To create exciting (water)drop photos, I need a setup to control the frequency and timing of the waterdrops falling down and splashing onto eachother. There are some solutions but those are all quite expensive in my opinion. Maybe I think differently about that after my DIY project.

So I decided to build my own waterdrop setup. When I talk about waterdrop I also mean other types of liquid as long as it doesn’t explode.

I’ll update this page during the DIY project which started November 7th with finding a suitable solution. Currently (December 11th 2010) the waterdrop device is ready in it’s initial version.  Pictures made with this setup can be found here and here. Specific information can be found at:

There are some basic parts I need for the waterdrop setup which are:

  • Watertank
  • Electric Valve
  • Main controller
  • some interfaces
  • some installation to mount all.

Because creating a sturdy mount and creating a waterbasin are not the rocket science part of this project, I’ll save them for later on. The main interesting part are the Electric Valve that needs to open and close quickly to create a waterdrop on the moment I want it. Also I need some part to control this valve and control the shutter of the camera and the flash. I need some microcontroller or computer for this. Then to connect everything together I need some interfaces that can handle the current and voltages of the components used.

Controller

My first thought were using a regular parallel port (old centronics printer port) on an old laptop connected to the electric valve, camera and flash to control the setup. Some simple MS-DOS or Linux application written in C++ should do the trick. I’m not completely convinced that the parallelport can handle the resolution I need (0,5 milliseconds). Actually the OS should support realtime processing to prevent the OS from accidently delaying the time intervals.

Because having a laptop near a water setup is not the most ideal situation and I have some experience in programming microcontrollers I looked for a microcontroller setup. A microcontroller is a combination of a microprocessor and necessary controllers for memory and input and output in one single chip. I found the Arduino Uno which is rather cheap (€ 25,-), has a open source programming environment and it also looks like it can handle microsecond resolution besides milliseconds ;-). This means possible more accuracy in the timing of the drops. It has many input and output ports, even enough to connect an LCD display in the future.

The Arduino Uno board arrived within 2 days and programming is relatively easy when you have some experience in a C – alike programming language. The prototype of the setup used a serial (USB) connection to the PC for receiving input like program choice and entering the delays. Later on I’ve replaced the serial communication with an LCD display and keypad so the device can be used without a PC.

Solenoid Electric Valve

Finding a suitable valve is rather difficult if you don’t know what to look for. The Shako PU220AR01 is used by other people too for creating waterdrops and I can confirm it is a suitable solenoid valve.
The valve will be connected with a hose to a watertank and it will open on an electronic pulse by the microcontroller. The time the valve is open will determine the size of the drop.

I ordered my valve at APEX Industrial Supply in the US. Make sure you get the right voltage (They have 110 volts AC and 24 volts DC of which I recommend the latter because it’s more safe). I received the valve within 3 business days (from US to the Netherlands).

You also need some brass hose pipes together with the valve. I recommend reading this page and start searching. Productnumbers can be found on that page too.

 

Sound Interface

To spend some time programming and experimenting a little more without the solenoid valve, I decided to build a sound interface to trigger the camera shutter after a large sound is detected. During the last days I’ve found more sites where the Arduino is used for high speed photography purposes. I will program mine myself, but the information on specific interfaces or sensors is very useful. I found this PDF with a sound detection circuit. It does work with contact noise (put the microphone on the table and drop something on the table). Popping a balloon does work too but I’m not to happy with it yet.

The sound interface can be connected to the Arduino Uno.

Remote Shutter Cable

To trigger the shutter of the camera you need a wired connection to the camera. I found a wired remote shutter trigger for $ 3,50 in HongKong with free shipping. I don’t care about the quality of the switches, I just need to cut off the cable + Connector. The cables are of sufficient quality. I smashed the switch so I could look inside to determine the wiring and the way the switch works.

Wire A will connect to Wire B when button is pushed half way (Auto Focus). Pushing the button further (trigger Shutter) also connects Wire C.

Autofocus = Wire A + Wire B

Shutter = Wire A + Wire B + Wire C

Again, look into the switch to see which wires you have to connect to trigger the autofocus and/or shutter.

Interfacing with Flash and Shutter

I use 3 optocouplers each connected to a digital out pin on the Arduino to trigger the flash, autofocus and shutter. I used the 4N25.

Watertank

You should make a Mariotte Siphon which provides a stable pressure to the valve. I used a regular PVC drain pipe of 5 cm diameter. You can buy standard caps to close such pipes and glue them together. I also found a screwmount cap for this drain pipe, which is very useful when you have to empty the tank. You should be able to find some hosepipes in a petstore (aquarium stuff) so you can mount the hoses onto the pipe etc.

 

Costs & alternatives

When I started to write the article, I had only found pre-build systems for about 200 – 400 USD. When you have enough electronics and programming knowledge, you should be able to build a microcontroller controlled system yourself from scratch for half that price. The basic parts are cheap, but it becomes more expensive if you want to put it in a nice case, put an LCD display and Keypad on it. Although a 20×4 LCD and 16 key keypad can be bought on ebay for about 15 dollar. All the little ones add up quickly.

An alternative is the Camera Axe Store where you can buy an assembled or DIY Kit of the Camera Axe. It will save you a lot of time designing and developing the hard- and software.

I’m happy to help with questions, but please first use Google before asking 😉