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Building the first prototype
So far it is clear what we want to build. Now lets gather the parts.

It come to my attention that maxell CD-r have the dummy CD already frosted from one side - creating nice uniform ground glass.	This was lying in my basement for ages. Even if you don't have any CD player to salvage yet, ask your friends or buy some for five bucks in a pawn shop.	A good helper is always a welcome addition and much more fun. Try to get one who is not constantly stealing parts and screws when you are not looking.
Finally the player will have second chance!	Here is the motor piece that was held to the body by 3 screws.	I took out the laser and lens and this is what I need.
Lens cap from the bottom part of the lens will be used to hold the lens to the board and still to be able to take it off.	Of course I need to create a hole in it so the light can pass through.	I need three boards as designed in previous page each with large hole.

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We have what we need so let's put it all together.

	First step as designed on the previous page is to attach the motor piece to the board. Not much science here, I also reused the rubber silencers.
	Second board is attached with the lens cap and lens in the position. By looking through the lens you already see mirrored image on the ground glass...ehm... the frosted CD.
	I attached the bottom third board that will go to the camera through MACRO lens. (the macro lens is not yet added to the device). I attached the battery and all is ready for first experiments.

The goal is to find the distances so I can use the whole focus range of the lens.

This is determined by the lens distance from ground glass. This should be very carefully set so I can reuse the whole focusing range of lens. Here is a simple way to find the correct distance: Focus the lens to infinity and then point the whole device to far away objects such as far buildings, trees etc. and look from the back side on the ground glass. There is no chance that the image is already in focus. We have to adjust the distance between the lens and ground glass with the screws so the projected image gets in focus. With this we calibrated the device so we know we can focus on infinity.

Since we have zoom in our camera the distance from ground glass to the macro lens is not that sensitive once we make sure we can focus with the camera on the ground glass from that distance. We can always zoom in or out to cover the best area to avoid vignetting. The problem is if you can't focus at all, then you have to move the camera away from ground glass until you can focus. The MACRO lens has the function to shorten this distance.

This took me 2 hours to build in one evening, and it is already dark outside so I can't really set the focus on infinity today.
Let's leave it for tomorrow.