s a huge jamming gripper powered by the black and yellow shop-vac perched atop the chassis. The robot is remote controlled, with wireless GoPro cameras mounted all around and underneath. Of course the thing wouldn’t be complete without a giant silver air-horn. Safety first!

It will be interesting to see if the FabLab can build the kind of grass-roots community often associated with standalone hackerspaces. You can get a glimpse at the grand opening of the space in this video. We don’t quite remember seeing a hackerspace marketed in this manner. But if that’s what it takes to get the company on board it’s well worth it. A huge space, amazing tools, and no monthly membership fee make for a sweet deal. Oh, and the name FabLab apparently came from their mascot, the Fabulous Labrador, who can be seen in the clip wearing a string of pearls.

F/18 Assembly Plant


We wrapped up the day by touring the F/A 18 E/F Super Hornet assembly line. This is a huge plant. I don’t know how to better describe the sheer size of the assembly line than saying it took no less than twenty minutes to walk back to the parking lot at the end of this tour.

00036301Northrop Grumman serves as the principal subcontractor for Boeing on this project, so the end of the line isn’t quite a fully assembled airplane. But the fuselage — less cockpit, nose, wings, and engines — is still a formidable sight. I’ve never been this close to a fighter jet before and the size is impressive. Equally impressive is the building housing the line, which was build in 1942 and is still wood-framed to this day. They have huge engineered columns which have since been reinforced with steel. But that fact makes it no-less impressive.

The top concern during assembly is FOD, or Foreign Object Detection. These vehicles are exposed to huge forces and vibrations that will shake anything that’s not supposed to be there loose, and that can mean horrible damage to an expensive machine or much worse. Some of the things I found really interesting were the systems in place to make sure no part goes missing. All components come in cases that have an individual cutout area for each. Tools are scanned to each employee, if broken or worn out there are vending machines throughout the plant keeping track of them through a computerized system.

As part of the tour we walked through the composites plant next door. There are massive autoclaves for curing the resins. These are like a pipe sitting on its side with hemispherical doors on each end. I’m a poor judge of time and distance but I’d estimate these to be 18 feet in diameter and at least 35 feet long. Traditional composite fabrication — a worker laying down sheets of carbon-fiber on a mold — were under way. But the room next door housed a robot that looked like it was born in The Matrix. The spider-like head works next to a turning mandrel fitted with the form of the piece being fabricated. It lays out about seven strands of carbon fiber, building up a part that has no seams whatsoever. After curing the resin the mold is removed manually, piece by piece, from the inside of the part. To me the parts being built looked like air intake channels approximately 15 feet long and maybe 5 feet in diameter, although they were winding and not exactly cylindrical in shape. I wasn’t able to get very many details about them, but I was told these parts are for the F-35 Joint Strike Fighter. This is another subcontract Northrop Grumman has for Lockheed Martin.


Thank you to [Tony Long] and [Adam Gross] for spending to give Hackaday this tour. I had the impression that I was living an episode of one of my favorite programs How It’s Made, and that was awesome! Northrop Grumman has an educational outreach program so if you’re associated with a school in the area set up a tour of the JWST!

[Tony] ducked out with me for dinner; some excellent tacos — a quest I’ve been on during each visit to LA. He joined me afterward on a trip to Null Space Labs for their open night. They had moved since the last time I was there and if you’re in town you should check it out.


One thing I should mention is that I was not able to take any photographs on the premises. My story above is original but all the photos are stock or provided by Northrop at my request.

Main Post Image via JWST Flickr

Front Mirror via YouTube thumb.

Extended Reflection Mirror via YouTube video.

Slick Bathroom Mirror is All Tricked Out

A Mirror surrounded by a string of brightly lit lamps is something you usually get to see in a Movie Star’s dressing room. [pickandplace] was inspired by the Movies, and a dark bathroom, to come up with a Bathroom Mirror equipped with some bells and whistles. To start with, his planning was quite detailed, sketching out the features and constraints for his design. He chose to use a round mirror with 12 LED bulbs (which are safer than 220V bulbs) so it can work as a clock. User input is handled by a motion sensor to automatically switch it on/off and a capacitive touch dimmer. Under the hood there’s an RTC (for clock and brightness adjustment based on time of day), simple boost PWM LED driver, thermal management for the LEDs which are 10W, temperature sensor to pipe down the current if the LEDs get too hot, and even an anti-fogging heater strip – phew!

His execution is no less brilliant. Starting with building the wooden frame and ending with the code for driving all the electronics. Along the way, you will find detailed notes on the LED’s, PWM Driver, Heat sinking, and capacitive Touch dimmer using Atmel’s AT42QT2160 Qslide – Matrix Sensor IC. He had some trouble with the Motion Sensor PIR module, and hasn’t yet written the code to implement it. His first version used a PIC18F87J50, and the next iteration had an ATXmega256A3BU – but he asks us not to get into the Microchip vs. Amtel debate. We have to agree on that. Sharp readers will point out that neither of the two micro’s can provide 12 PWM channels. Well, worry not, he has it all figured out. He also coded up a simple control interface which is handy when the unit is hooked up over USB to a computer. To top it off, he built a miniature LED ring to use as a “Simulator” while working on the code so he didn’t have to lug the heavy Mirror in and out of the bathroom. How’s that for doing a good job better! Source files are on his Github repo, and links to the hardware schematics are peppered throughout his blog.

If you don’t want to build something so fancy, look up the Bathroom Mirror with HUD which displays Time and Weather

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Infinity Mirror Clock: There’s a Time Joke There Somewhere

Infinity Mirror Clock

We don’t think we’ve seen an Infinity Mirror Clock before, but we love this new twist on an old favorite. Different colors distinguish between seconds, minutes and hours, and an additional IR sensor detects when someone is directly in front of the clock and switches the LEDs off, allowing it to be used as a normal mirror. This build is the work of [Dushyant Ahuja], who is no stranger to hacking together clocks out of LEDs. You can tell how much progress he’s made with the mirror clock by taking a glance at his first project, which is an impressive creation held together by jumbles of wire and some glue.

[Dushyant] has stepped up his game for his new clock, attaching an LED strip along the inside of a circular frame to fashion the infinity mirror effect. The lights receive a signal from an attached homemade Arduino board, which is also connected to a real-time clock (RTC) module to keep time and to a Bluetooth module, which allows [Dushyant] to program the clock wirelessly rather than having to drag out some cords if the clock ever needs an adjustment.

Stick around after the jump for a quick demonstration video. The lights are dazzling to watch; [Dushyant] inserted a stainless steel plate at the center of the circle to reflect the outer rim of LEDs. After a quick rainbow effect, it looks like the mirror enters clock mode. See if you can figure out what time it is. For a more step-by-step overview of this project, swing by his Instructables page.

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