Next night I went to a dog park up on Aurora. Last year I dated this girl, whose roommate can be charitably described as “socially maladjusted and less than pleasant to be around”. In an attempt to ease relationship a bit I tried a little bit of “BBQ diplomacy” by hosting a small BBQ and inviting her (the roommate) along. Well, the BBQ diplomacy failed – some people are just difficult and mean in nature – but I did get something positive out of that afternoon. The photographer in me realized that the parking lot had no street lights and thus would be a low-ambient place for light painting cars…

Here’s an ambient light only, 90 second exposure to give you an idea how dark the place is:

(The flash had slid off the hotshoe adapter, and thus refused to fire. It took me about a minute or so before I can get it reset, and by then I decided to stop the exposure to get a baseline.

Here’s with the SoftLighter up high:

And a bit of lightroom tweak:

For the most part I’m pretty happy with how these shots turned out. Moving forward, these would be the things I would try:

* Add a neutral density filter to the camera to further knock down the ambient
* Up the firepower of the strobes, probably to something along the lines of an Alien Bee
* Use a proper large softbox, to achieve more even lighting.
* Come equip with a better power source – maybe time to DIY a Li-Ion vagabond pack?
* Try flooding the asphalt to create a smoother surface for reflections.

By adding a neutral density filter, I should be able to find more places to be able to shoot from.

Got my spacer block that I designed a few months ago. Forgot to measure and account for the undercut ledge on the quick release plate. Will have to file / dremel it off for test fit, before I try mating a clamp up to it. Oh well.

Note to self – don’t design stuff when tired and depressed.

Our boss, who’s rarely wrong, always tell us that as design engineers, our time is the most valuable spent designing. “Whenever we need something, and need something quick, we just toss money at someone and have them bang it out and put it in a Fedex overnight box”.
My buddy Dave’s grandparents owns a laser engraver. They own a trophy engraving shop and laundromat down in Renton. It’s really wierd to think of a sweet old lady at the controls of an Epilog 20W CO2 laser system… but she doesreally good work. So the next time you need something engraved, check out the Puhich Dry Cleaners in Renton on 319 Main Ave. South.

I know what a 20W CO2 laser can do; it can do a lot more than mark plastic and burn through anodize layer on aluminum. There was a discussion thread on making lens cap holders, so I drew one up in Soldiworks real quick:

Here’s the test run in paper. So far so good, right?

Unfortunately, the laser engraver is running on Windows 98. It requires a firmware update before it can talk to anything past Win98, and there is always a risk of bricking a machine doing a firmware update. So we are stuck with a computer that works – abet a very slow one, with a parallel port printer connection. (I bet some of the folks I know had never seen one… they went the way of the dodo after USB became popular).

Complicating the problem is that the printer driver runs as a Corel Draw plugin. Corel Draw 8, to be exact. And even the earliest DXF that Solidworks can save the file in, the simple fillets on the drawings don’t quite come through – let alone the more complicated splines and polylines.

The example above worked okay, because the laser cut it out as a *Raster* art, instead of a vector art. But cutting in raster mode drastically drops the laser’s power output. And it’s not like you can run multiple passes over the same piece of PTFE either – the slow heat transfer of doing so just warps the plastic – and the results looked like someone tried cutting the material with a dull butter knife.

Obviously something like this, out of 3mm PMMA, will be a bit out of the question:

So my options are:

1) Try to mitigate the risk of the current laser cutter’s firmware upgrade (maybe see if I can do a hardware replacement of the logic board, upgrade the computer to something snazzy, then retry the Solidworks -> laser cutter workflow.

2) Pay someone like Pololu online to do the laser cutting for me. Essentially, someone else will be eating part of my lunch if these products go on sale. Might be okay if there’s only a few parts, but I’ll have to rethink the design a little bit.

Turns out, RedWolf airsoft out of Hong Kong will happily sell me a 30mm silencer for about $US10.00. Aluminum barrel, both ends with a machined aluminum plug. They even put a 14mm CW thread on one end and 14mm CCW threads on the other, so out of the box, the dang thing will fit on just about every single airsoft gun out there.

In Hong Kong, we have a saying that “the flour costs more than the bread”. The term originated from the housing bubble days where the value of the land gets bid up so quickly that older apartment buildings prices are being outstripped by the land value of neighbouring lots, but it also applies to engineering and business where by some form of competitive advantage (and economies of scale), someone can build a product cheaper than you can even start sourcing raw materials.

