May 13th, 2005

marcus 2013

Production line

Well, it took me three days but I've now built 14 lasers. Should have been 15 plus the prototype, but two of the laser pointers I bought died while I was setting them up - don't know what exactly happened, but basically they stopped lasing and started acting like normal red diodes with a lot less intensity, and nothing I tried would make them start working again. Like an idiot I didn't buy any spares, and the one I have at home is too bright for school use, so now I'll have to see if I can pick one up in Portobello Road or something. Someone visiting from another school saw my production line on Wednesday and said that he could probably find enough lasers in the confiscated property box at his school to build a class set, sometimes there are disadvantages to working at a school where the kids are well-behaved.

I was going to take photos, but they're actually quite boring; just black boxes with a hole at the front, a knob to move a bit of glass rod in front of the laser (to spread the beam vertically), and a switch at the back. Stick on laser warning signs and you have a reasonable facsimile of a laboratory laser that can also be used as a single-slit light box for about three pounds (if you ignore the cost of my labour). Even including it they're still a damned sight cheaper than purpose-built laboratory lasers, the cheapest I could find (which are more or less the same as the ones I just built but commercially made) cost eighty pounds apiece and don't do the ray box trick.

Incidentally, I thought that we'd come up with a new idea with the ray box thing, but it turns out that laser ray boxes (usually with five lasers) have been around for a while. They're ludicrously expensive, of course, but the fact that they exist will be half the battle if anyone says that we shouldn't be building such "dangerous" equipment. I may eventually try to build a five laser (or more likely three laser) box for teacher use, if I can get the beams parallel; they look pretty useful for demonstrations, and I ought to be able to knock them out for a pound a laser plus maybe 2-3 pounds for other components.

Next I must try to find some cheap diffraction gratings etc. to go with them...