- 1 The Five Tabs
- 2 Settings Tab
- 3 The Drops Tab
- 4 Single Sequence Mode
- 5 Loop Mode
- 6 Graph Tab
- 7 About Tab
The Five Tabs
The Drops tab is where you set the drop times and sizes. The drops page also has the controls for the camera trigger and flash triggers.
The Settings tab contains the general settings (things that normally only need doing once), the connection controls, and the valve drain controls.
The Drain tab has controls that allow you to open a valve for draining.
The Graph tab shows a chart of the drop settings. This helps visualize the drop sequence.
The About tab gives basic information about the app version and, after connection is made, the dropController firmware version.
Connecting to the dropController device has already been covered so I will skip the connection process.
Number of Drops
Selects the number of drops to use; from 1 to 9. Clicking the selection button brings up a list allowing you to pick the number of drops. The drop controls on the Drop Data page then become active.
With 2 drops selected the controls for 2 drops are active on the Drops tab
Mirror Lockup is the action of flipping the mirror inside a camera up out of the way. Mirror Lockup may or may not be available on your camera, check the user manual. If you have a mirrorless camera you probably don’t have mirror lock up 😉
On a regular DSLR/SLR there is a small mirror between the lens and the sensor/film that directs the image to the view finder. When the shutter button is pressed the mirror flips up out of the way, the shutter is opened, the photo is taken, the shutter closes, and then the mirror drops back down. The mirror moving up can cause minor vibrations. Mirror lock adds a delay between moving the mirror and opening the shutter. This allows time for the tiny vibrations to stop before the shutter is opened.
Most cameras require 2 shutter button presses for mirror lock up; the first to activate mirror lock up, the second to take the photo. The Mirror Lockup control adds the extra trigger.
When Mirror Lockup is ON, a pre-shutter release signal is sent to the camera. This is the signal to move the mirror. The delay is the time in milliseconds to wait until the shutter trigger signal is sent. 1000ms (1 second) is a good time to wait.
Mirror Lockup must be activated on your camera. If it is not the camera will take the Mirror Lockup signal as a shutter release signal and take a photo.
If you are using a long exposure/open shutter and flash to take the photo then you don’t need to use Mirror Lockup. Just leave it OFF.
Trigger Pulse Times
The trigger Pulse Time is the time the trigger signal is active. It is not the time the trigger is performed.
Times are in milliseconds and 50ms is a good default time. Leave them at 50ms unless you have issues.
Most people will never need to change the trigger pulse times. They were added to a very early version of the dropController to allow me to use an old flash gun that required a fairly long trigger pulse and I simple left them in.
Camera and Flash Triggers
When the trigger is OFF the controls on the Drop tab are greyed out/inactive.
The triggers are covered in more detail in the Drop Data section.
When using the app with a version 2 dropController certain functions and controls are not available. The dropController V2 device is no longer being developed but bugs are still being fixed when required.
The Drops Tab
There are three sections;
– the drop data settings
– the trigger settings
– the START button.
Each drop has several properties:
When using Loop Mode you can increase or decrease the drop start time and the drop size on each iteration of the loop.
Number of Drops
Up to 9 drops can be selected.
Flash Trigger 1
Flash Trigger 2
Flash Trigger 3
The camera and flash triggers can be turned on and off in the Settings page.
The Camera Trigger has 3 modes; OFF, ON + Shutter (Bulb OFF), ON + Bulb
A delta valve can be used to change the camera trigger time when using Loop Mode. Loop Mode and delta values are explained in detail later.
When using Bulb Mode the shutter is opened just before the drop sequence starts and closed just after the sequence finishes. To use Bulb Mode your camera must support bulb mode and be in bulb mode.
Ideally, the camera should be in manual mode or bulb mode when used with the dropController.
There are 3 Flash triggers and each trigger works in the same way.
Each flash trigger can be turned ON or OFF on the Settings page. When OFF no trigger signal is sent to the flash.
When the flash trigger is ON the flash trigger controls are active. When active the flash trigger time (in milliseconds) can be entered. When using Loop Mode a delta value can be used to alter the trigger time on every iteration of the loop. Loop Mode and delta values are explained in detail later.
