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The AstroSplash Drop Controller


Colliding drops © James C. Adamson Colliding drops © James C. Adamson


AstroSplash Drop ControllerMany DIYers have asked whether we have a controller to release drops for capturing mid-air drop collisions. Well, now we do, thanks to a collaboration with former astronaut, James C. Adamson, who designed the circuit used by the controller. The latter is available as a kit that you assemble yourself following our illustrated step-by-step instructions. In addition to the controller kit itself, we have available for purchase solenoid valves that we've tested in use with the controller.


Here's what you need to photograph colliding drops. We've divided the list into what we can provide and what you would need to provide.


We provide You provide
  • Drop controller
  • Solenoid valve(s) and fittings
  • Photogate and delay timer for drop detection and flash synchronization
  • Power supplies and cables for the above
  • Water reservoirs
  • Apparatus for positioning the various components
  • Flash units and lighting accessories
  • Camera and lens

In a nutshell, you provide the reservoirs, lighting, and camera, and you set things up how you like. We provide the timing and control system to help you capture reproducible photos without a lot of trial and error. For more detailed information, see our Guide to Setting Up Your Drip Photography System. For information on what is provided in the AstroSplash kit, see the parts list and assembly instructions.


The two main components of the timing and control system are the AstroSplash Drop Controller and the Multi-Trigger 3 or 3+. The drop controller releases a sequence of 1 to 3 drops at intervals from 8 to 120 ms (1 ms = 0.001 s) and also controls the volume of each drop by adjusting the amount of time that the valve is open. All time intervals are adjusted independently, and each is adjusted quickly by the tweak of a knob. Up to 3 valves can be controlled simultaneously, expanding the possibilities for creative effects. In addition, the drop controller opens the camera shutter in readiness for the flash discharge. For the really serious DIYer, there's even a test port to connect an oscilloscope for precise timing calibration.


Multi-Trigger 3+ control boxFlash units are synchronized with the falling drops by using a photogate connected to a timer such as the Multi-Trigger 3+, shown here. If you already have a photogate-delay timer such as the Multi-Trigger 2 or Multi-Trigger 3, that will work fine.


The entire process is controlled with a single push button. Here's the sequence of events that the button push initiates to capture a collision of 2 drops:

  1. The camera shutter opens as a drop is released from the solenoid valve.
  2. The drop passes through the photogate and triggers the delay timer for the flash units.
  3. A second drop is released from the solenoid valve after a preselected time interval.
  4. The delay timer fires the flash after a preselected time interval.

Below are some photos taken with the apparatus. Click on the images to enlarge.


Colliding drops 1 Colliding drops 2
Colliding drops 3 Colliding drops 4


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