Got a cool little bookmark for all my troubles with the laser cutter though…

Andy’s hacked LED flashlight (the man stuck an 18650 Li-Ion cell inside a $2.99 keychain LED flash. God that thing is bright) worked pretty decently in the previous light painting exercise, so I figured I’d up the fire power. Ran to Harbor Freight during lunch and picked up a 1 million candlepower flashlight for $12.99.

First try was to set the camera’s white balance to tungsten (since that’s what flashlights are), camera on a tripod, f/8, ISO100, bulb mode, and lock the shutter open in a dark room. For the sake of learning, I painted one side of the car at a time:

Here’s the front of my car

And the sides:

And here’s the combined shot:

There is some spillage of the light cone. Basically the parabolic reflector throws a pretty tight beam spot, but there’s some secondary reflection / refraction off the front lens cover that’s lighting up stuff I don’t care to light up.

A quick trip to the mail room for an envelope or two, and a bit of packaging tape, solved that problem:

Results:

Next, I set up my Photek softlighter with the secondary diffuser, and hoisted it up high on my light stand. I really need a sturdier stand, or something with a counterweight to help hold this up. By lighting from up high, I am hoping to eliminate the hot spot on the bodywork. Something to do with family of angles and stuff. .

HEY! This is pretty good. Of course, a softbox is kinda like a shotgun approach to lighting, but at least there’s a choke in this shotgun barrel.

One thing to note (if you zoom in on the original) is that the light stand holding up the Photek Softlighter is visible in the shot. It’s being back-lit by the softlighter, and shows up as black lines in the reflections in the window.

I fixed this by installing the diffuser the “wrong” way. Normally I don’t do this, as it eliminates the ability to tilt the softlighter and blocks off the flash’s controls, but for what I’m doing here, it solved my problem nicely:

I moved the car to shoot the driver’s side. While there, I also popped just the hazard lights by themselves, to give an idea of their contribution independently in the final image:

With the “gimpy” configuration on the softlighter, I retry the overhead lighting:

Not bad, but the sides are a bit dark. By the way, the strobe is at M1/16 and I’m firing 2-3 shots per second while slowly walking down the side of the car. Essentially turning my 60″ photek into a virtual, 8ft x 60″ strip lighting softbox. That’s powered by 4x AAs

Another shot, this time using a 70-200 for a tighter crop and less background clutter:

Looking nice. Need to do something about lighting the front surfaces though.

Here, after lighting the top and across the hood, I walked sideways across the front and held the softbox out to the side, aiming straight at the car.

Ooops, ended up in the camera’s field of view. The edge of the photek lights up from secondary bounce; so I have to be extra careful. The next time around I’m going to try to find a proper softbox, and probably put a cardboard grid on it to control the spread more.

Now that I have a better understanding, I reshoot the sequence, being mindful to stay outside the camera’s field of view at all times with the side firing softbox:

Straight out of camera, vantage point 1

Straight out of camera, vantage point 2

To get the camera low enough for the second shot, I twisted the Manfrotto tripod around like a pretzel:

And with a bit of editing in Lightroom:

The only mistake? I got into the car to flick on the hazards, HID lights and fog lights. The suspension reacted accordingly, so there is a mismatch where the side turn indicator lit up, versus where the indicator lamp sat during nominal exposure. Nuts.

I think I’m at the point where I’ve outgrown this warehouse – the white walls really distract from the final image, but it offered me a nice, warm and dry place to practice my light painting. By the way, here’s a behind the scene shot of the “studio”:

Total time: About 3 hours, after work, for about 20 images. And a lot of head scratching.

Now, I need to location scout for an outdoor place that’s got low ambient light…

So, when I found out that there’s an empty warehouse I have access to, I took the opportunity to do some car light painting. It’s very hard to find a place where I can (mostly) control my ambient lighting to light paint a car.

Here’s my “weekend car”, the Spirit of Adventure, named after the airship in Pixar’s “Up”. (My coworker’s daughter commented that I reminded her of Russell… and I plan on taking this car on multiple photography adventures in the years to come, so I figured it’d be a fitting name). She’s a 2009 Mazda Premacy / Mazda5 Grand Touring with HID headlights and a few high tech refinements in the works.

With the overhead florescents on, we are looking at about a 3 second exposure at f/11 @ ISO 100.
Of course, this gives us a picture of a car in an empty warehouse. Hardly exciting.

Next, I turned the garage lights off, and walked around the car popping an AlienBees Ring Flash at 1/32 power at the car. Just a real quick multi-pop job. The diffuser is on the ABR.