Normally only one Flash Trigger is used. When using multiple flash guns, the flashes should all be connected to a single trigger. The additional flash triggers are designed to be used to fire flashes at different times, not to fire separate flashes at the same time. For more details about using multiply flashes see Using Multiple Flashes.
The START Button
When connected, clicking the START button tells the app to send the drop data to the dropController device. Depending on which mode you are using, Single Sequence Mode or Loop Mode, different things happen.
In Single Sequence Mode the data is sent immediately to the dropController and the drops are created straight away. In Loop Mode the Loop Page opens and waits for the user to start the sequence.
Single Sequence Mode
The app is in Single Sequence Mode whenever it is not in Loop Mode.
On the dropController device, the yellow LED turns off and the green LED turns on. The green LED shows that a drop sequence is active on the controller.
When the sequence is finished the green LED goes out and the yellow one comes on again.
In Single Sequence Mode delta values are ignored.
Loop Mode is the heart of the dropController and it is Loop Mode that makes getting collisions so easy.
There are two methods used to start the next sequence, either a TIMER or a BUTTON click.
You will need to experiment to see what wait time suits you. I generally use around 10 seconds. This allows time for the water in the tray to settle and also allows time to move any bubbles out of the way.
If you find you are constantly removing bubbles or adjusting things then it is probably better to use the BUTTON option.
When TIMER is selected a timer is used to delay the next drop sequence. When BUTTON is selected, the next sequence is held until the user clicks the small START button.
When using the TIMER option the first drop sequence is started as soon as you click the START button. After the first sequence is completed the timer will start a countdown and when it reaches zero the next sequence will start automatically.
While the timer is counting down, clicking the STOP button pauses the app at the current sequence number. Click START to continue. Clicking RESET resets sequence number back to 1.
Delta values are values that change inside a loop on every iteration of the loop. For the dropController, this is the drop start times, the drop sizes and the trigger times. Any value that has a INC/DEC [+/-] control has a delta value.
The INC/DEC [+/-] button allows you to either add to or subtract the delta value. INC for increase and DEC for decrease.
For example, on every iteration of a loop you can change the drop start time, make the drop smaller or bigger, and move when the flash fires.
– On the first sequence, the drop will start at 100 ms,
– on the second sequence it will start at 110 ms, and
– on the third it will start at 120 ms and so on.
There is no size delta value so the drop size will not change.
Loop Page Labels
|SOL||The solenoid valve being used.|
|START||The drop start time with the delta value in square brackets.|
|SIZE||The drop size with the size delta value in square brackets.|
|STOP||The drop stop time. This is calculated by the app.|
|CT:||Camera Trigger. Set to trigger at 0000. No delta|
|FT1:||Flash Trigger 1. Set to trigger at 2400ms. No delta.|
|FT2:||Flash Trigger 2. OFF|
|FT3:||Flash Trigger 3. OFF|
Delta Values In Use
Let’s see a delta value in use. In the following example I am making the Flash Trigger 1 fire at a slightly later time each loop/iteration.
There is one drop which is on SOL 1; the start time 100, start time delta is 000, size 30ms, size delta 000.
The Camera Trigger is on and set to Bulb Mode.
A single Flash Trigger is active and set to 150ms with a delta value of + 10ms
When the sequence is finished the button changes back.
What does the above do? If you were to run these setting you would capture a falling drop starting from just under the valve.
Delta Value Limits
The times that are changed due to a delta value cannot go outside of their normal range. If the value exceeds these limits it is set to the limit.
For example, the drop start time has a minimum start value of 0 and a maximum of 9999. If a delta value tries to make the start time lower than 0 then it is set to 0. If a delta value tried to take the start time beyond 9999 then the start time is set to 9999.
Drop Data Error Checking
In the current version of the Android app there are no checks on the drop data values. This means it is possible to have overlapping drops on the same valve.
Here the 2 drops use the same valve and have overlapping times. This means it would produce 1 drop sized 70ms.
The is fairly easy to spot when looking at the Drop Data page but hard to find when it is caused by delta vales.
The Graph page shows the drop times and trigger times in chart form. This aids visualizing the drop times and is especially useful for more complex sequences.
Here we have 4 drops and the flash set to fire at 564ms.
The shutter is set to 1/2 second exposure which means the shutter will be open from 400ms to 900ms.