Just a quick update on the state of Zulu. It's more or less finished (or on leave). I use it everyday and it works just fine! I've uploaded the code used for both the server and the app to my github. I also added new screenshots to the website. Go check it out and enjoy!
I’ll Say it’s a little important that you know how to work a dslr or at least manual mode on a camera and a little knowledge on wireless flash triggers or at least the concept of triggering a flash remotely from the camera. As far as skill goes, that’s pretty much it as this ‘instructable’ will cover whatever else you need to know.
There are mainly 2 methods to go about obtaining a similar result, both of which I’ve tried lots of times, namely manually timing the hit/crash/smash/sound/etc... And using a microcontroller to time it. I’ll start by describing the manual method then talk bout how to refine your success rate by involving microcontrollers.
You should know this requires LOTS of patience, the picture taking itself I got on the second try, the preparation and research(namely looking for plexiglass(which home-depot/lowes prefers it to be called acrylic glass)) is what takes a while. So be patient.
2. Parts Required
Cheap wine glasses.
>>>> I buy mine from dollar tree, $10 should get you 9 glasses(tax), it’s important they all look the same, so be careful when selecting them.
>>>> I personallyrecommend this onefor a cheap and easy solution if you’re getting started
A table (preferably ping pong)
>>>> One that can take a beating or won’t be the end of the world if it got some colored water or broken glass on it. It’ll be ideal to have a ping pong table, but if that’s not an option you could use a flat table that’s angled manually or have someone else start and stop your skateboard by hand.
You want to start by gluing the board to the plexiglass, I’m not a glue expert but I’m sure to get more contact surface points, it’s best for both surfaces to be rough. The skateboard already accomplishes that so I’ll advise you sand up 1 side of you plexiglass a bit. If this is a 1 time thing, you may also wanna use other stronger glues as hot glue did not particularly sign up for withstanding this much force and may let go, be prepared for that.
Next, the glasses themselves. You wanna glue these on the bottom and around the edges on the back of the glass(see picture). Again it helps to sand the bottom of the glass(be careful, ‘glass-sand’ can be dangerous). It makes sense to glue 1 glass on there skip to the paragraph begining with ‘test’ and check to see if it can withstand the amount of force it’s gonna go through. When gluing, be sure to evenly space them out and line them up as perfectly as possible.
Prepare your table( I have not real guidelines for how you’d accomplish this) but make sure if you’re using the paint cover, it’s on the floor BEFORE you place the table.
Colors! You’re at liberty to use whichever colors you may please, my only advice here is when diluted, blue and indigo are really hard to tell apart, I had to add quite a bit of saturation to purple, so you might just wanna fix that before taking the photo by using more purple dye per part.
Flash setup. THIS is the whole reason we can freeze the action. The flash’s flash duration(at low power at least) is often much shorter than the average DSLR’s shutter speed (1/32000 vs 1/4000). Since this isn’t a waterdrop picture, you can get away with 1/16th flash power, but remember, lower flash power = shorter duration of light = clearer picture(assuming it’s all in focus). I had a white backdrop with a flash lighting it from the bottom and two from each side.
You don’t really want to light the cups themselves as that’ll introduce reflections(and maybe glare) that’ll be a pain to remove. Lighting the background alone should be sufficient, as the like will simply pass through the liquid and the glass. You also wanna do this in a dark environment. The wireless triggers work here so you don’t have to have your camera tethered. I personally used a trigger on 1 flash and slave mode on the others, so that works too.
My settings were f4.5 1.3s @ ISO 250 with an 85mm lens. F4.5 because I needed/wanted extra sharpness, the long(1.3s ) shutter speed isn’t necessary but for using the Arduino and the path I took, it was. ISO 250 because it worked, and an 85mm lens because the compression helps give it the appearance of being zoomed in + the added benefit of little to no distortion but any lens will do, longer is better for this kind of applications, besides you don't want any water on your camera..
4. Picture Time !
Fill the cups in accordance to what you’re going for. I was going for a ladder of colors, and I simply put water proportionally in each cup, you could do the opposite, you can do 2 big spikes in the middle, all the same height, there are tons of ways to go about this.
Test with 1 glass, I found it necessary to test my system before gluing all 6 glasses, by just gluing 1, adding water and letting it go. The weak points you’d have to watch out for are the slender glass ‘legs?’ and the base glue(which will start coming off once it’s wet btw). You’d also wanna test your mechanism for letting it slide and making sure it’s a bit foolproof. If using an inclined slope, you might wanna add tissue or something to soften the impact as it makes it less likely something pops outta place and the table will be more likely to walk away without any scratched or dents
So when you’re ready, fill up your glasses and release (if inclined) or have a friend push the skateboard then pull back suddenly.
5. The Arduino/Automation
To improve my success rate I made a microphone circuit and wrote an Arduino program for it, thankfully you can get out of making a circuit and just get one on amazon(which I advise especially if you don’t want to solder). So you want to wire up the microphone to an analog input of your choice, then splice the camera and of the flash cable into 2 and hook one up to ground(on the Arduino) and the other to a digital pin. This is what’ll do the triggering of the flash.
DISCLAIMER – As an electrical engineer (-ing student) I must say this isn’t the safest way to go about this if you love your flash, it’s ideally best to use an optoisolator to isolate the current coming from your Arduino and that going to your flash, however I tried this and it didn’t work for you, your mileage may vary but be warned, it could fry your flash pin. That being said, I’ve taken 100’s of shots without one and all my flashes function perfectly.
Time to jump into the code. The code is quite simple and well commented but here’s the lowdown, it initializes everything, and starts a forever loop that reads the micValue and checks if it’s less than the threshold(it’s supposed to be greater but my circuit was backwards in a sense). If it passes the threshold level, quickly write 1 and write 0 then delay for about 1 second. The 1 second delay is so the flash doesn’t go off multiple times(i.e if the skateboard bounces back). Lines 31&32 are there for me to figure out the appropriate threshold levels, you don’t want it to be too high just as you don’t want it to be triggered by normal events such as talking. It gelps greatly if the mic is on the table as well as the vibrations from impact simplify things.