Method

Trigger and Delay Circuits
The sound trigger and delay circuit work hand in hand. The sound trigger uses a piezo buzzer as a microphone. When a loud enough sound is created such as a golf club colliding with a ball, the amplification circuit provides enough current to latch a SCR (silicon controlled rectifier).

The closed SCR output can either go directly to the flash unit to set it off instantly or it can go to the delay circuit. The delay circuit uses a 556 timer chip and a number of other components to create a delay in seconds equal to the capacitance of the "controlling capacitor" in microfarads.

I used a 103 ceramic capacitor. 103 means a 10 and three 0's. To get microfarads, you divide that by 1,000,000.

10,000 / 1,000,000 = .01uf

So a delay of .01 seconds is created.

Trigger and Delay
Either a photogate or sound trigger would be appropriate for detecting the impact. A photogate may have been a better choice because the club swooshing through the grass tripped the sound trigger prematurely a few times. To get shots later in the flight of the ball, a delay circuit is necessary. Triggers and the delay circuit like mine can be made from schematics at www.hiviz.com.

Camera
The camera chosen must have manual settings so that it doesnt try to focus in the dark. It is also a benefit to have an adjustable aperture for better control of the light entering the camera. To be able to capture the flash on film, the camera must have a maximum shutter speed setting no shorter than a second. Otherwise it would be quite hard to synchronise manualy. Digital cameras will work as long as they have manual focus and shutter speed settings.

	Method
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Basic Idea To find the force on a golf ball, I need a way to find its final velocity and the amount of time it gets accelerated by the club. Using trigger and delay circuitry to photograph the ball at specific times, I should be able to do this.
Trigger and Delay Circuits The sound trigger and delay circuit work hand in hand. The sound trigger uses a piezo buzzer as a microphone. When a loud enough sound is created such as a golf club colliding with a ball, the amplification circuit provides enough current to latch a SCR (silicon controlled rectifier). The closed SCR output can either go directly to the flash unit to set it off instantly or it can go to the delay circuit. The delay circuit uses a 556 timer chip and a number of other components to create a delay in seconds equal to the capacitance of the "controlling capacitor" in microfarads. I used a 103 ceramic capacitor. 103 means a 10 and three 0's. To get microfarads, you divide that by 1,000,000. 10,000 / 1,000,000 = .01uf So a delay of .01 seconds is created.			Photographic Equipment Needed: Flash A commercial flash unit like the Vivitar 283 can be used. The flash must have an automatic setting so that the duration can be decreased. It is preferable for it to have a removable light sensor, known as an "Auto Thyristor." It allows the two rightmost connections to be shorted out, giving the default shortest duration. Either a hot shoe adapter or PC cable is needed to be able to connect the trigger to the flash. Here is the setup I used for some of the non-golf pics. In the upper left you see the flash and trigger circuit and the wire that stretches off to the right has the mic on the end of it.
Displacement To figure out the displacement of the ball after the 1/100 second delay, it is necessary to have some sort of scale. For this, I will take a picture of a yard stick positioned with the beginning in the middle of the ball on the tee. The experiment photos will be taken without moving the camera at all, so that the position of the ball relative to the yardstick will be accurate. Obviously it would be impossible to hit the ball with the yardstick in the way, so later in a photo editing program I will superimpose a cropped image of the yard stick to show the distance the ball traveled. Time Accelerated Determining acceleration time requires experimentation with the delay circuit to catch at least two images, the first instant that the ball isnt in contact with the club and the one right before that where it is. Some closeup pictures should reveal that the ball squishes upon impact. Adding time to the delay in small incriments will finally reveal a picture where the ball is no longer in compression and is separated from the club face.			Trigger and Delay Either a photogate or sound trigger would be appropriate for detecting the impact. A photogate may have been a better choice because the club swooshing through the grass tripped the sound trigger prematurely a few times. To get shots later in the flight of the ball, a delay circuit is necessary. Triggers and the delay circuit like mine can be made from schematics at www.hiviz.com.
			Camera The camera chosen must have manual settings so that it doesnt try to focus in the dark. It is also a benefit to have an adjustable aperture for better control of the light entering the camera. To be able to capture the flash on film, the camera must have a maximum shutter speed setting no shorter than a second. Otherwise it would be quite hard to synchronise manualy. Digital cameras will work as long as they have manual focus and shutter speed settings.