Marcus L. Rowland (ffutures) wrote,
Marcus L. Rowland

Any old photographers around?

Today I took a stab at building a prototype laser for science lessons. Basically, it's the business end of a laser pointer with an external battery pack and switch, mounted inside a box and aligned so that the laser is parallel to the long axis of the box and the plane of polarisation is vertical. They cost silly money if you buy them from laboratory equipment companies, so I'm going to build them from exotic components such as cheapo laser pointers, modelling putty, insulating tape, cardboard, etc. I reckon to knock them out for £2-3 if I can get a good price on components. I want to build 15, to be used as lasers for A-Level physics, and also as ray boxes for general optics. Which is where our problems begin...

For general optics you need a vertical line of light, e.g. a bulb behind a slit, not a thin beam. The way you get around this with a laser is to put a cylindrical lens horizontally in the path of the beam, so that it spreads vertically. In practice, the easy way to do this is to fix a bit of glass rod in front of the laser. Trouble is that it needs to be removable, since the A-Level lessons need an unmodified beam.

Step forward the two-part Agfacolor slide box, about 110 x 55 x 55mm, as sent out in their millions by Agfa in the seventies and eighties. They're strong rigid plastic, with a translucent lid, and at one end, on the outside, is a little niche designed to hold a label. I used one for the prototype, and it's exactly the right size and almost perfect for our needs. The label holder is just the right size to hold a little metal plate with a bit of glass glued to it, and there's enough free space inside for any additional electronics we might want to add at a later date.

Can I find anyone selling a similar component box? No. Which is where I hope people may be able to help. I've got three, I could do with at least 12 more. Anyone got any they don't want?

  • Another Jab

    Had my second Covid jab today. Feeling fine so far, we'll see how it goes. Hoping I'll be well enough to get out and vote in the local government…

  • GURPS Lensman article

    I forgot to mention that one of my old articles for Pyramid magazine is on line on Steve Jackson Games' web site - Holy Klono!, a discussion of a…

  • Another RPG bundle offer - Legendary Planet

    Another one I'm not familiar with - Legendary Planet, a multi-world fantasy/SF setting for D&D 5th edition and Pathfinder rules:…

  • Post a new comment


    Anonymous comments are disabled in this journal

    default userpic

    Your reply will be screened