Design. Deploy. Do.

Somewhere, I forget exactly where, I came across a design strategy which in essence promotes the following cyclic process : Design >> Deploy >> Do, and then back to the “Design” stage to rethink the concept based upon your experiences from the “Do” stage.

 

This doesn’t necessarily mean that everything you tackle needs to be endlessly redesigned and redeployed. If you are satisfied with the experience of the “Do” phase, then no further work or effort is required. If however you discover gaps or inconsistencies, then revisit Design. Deploy. Do.

 

I embarked upon a Liquid Sculpture project recently which had an overly complex electronics component. I intended publishing  the project and whilst it was acceptable for my purposes, it would not have been the case for many people wishing to build the project for themselves.

 

 

The schematic above forms the “engine” for liquid sculpture images and was pretty linear and simply, or so I thought. Reading from left to right; the input voltage is 12 V and undergoes some regulation to eradicate any ripples in the power. This drives a function generator (a.k.a. signal or tone generator) which is capable of generating a constant tone in the 10 – 10,000 Hertz frequency range. For liquid sculptures a tone in the vicinity of 80 Hz is ideal. A tone of 10,000 Hz is just an ear-piercing siren-like noise and would appear to be useless for my purposes. The generated tone could either take the form of a sine wave, square wave or sawtooth wave. Where the sine wave tone is acoustically consistent and the other two waves are just plain noisy. The tone frequency (Freq) is governed by a potentiometer (like a volume control) and there was no real way of knowing the exact frequency being generated and it boils down to the tone sounding correct or not. The tone output goes through a pre-amplification stage to bump it up in intensity using another potentiometer (Power) which provides the input into a pure power amplifier. The output from the amplifier block drives a 65 Watt 4 Ohm audio speaker (round shape with a diameter of 120 mm)

 

I created a breadboard prototype and the cost of components was not excessive and would have ultimately required a circuit diagram for a stripboard or a custom PCB. As electronics is not my forté (I develop Business Intelligence solutions) and although I can get myself around most basic electronics, I would not be comfortable providing a circuit that could in theory cause problems or failure for anyone who tackled the project.

 

The prototype from my initial design was used to take this image.

 

 

There were a few problems with this design. Triggering the camera and strobes had to occur simultaneously with the generation of the tone. It was hard to recreate a specific tone if the “Freq” potentiometer was adjusted or if you set up the gear again after a few days.

 

Considering “Design. Deploy. Do” I realised that my approach needed to be simplified.

 

I decided to do the following; Forget about generating a tone using a function generator, and create MP3 files for the selection of tones I required. This made the entire process a lot simpler. Now I can burn the audio copy of the MP3 files to a CD. I can reserve the Left channel for a countdown leader (three beeps spaced one second apart, or even a verbal “3, 2, 1, Go!” sequence) and reserve the Right channel for the frequency burst to drive the liquid sculptures. The schematic below shows the simplification where the audio source (CD, MP3 or computer) drives the power amplification and the stereo output channels. This way I can recreate the sound sequences repeatedly and weeks apart at that.

 

I have also decided to upload the MP3 files for anyone to use (find them in the store link in the next few days)

 

 

Here is sample of the liquid sculptures using the MP3 method – Not that the result  would be any different, it just makes the manual timing for triggering the shutter or strobes so much more easier – more about this in a moment.

 

Some helpful suggestions:

 

1. It is possible to shoot high speed with an external strobe in ETTL or ITTL mode (right up to 1/8000th of a second in some cases).

 

2. But as all the action takes place in the first few 10th’s of a second, it might be beneficial to engage mirror lockup so there is less to do at the point of taking the shot.

 

3. Work in Manual Mode. Manual Focus is required so that the camera doesn’t move from the focus point that you chose and similarly for aperture, white balance and ISO. This is less for the camera to do and goes a long way to helping you catch the action.

 

4. Shallow depth of field occurs at the large end of the aperture range so choose smaller apertures (F16 perhaps).

 

5. Consider triggering the strobe in manual mode at 1/128 or 1/64th of a second to shorten the duration of the exposure. A standard strobe fired at 1/64 is equivalent to a shutter speed of approximately  1/32000th of a second – You’ll need to be shooting in the dark for this to work with the shutter wide open.

 

I will be covering this project in more detail in the weeks to come. Ultimately I would like to incorporate an Arduino solution into the project to help trigger and control the devices required.

 

More, later.

 

Click!
Chas.