Ringflashes, with a diffuser, is really good at throwing light EVERYWHERE. And I mean, EVERYWHERE. Aside from reflecting in ugly splotches on my car’s body work, it lit the entire warehouse up.

Next, i tried using my Photek Softlighter with the ABR. This gives me better control over the bounce. Unfortunately, the ABR’s umbrella adapter attachment is really badly designed, and the umbrella collapsed under its own weight. By some miracle the ribs collapsing onto the unit didn’t shatter the flash tube (the ABR actually belongs to my ex-girlfriend, whom I haven’t seen since our breakup – and I still would like to be friends with this girl…). Needless to say, the umbrella came off after that.

And just to see what a ring flash from the camera’s perspective would look like, here’s the ABR800 @ full power, single shot:

Note the tale-tale ring of shadow on the wall behind the vehicle.

Frustrated, I knew that I could create a nice big and soft light source by firing the ABR at full power at one of the white walls. This lit my car evenly. It also lit the rest of the warehouse evenly.

Then it dawned on me to try a different light painting technique – with a flashlight. I grabbed one of the LED flashlights off a coworker’s desk, and gives it a try. (I really need to redo this with a bigger throughput flashlight, but for now I’m working with what I’ve got).

Hey! Not bad! I should put a lens hood-like device on the flash light to prevent spill from the flashlight from being picked up by the lenses. During this exposure I also got into the car and flicked on the headlights and hit the hazard lights briefly – thus the fog lights and such being on. I also made a point to hover a bit longer at the wheels with the LED flashlight to make the wheels pop more.

Note the significantly longer exposure – the LED flashlight is pretty weak sauce, compared against an ABR800, even at 1/32 power. The ambient sodium vapor light coming in through the skylight above the door is really making its presence known on the wall behind the car, as is just ambient streetlight that’s coming through the blinds.

Tried another shot – this time I kept the flashlight relatively steady and slowly walked down the side of the car, being mindful of the specular highlight on the bodywork as the light traces its way down the panels. (Note to self – avoid the door handles next time – they tend to reflect light all sorts of wierd way). Again, same trick with the hazards – this time I used my keyless entry to get the lights to flash.

Finally, some adjustments and cropping in Lightroom, to give the following images:

A tight crop, with the “psychotic” lighting lines down the side”

And a “safe” shot.

For my next series, I’m going to try to light from a higher vantage point (bring a ladder). Better nail this with my Mazda and my Honda before I go grab MikeZ’s EVO-X …

Came across this priceless video of the current Macau SAR’s chief executive, Mr. Fernando Chui, being sworn in. His Mandarin is unbearably bad, so some prankster had taken the liberty and subtitled it with just about the worse words one can use, given his mispronunciations. So he’s shown essentially in the video talking about fecal matter, pants not fitting, and a sick Dad frying cheese – to the Chinese President Hu Jin Tao.

My mandarin isn’t perfect, but if I’m the chief executive, I’d at least learn how to say my own name, the place I’m running, and the place I report to correctly.

And on the note of good Mandarin speaker, here’s a clip of the Australian PM Kevin Rudd at APEC2007.

Boys with Toys

Came across Vrogy’s photo stream on Flickr. What do you do when you mix a CAD guy, a CNC mill and a cosplaying geek? A website where you can download Solidworks model of the Halo3 sniper rifle, among other things.

And speaking of boys and projectile weapons, here’s an old video of a Rufus Hussey, the “Bean Shooter Man”. Mr. Hussey passed away in the 1990s, so this must be (judging from the Pepsi cans) quite an old video.

And here’s a modern day German guy by the name of Joerg Sprave that designs some really out of this world slingshots, complete with compound ball bearings and load balancing yokes.

It’s a cool event – our little crew had been featured on Strobist.com, YouTube videos, and Chase Jarvis’s video blog.

Here’s an outfit that Emily wanted to be photographed in. The moment the sunglasses went on, I knew I was in trouble. The curvature of the sunglasses, coupled with the mirror surface, meant that there’s really no way to hide the light source in the final image.

When I see a mirror surface like that, I know I have to create a large enough light source to try to fill the family of angles that the mirror surface will reflect. So I moved Emily away from the white wall that I was shooting her against, and used that as a reflector for my two flashguns. Note that now I’m between the wall and the subject and is backlit in the shot above.

To make myself easier to remove from the image, I took the secondary diffuser fabric from my Photek Softlighter, and poked the camera lens through it. Now, I can “camoflage” myself underneath the Photek’s diffuser:

Much better. The light thrown by the wall also lights up the softlighter’s diffuser, which makes me that much easier to remove.

