![]() I'm sure I've omitted some important detail, but I hope its relatively clear. A useful tool for alignment is lining up the main 'reflected' dot that will invariably occur to the centre of the preceding module element. Once all modules are in alignment - you should see some sort of projection - if out of focus, then move the focusing lens back and forth relative to the slide to get the optimum sharpness. This of course means moving the focusing lens too. Adjust the size of the expanded dot by moving the slide holder up and down until you're happy. Set up another 'scaffold' and position the lens so that the beam of the laser passes directly through the centre. As before set the lens within a 'holder' - using the polymorph or other materials. If you want to buy some quality glass lens, then a number of reputable laser shops online can supply these. The basic shape extrudes inwards and expands the beam. You can find these lens in old disposable cameras. You can use 2 lens to expand the dot in a shorter distance, but brightness does suffer a little bit for each filter the laser has to pass through. ![]() Using a concave lens, we expand the beam enough to cover all or most of the 35x24mm area of the slide. I'll leave the method of attaching laser to you, but remember you may need to reposition it slightly later, so gluing it down now may cause regret. Once you are happy with the alignment, mark the position with a pencil. Ensure the laser is aligned along the line, and is also exactly parallel with the plank/rail. Turn the laser on and use a set square aligned along the centre line. Position the laser (in heat-sink) loosely on the top. Best to create this 'scaffold' before attaching any of the components to the top perspex/pcb. This allows the vertical level to be raised up and down accurately. The bottom piece slots into the mounting block, and the other squarely above it, with bolts in each 4 corners. To mount using the rail, use two 72mm perpex/pcbs'. In this quick and dirty example, I'm merely pressing the laser into the centre groove with a polymorph blob. Find an aluminium heat sink from an old computer, and drill a hole big enough to fit the pointer into. Heat is often the death of lasers! Assuming it'll be on for longer than a few minutes, you may need a form of heat sink to dissipate the heat. Be careful soldering this while - you can easily dislodge other components and destroy the laser module. Since laser pointers often have a press switch, I will pull them apart and bridge a wire across the switch so that when-ever a battery is attached, it will stay on. Mounting the Laser Assuming we using a pen type laser pointer we need to mount the laser into a holder which securely hold the laser in position with no movement at all. They also allow a great degree of modularity - being able to swap different lasers, lens, etc in and out quickly. NOTE: I will use the Dinkle rails for this instruction simply because they make alignment so much easier. Hole making bits for drill (if using wood to create lens holders).perspex or pcb 72mm with for Dinkle mounts. ![]()
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