Dropsduino stems from my interest in photographing water droplets, already possessing Photoduino I experimented until I felt the need to expand and drop controls.

With this Hardware complete firmware are able to simultaneously manage 3 solenoid 12 Volt, set whether to use the shot of the camera or the flash to catch the picture and finally the trip delay from the moment in which it closes the last valve

Dropsduino has no sensor, because you just set the shutter lag since the last straw.
The shooting mode as that they are two:
1) Light Mode - The shooting will be done in bright light without the need of a flash in this mode, the shutter opening delal camera that captures the photo.
2) Flash Mode - The shooting will be done in a dark room without light, recommended two external flashes (1 is necessary), in this case the camera's shutter is open before starting the drops, and the delay set by the last drop the impress the flash sensor to capture the photo.

Wiring Diagram - Current Firmware

The management of the valves is divided into:
1) Drop Time in ms
2) Range Drop in ms
3) On or Off for the second and / or third valve

All these parameters from light to delay the valves can be operated with the buttons and the built dysplay. Currently the Back button is not implemented yet, it is necessary to go back to the confirmation of setting a voice so head back to the top menu once you find the right combination, you can always memorizarla to share with those values.
For reasons of space I have separated the three relays that activate the valves by the control circuit, but if you have a larger box you can put everything together. The v0.4 firmware currently has bugs, but hopefully with time to correct and expand the functions
Known bugs:
- ESC button does not work (firmware problem)

Upcoming developments in v0.5:
- Creation of 5 or more save slots settings
- Multilingual Settings (EN-IT)

List components:
- 4 small buttons (2 red, 2 blacks)
- 3 medium buttons (3 blacks for bypass valves)
- 3 jacks 3,5mm
- 3 connectors 3,5mm
- 2 4N35
- 2 MOC3022
- 1 potentiometer 10K
- 4 resistors 10K
- 4 resistors 200ohm
- 3 relay 5V
- 1 LCD 16x2
- 1 punch card
- 1 Arduino Board 2009 o UNO
- 3 solenoid 12V
Some of my photos taken with Dropsduino