Engineering 181

Kodak Single-use Camera Disassembly

 

Introduction

 

It’s possible to completely disassemble and re-assemble the camera if one uses a little care in taking it apart. The camera is held together with “snap fits”, which are molded into the components. In order to take the camera apart without breaking it, you’ll need to pry the snap fits apart, one at a time. This will require you to use a small tool, such as a bent paper clip or a very small screwdriver, and some patience!  Follow the instructions provided below…

 

Nand pay special attention to the safety guidelines! N

 

Procedure

 

ü                  First, peel the labeling off of the camera, so that you can see all of the snap fits.

 

ü                  Next, remove the back plate of the camera.  There is a set of snap fits on either side of the camera, and one each on the top and bottom as well.  Another small snap fit is located at the top right center of the back plate near the viewfinder and the thumbwheel (see Figure 1).  Loosen these and then gently pry the back off at the upper right and lower left corners, leaving the front cover in place.

 

Figure 1

N         Remove the battery!  This is very important to avoid accidental shock.  The battery is located on the far left of the rear of the camera. Pay special attention to the orientation of the battery before you remove it. In Lab #4, you’ll put the battery back in the circuit board, so it’s important to note the polarity before you remove it.

 

ü                  Once the battery is removed, take out the empty spool in the left film cavity.

 

?          Note the groove that is molded into the camera body and surrounds the area where the film is exposed when the shutter opens. What do you think the purpose of this groove is?

 

 

ü                  At the back of the camera, just above the exposure chamber, you’ll see a small toothed wheel that is attached to a part of the shutter mechanism (see Figure 2). This cogwheel engages the film when the camera is loaded.  As the user advances the film between shots (using the large thumbwheel on the right), the small wheel rotates the cam to which it’s attached, which causes several other actions to occur.  Our next goal is to analyze how this shutter mechanism operates.  But first, we must take care of the capacitor.

 

 

Figure 2

 

NN     The capacitor is the only part of the camera that can bite you.  When fully charged, shorting the capacitor leads will discharge about 300 volts.  Accidentally shorting those leads with your fingers will definitely get your attention!  So, in order to perform the rest of the lab safely, we must discharge the capacitor completely, as described below.

 

ü                  First, use your thumb to rotate the cogwheel to the right one complete revolution.  After you have rotated the wheel as far as it will go, press the shutter trigger (it’s part of the top piece).  This will trigger the flash and dissipate a large portion of the capacitor energy —provided the battery is already removed.

 

ü                  Now, remove the front cover.  Hold the camera near the center of the film cavities and gently pry the front cover off at the sides, as shown in Figure 3.

 

 

 

Figure 3

 

 

ü                  Removing the front cover exposes the circuit board, as shown in Figure 4.  The capacitor is the cylinder located next to the circuit board, just beneath the shutter and lens.  Do not touch any metal parts, especially the two leads coming from the capacitor! Give the camera to your TA so that he or she can completely discharge the capacitor.

 

ü                  This camera is designed to automatically recharge the capacitor after each shot, but with the battery removed, that can’t happen. Once the capacitor has been fully discharged, there is no further danger of being shocked. In Lab #4, you will learn how the Kodak engineers can get such high voltage out of a somewhat puny 1.5 V battery.

 

ü                  Now let’s analyze what’s happening with the shutter mechanism.  Again, rotate the cogwheel and press the shutter trigger.  Watch how the shutter operates. 

 

?          Rotating the cogwheel and the cam to which it’s attached causes at least three other actions to occur – what are they?

 

ü                  Pry off the clear plastic piece that forms the front and rear lenses of the viewfinder.  Then remove the larger gray plastic piece next to it that forms the shutter trigger.  Note that this piece also holds several other pieces in place – be careful to keep the camera right side up during this step, or you may lose several parts!

 

ü                  Make sketches as you go, so you’ll be able to reassemble the camera later. Another hint: if you’re working with  others in your group, keep at least one camera assembled, to use as a guide for reassembly.

 

Figure 4

 

 

ü                  Once the top section is removed, take off the white numbered cogwheel and the gray thumbwheel directly underneath.   You might want to make a sketch of how the pieces fit together.  You may also want to replace the grey shutter trigger without the two wheels, to get a better idea of how the shutter functions.  However you choose to do it, be sure to make careful sketches at each step.  Keep in mind, no detail on this camera is unimportant!

 

ü                  Once you’ve figured out how the shutter mechanism works, turn the camera onto its back, and remove the brass clip wedged into the camera body below the lens.  Loosen the snap fit on the left side of the lens (see Figure 5) and pry off the lens assembly, exposing the shutter.

 

?          What is the purpose of the brass clip?  What other parts does it interact with, and what function do they perform?

 

 

 

Figure 5

 

 

ü                  Now, carefully remove the tiny spring that operates the shutter.  Again, be sure to make sketches of how the parts fit together, and be very careful not to lose any small parts!  Remove the shutter and pop off the circuit board.

 

?          Why is the spring attached to the circuit board, and not the plastic case?

 

ü                  If the lens has not yet fallen out of its assembly, you can remove it by rotating the lens holder that surrounds it counterclockwise. Note that the lens is made of clear plastic —polycarbonate, actually—the same material used to make your eyeglasses, if you’re wearing any.

 

ü                  The camera is now completely disassembled – good work!  Before putting it all back together, take a minute to look at the complexity of the camera body.  Every detail you see on the body, the covers, and the components has a role to play in the design. See if you can figure out why each piece is designed as it is.

 

ü                  Now, try to put the camera back together so that it works!

 

 

Prepared by L. Bisconti and B. Lilly, 9/98