A couple of days ago, I had a Totally Brilliant concept for a cheap(-ish) LIDAR navigation / collision-avoidance gizmo.
Only mildly exotic component is the IR source. Well, no big deal, right? LEDs are getting up into insane power levels these days, so finding one that can put out several Watts in a narrow pulse, at a 10-5-ish duty cycle, oughtta be no big deal.
Oops. Not a lot of high-power IR LEDs out there... and they don't seem to like high peak power... and the rise times seem to run 20-500 ns. Well, that's no good! I was looking for something more in the 1 ns range!
Well, maybe a de-collimated laser. CD/DVD burner lasers ought to have pretty quick rise times, if only I could find the specs for those things that turn up on eBay. Hmmm... and I wonder what the maximum pulse power would be; I think laser diodes tend to fry their mirrors before they melt from excessive current.
When I were a lad, such diode lasers as were to be drooled over in the pages of industrial catalogs were all IR, and were all pulsed, with many-Watt peak output power and minuscule duty-cycle limits. Now... they're all spec'ed as CW.
Well, not all. Hamamatsu, for example, offers a li'l guy with 30W peak output and 2 ns rise time. Hooray! Now, if only I knew a distributor... and of course I have no clue what those critters would cost.
Oh, and in searching for pulsed infrared sources, I found an awful lot of unhelpful things, such as an ultra-fast pulsed IR source consisting of an incandescent emitter and a MEMS modulator... with a 3 ms rise time. Well, that's only too slow for my purposes by about 6 orders of magnitude!
Oh, well. It's not like I'm really going to find the time to develop this thing any time soon. Too much higher-priority stuff. Though, as I discussed with a guy at the Embedded Systems Conference, maybe I need to start publishing the ideas I don't expect to do anything with. Two benefits: (1) maybe somebody else will build it, and I'll be able to buy one, and (2) at least according to the old rules, nobody else can patent it if I publish first (IBM, as I recall, used to have a magazine dedicated to making clever, but not immediately profitable, ideas unpatentable).
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