Re: The joy of FORTRAN

On 3/11/25 4:36 PM, rbowman wrote:

On Tue, 11 Mar 2025 05:22:51 -0400, c186282 wrote:
 

    The idea of the PV is that it creates its OWN power.
    Anything else, CdS or whatever, requires constant power to work.

 Sort of related:
 https://smfr.org/robots/
 https://www.instructables.com/Tiny-Solar-Powered-Light-Seeking-BEAM-Bot-
Mini-Pho/
 Most of the links in the first page are 404.  You might find something at
 https://www.solarbotics.com/product-category/equipment/power-supplies/
solar-cells

   OK site ... however what I was referring to were made
   as SENSORS, not power-production. Had a few when I was
   young, got 'em from a surplus store. 1/4-20? threaded
   tube body with a clear window at the end. Looking into
   the window there were a collection of TEENY-WEENIE
   silicon blue PV chips, maybe 10 or 12, barely more
   than specks. With a FET high-impedance meter you could
   see they'd generate about 0-5v in bright sun. Likely
   about a milliamp. Never saw much use for them, except
   as a curiosity, until now.
   I *think* they were made for NASA, custom order maybe.
   They likely paid $1000 each for 'em ... I bought 'em
   for like 50 cents  :-)
   A more modern take would be a rolled-up flexible PV
   sheet inside instead of discrete silicon. Pour in
   epoxy and you've got yer sensor, maybe slightly
   more milliamps. Sheet something like :
   https://www.mldevices.co.uk/high-efficiency-flexible-solar-sheets/
   but with smaller individual cells.
   Anyway, looks like I'm NOT gonna find 'em anymore.
   The transmitter, a small amorphous PV hidden under
   the box, getting reflected light. Has awhile to
   charge the super-caps.
   I'll keep thinking about it ... need 200' range and
   no outside power or batts and ultra-low visible profile.
   The box mounts to a piece of 2x6 ... can pull that off
   and route a two or three inch groove in it without
   compromising intended function. That's room for some
   electronics. Do have a zoom camera that can see the
   box, but the chance of actually seeing the mail truck
   stop for 10 seconds .......
   AH ! Solar-powered pocket calculators ! They have a
   very small thin PV strip, can power an LCD calc even
   in room-level light. SOME surplus place has a bunch
   of those !!! More Google fun ! May even have some
   in my old-junk boxes .......