Alt-BEAM Archive
Message #03179
To: sbolt@xs4all.nl, beam@corp.sgi.com
From: Bumper314@aol.com
Date: Tue, 11 May 1999 02:32:46 EDT
Subject: [alt-beam] Re: SMD SE
In a message dated 5/10/99 11:18:35 PM Pacific Daylight Time, sbolt@xs4all.nl
writes:
>If you trigger at for instance 2.5V, and your driver is any good,
>you'll be wasting an initial 150mA through that resistor!
I thought the pulse looked a little dead =), so what should i do then. I cant
swap out the SE now, its in the middles, I can get to it though. Should I put
a resistor in series with the solar cell?
> SunEater_V fits easily on 2.7x3.5cm. Very enthousiastic,
> tinyPager-motored `bot.
> But if you have easy access to a nice choice of 1381s, why not use
> them. 1381 output connects to the active high input of a monostable
> (1/2 74HC221, for instance). A 100N cap and a resistor - somewhat
> less than 1M for best pulse, I imagine - determine the output
> timing. 1K connects a BC817-25 to the active high output. The
> transistor drives your coil and there you probably are. The
> smallest supercap (47000uF) would provide sufficient current in a
> light and compact package, and the voltage would hardly drop
> between pulses.
>
> That's five and a half components for a single SE, or eleven for a
> double version. The 74HC221, all resistors, the 100N cap and the
> driver are SMT. Your 1381 will seem rather large...
>
wow, is stuff up on your SunEater_V yet? I dont think i followed your
description to well on that SE, would you mind wipping up a schematic? And
about my 1381, I guess I didnt write that well, I actually made another one
tonight and its only 5mm by 5mm by 2mm. not bad.
STeve
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