Any old photographers around?
Apr. 29th, 2005 03:20 pm![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
ffuturesToday 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?
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?
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Not helpful again...
Date: 2005-04-29 07:45 am (UTC)My dad has probably still loads (most likely Perutz, not Agfa, should look the same, though) but he's in the wrong country...
Re: Not helpful again...
Date: 2005-04-29 08:02 am (UTC)It's just the usual lack of money spurring me on to feats of inventiveness.
Re: Not helpful again...
Date: 2005-04-29 08:10 am (UTC)Re: Not helpful again...
Date: 2005-04-30 02:55 pm (UTC)Building a laser useful for optics experiments out of junk is more McGyver's style though.
Re: Not helpful again...
Date: 2005-04-30 11:52 pm (UTC)