Alt-BEAM Archive
Message #01068
To: beam@corp.sgi.com
From: "grant mckee" gmbeam@hotmail.com
Date: Sun, 28 Feb 1999 00:30:57 PST
Subject: [alt-beam] Quest for an efficient SE
not sure if this would work but..
here let me organize this a bit
background:
an efficient SE takes a power effecient trigger ie the 1381, a good
solar panel (the best is nasa solar panels that are about 25% efficient
but most of us use solar panels around the 20% mark, anyway I don't
think nasa makes solar panel 1.25in^2) and a power efficient motor (best
Ive seen is about 20 mA) there probably is better just havn't seen them
Idea:
ok the 1381 is probably the most effecient trigger out there right now
so changing thats out, the best way would be to get a very efficient
solar panel but for right now those are out so the change needs to be
with the motor, as of now the pager motor seems to be the motor of
choice; they are fairly efficient but mostly they are choosen because
they are light. There is a problem with pager motor- they are mostly
speed and not much torque, SR's (solar rollers) can be made with a wheel
directly driven by the pager motor but to get the SR moving takes a
large amout of current. To overcome this the pager motor can be geared
down but in doing this there is a loss of power.
solution?
heres my idea use a 555 as a pulse width modulator to the pager motor.
in doing this the pager motor would be slowed down as well as it would
run on less power.
thoughts/ideas?
Grant
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