A little bit of touch-up in lightroom (edit brush, +4EV exposure comp) and we are left with the final image:

(and this is now her facebook profile image, so I know I did something right ).

Additional Resources:
Seattle Flickr Meetup Group [Discussion forum | Meetup.com Webpage]
Strobist.com – to learn more about off camera lighting

Mujahid Abdulrahim at the University of Florida has an SAE white paper on the sports of drifting:

Same dude also has 1000fps footage from a Phantom High Speed camera of Mini-Z racers crashing on YouTube. What a cool guy.

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TechRestore has a cool series of stop-motion photography of various gadgets being unboxed, disassembled and reassembled. Here’s one of the iPhone 3GS going under the knife. They have a behind the scenes look at how these are done here.

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Tormach CNC has a really innovative tool in beta – combining a USB microscope with a CNC mill. It’s part vision based CMM, part machine setup tool. The last part is key – you can reverse engineer a part, and machine a new part using the same tool to setup / reference features already on an existing part.

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Food:

Garett Kern, of Garett’s Table, has a totally out of this world take on the classic Peanut Butter and Jelly Sandwich.

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Food Pairing is an awesome website for exploring different food pairing options.

Tonight, the goal was to test the breadboarded prototype of the bullet flight sensor’s electronics. Remember – I am a mechanical engineer; this is a completely new foray into the world of electronics for me, aside from some simple “hook a solid state relay to a microprocessor and bit bang some code to turn on the rice cooker” projects. So even though this may seem like kindergarden EE stuff, it’s a fairly big leap for me, design wise; I’m no longer relying on the ability to clobber code and instead using discrete logic ICs and doing actual calculations and setting RC time constants, etc.

We begin with the breadboarded model:

And our setup in the lab:

On the bench is a trusty oscilloscope to look at the signals at different lines, a DC power supply set to 5V, 100mA current limit, and a signal generator. The signal generator won’t be used for this project here.

First, I verified that the *new* sensor is working – the last one had a round put through it by accident:

Next, I verified that the 555IC is getting the power that it needs. Turns out that the power rails aren’t fully connected all the way. A bit of poking with an ohm-meter fixed that. Now I am ready to insert my test points:

And trip the break-beam sensor, with my gimpy fingers:

Orange line, or Ch1, is my sensor’s output. It goes from High to Low when the beam is broken. The turquoise line, or Ch2, is my 555’s trigger output. It goes from low to high when the input pulse is received. That’s a VERY promising sign.

My fat butter fingers can only move so fast through a 10mm opening, so the event scrolls off the oscilloscope’s screen. I tried dropping a small machine screw through the opening, but that actually prove to be much harder than expected (don’t laugh!). Frustrated, I finally came up with the following idea:

By flexing the rubber ducky antenna on one of my pocket wizards and getting it to spring through the break-beam sensor gap, I can generate a quick enough blip from the sensor:

Each major division is 5 milli-second on this setting, so the rubber ducky antenna is only in the beam’s path for about 10mS. My fingers can’t move *that* fast, for sure

Repeating the test again a few times, got me the same result:

Note that irregardless of the pulse length from the sensor, the 555’s output always sits at about 35ms. This is a litte bit off from the design goal of 40ms (1/250 second shutter speed, or sync speed on a 1.6x crop camera), but close enough for government work. I attribute the difference in component value tolerances on setting the RC constant.

Now the final test – does the output from the 555 trip the SCR to fire the strobe and pocket wizard?
(I selected an SCR instead of a cheaper / more common transistor. The SCR is rated to 400V, so even an older, high voltage “digital camera killer” flash will work on this sensor. )

And…

*drum roll please*

Nothing happened.

Turns out the same bug that bit me on the 555 timer bit me again. The top and bottom half of the power bus on this breadboard is not connected, and the SCR wasn’t grounded properly because of that. Now, plugging in a pocket wizard, this is what I get (with Ch2 now monitoring the anode of the SCR):

Interesting, it seems to add a bit of noise to the sensor output line. But the characteristic beep of the PW firing can be heard as the beam is broken. (Note that the sync voltage of the pocket wizard is only 3V or so).

Plugging in the 580EXii:

Again, some electronic noise on the sensor line, but we got what we need out of it – the clean voltage drop that triggers the monostable multivibrator.

And here’s the happy camera dork with his new toy (click link for video:)

Now that the circuit is verified working, I am okay with releasing the resources to order the acrylic for laser cutting to form the chassis, as well as starting PCB layout. Stay tuned…