Simple Photo Flash Trigger For Water Balloon Photography

Water Balloon Photography

There have been countless projects to make custom photo flash trigger circuits. Usually the circuits react to sound, triggering the camera flash at the moment a certain sound is triggered. That type of trigger can be used to detect the popping of a balloon or shattering of glass. Other triggers detect motion, like a projectile crossing a laser beam for example. [Udo’s] friend had a fun idea to take photos of water balloons popping. Unfortunately neither of those trigger methods would be well suited for this situation. That’s when [Udo] had to get creative.

[Udo] built a unique trigger circuit that uses the water inside the balloon as the trigger. The core component of the circuit is an Arduino. One of the Arduino’s analog pins is configured to enable the internal pull-up resistor. If nothing else is connected to the pin, the Arduino will read 5 volts there. The pin is connected to a needle on the end of a stick. There is a second needle on the same stick, just a short distance away from the first. When these needles pierce the balloon’s skin, the water inside allows for a brief moment of conductivity between the two pins. The voltage on the analog pin then drops slightly, and the Arduino can detect that the balloon has popped.

[Udo] already had a flash controller circuit. He was able to trigger it with the Arduino by simply trying the flash controller’s trigger pin to one of the Arduino’s pins. If the Arduino pulls the pin to ground, it closes the switch on the flash controller and the flash is triggered. Both circuits must share a common ground in order for this to work.

All of the code for [Udo’s] project is freely available. With such spectacular photographs, it’s only a matter of time before we see more of these floating around.

33 thoughts on “Simple Photo Flash Trigger For Water Balloon Photography

    1. What’s a transistor? I did this in the 70’s with a piece of tin can and a nail with some wire and a thread. The thread is taped to the balloon and when the balloon contracts it pulls the thread and closes the switch (pulls strip of metal against nail). Wires were across the trigger on a Strobonar I borrowed from someone. Worked great. Adjust timing with the amount of slack in the thread.

      Gotta say though I never thought of the long balloons around a subject. Very nice effect.

      1. What’s a tin can and a nail? I did this with some hydraulic surge problems in the early 80s by simply having the shock machine (made of machined aluminum) traverse a protruding wire. What I didn’t know at the time is that the cheap strobe I was using was too slow to really give us what we needed. That and waiting to develop the (#*%& film…

  1. As I write this, there are more people enraged about people being enraged about Arduino use than there are people who are actually enraged about Arduino use. Nobody’s said they’re mad that one was used, but two have stated their ire at those who are mad. Interesting. Regardless, that title pic is really cool.

  2. OMG – there we go. Did you read the blog? This is a true hack, and the Arduino was perfect for it. The line that he “did not even bother to fire up Eagle”, the hand-drawn circuit diagram on graph paper, and the “hey this is an Arduino Blog” comment kind of give the impression that he might happen to know about more than one tool. And if the clever logic behind how the flash controller interface isn’t enough to move it into hack-land, then can’t he at least get some redeeming points for all that duct tape on the stick?

    1. If this is not enough of a hack here, then read this: Hackaday did not publish this because so far no one seems to get ***how much*** better this is than any other open library out there. Read here for my initial analysis on the performance. The current state so far is that some OS libraries use my exponential filter (which is only intended as a benchmark). The “real thing” outperforms this by several orders of magnitude.
      Hackish enough?

      1. Whats my favorite part of this article you ask????

        At the bottom of the page, someone left the comment…

        “You have a brave model, she is smiling even though she knows she is getting soaked!”

        to which the response as…

        “Yes, this is why she is one of Sebastian’s favourite models. She can keep her eyes open even under worse conditions: she is “blue”.”

        Silly… Yes. Funny… Definitely.

    1. Yes of course you can. But the limiting factor was lead time to get everything up and running. I doubt that anyone can setup ad hoc a 555 circuit faster than to coble together some short piece of code. The point is that this approach is trading developer time for circuit complexity. IMHO this is the proper approach for prototypes. 555 or single transistor solutions are for people with significant cost pressure.

      So unless you are going for mass production I doubt that the 555 and single transistor theories are as superior as claimed.

      1. Puh-leeeeeze. With a solderless breadboard, an LM393 and a few R’s and C’s I can build a working circuit in less time than it takes to fire up a text editor and write a single loop. And with real-time delay control (i.e., a small pot) to boot.

  3. [Udo]’s post appears to be the latest of many on an entire site devoted to promoting a single product: an Arduino shield comprising 20 LEDs on a PCB that sells for 23,99EUR as the “Blinkenlight”, and packaged with an Arduino (or clone?) as the “Blinkenlighty” for 49,95EUR.

    From the post:

    “Triggering flashes for high speed pictures is well known to the Arduino community. There exist lots of successful attempts and even some commercial setups. However for a one time set we wanted something that is as cheap as possible and as fast to setup as possible. Thus a Blinkenlighty was used.”

    From the sketch and the diagram, the Blinkenlight shield doesn’t seem to come into play at all: the signals appear to connect straight through the shield to the pins of the Arduino. It’s not clear how the Blinkenlighty is faster or cheaper than a bare Arduino for this purpose.

    I think the Arduino haters aren’t posting because their heads exploded.

    The pictures, however, are fantastic.

  4. Screw the arduino, triggering the flash using the water in the water balloon is genius, so simple, so effective, sure it could be done without the arduino but the two pins is the clever bit, makes you think “why didn’t I think of that!?”

    1. I always think, water in one place and anything that uses electricity in another place. Never the two shall meet. The two are so separate in my mind, that the idea would never occur to me. But i do agree that it is a slick trigger.

  5. People who would be interested, there is an Open Source Project called triggertrap, which has a lot more triggering options. Maybe that justifies using a Arduino because it adds more methods of triggering.

  6. I don’t understand all the hate for Arduino’s on this site… Its a tool that gets the job done… who cares if its a little over powered or you could have used something else.. the point is they made this work with what this person knew… I really think all the Arduino trolls just are jealous and can’t code and Arduino to save their lives…

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