Approach with 2 wedges. The aim was to find a simple mechanism that allows for high precision. If you tighten the screw the lower wedge moves left and pushes up the upper wedge with the camera on top of it. If you loosen the screw the camera moves down. Because of its simplicity it would be less susceptible to errors.
You can download the model here: Media:ModelWedges.zip. You need to have Google SketchUp installed to open the model.
First remove the lens of the camera. Use a screwdriver to unscrew the outer parts. Then use a hand saw or a pair of nippers to crack open the case around the cable. Carefully remove the plastic without damaging the cable. As a result you get the PCB with the cable and the LEDs. For now leave the black plastic ring on the PCB as a protection for the sensor.
The second step is to remove the LEDs. Unsolder them carefully and clean the solder holes with a desoldering pump.
After checking and improving the functionality of the design with the cardboard construction the final model can be built. Here the base material for conductor boards is used. It is made out of epoxy with a copper surface. This makes the material easy to work on. The smooth surface of the copper allows for a smooth movement of the wedges. The design was expanded by two small springs that constantly pull down the camera platform, preventing the platform to be pushed up by the firm cables of the camera. What you need is:
An iPad with 52ppcm (pixel per cm) was used to calculate the camera resolution. This means that one pixel is 10/52 mm wide, that is roughly 0,2 mm. These 0,2 mm equal 300 pixels of the camera image. Therefore one pixel of our camera shows 0,00067 mm (0,2mm/300) of the specimen. Knowing that the image is 640 pixels wide and 480 pixels high, the image size adds up to 0,43 mm in width (0,00067*640) and 0,32 mm in height (0,00067*480).
With the objective of finding interesting material to examine Artemia Salina were breeded. Artemia Salina is a very old species of brine shrimp. Breeding sets can be found in the pet shop and have been a gimmick in childrens science magazines on a regular basis. Unfortunately even the newly hatched shrimps called nauplii are to big to be examined thoroughly with the camera.
Another possibility to create specimen to look at with a microscope is the hay infusion. Collect a handfull of hay and dry leaves and about 500 ml of pond water. Put the hay in a glass bowl and pour the water on it. Keep your hay infusion in a bright place at room temperature. After a few days you can find monads like Paramecium, Amoebia or Euglena.