Time for a makeover of the old PSH with a simple efficient SE requiring no
special parts. Attached is the schematic for the 1DOF Solar Power Smart
Head.

The SE circuit uses just 2 transistors and 4 resistors. It has been
optimized for a 3V solar cell and can only be used for HC logic enable. The
SE circuit needs only 3-5uA supply current which is very respectable
compared to other SEs. The PSH is the standard version 1 1DOF design with
four inverters used to drive the motor. One spare inverter has it's input
grounded to minimize supply current.

Note the special mix of enabled and alway active inverters which are so
arranged to ensure that all inputs have a DC path to +V or 0V when the
circuit is disabled. This avoids high supply current associated with
floating inputs during charging. Even if a HC240 gate is tristate disabled,
the supply current will rise to many milliamps when the input voltage is
near +V/2.

A layout drawing for this circuit will follow.

enjoy

wilf

-----Original Message-----
From: Wilf Rigter
To: 'Will LeGros '; 'beam@yahoogroups.com '
Sent: 3/24/02 1:43 AM
Subject: RE: [beam] Best/Most Recent PSH schematic


Here is a new layout drawing of a much improved Solar Power Smart Head.
It
uses a transistor only SE which is almost as good as a 1381 type and can
be
used in low light conditions. The trigger voltage is 3V and the reset
voltage is 1.9V The 74HC/AC240 chip is wired for two PSH circuits for a
head
with 2 degrees of freedom. If only 1DOF is required then the unused
inverters can be wired in parallel for use with less efficient motors.
Note
the optical bridge is switched off during charging to reduce standby
current.

wilf

-----Original Message-----
From: Will LeGros
To: beam@yahoogroups.com
Sent: 3/23/02 6:21 PM
Subject: RE: [beam] Best/Most Recent PSH schematic

Just a quick question. It appears the 74hc240's pins are facing down
and the 1381's pins are pointing up. Is that correct?


Wilf Rigter <wilf.rigter@...> wrote:



http://bicoreeos.solarbotics.net/psh.html
<http://bicoreeos.solarbotics.net/psh.html> describes the details of
that
version. It is PSH version1 (first and still the best) with the SE
grafted
on by Darrell Johnson.

Wilf

-----Original Message-----
From: xycon_3
To: beam@yahoogroups.com
Sent: 3/22/02 6:12 PM
Subject: [beam] Best/Most Recent PSH schematic

Hey everyone. I was wondering what is the best PSH version for a
solar head like this one:
http://www.geocities.com/SoHo/Exhibit/8281/solar_head.html
<http://www.geocities.com/SoHo/Exhibit/8281/solar_head.html>
I have a bunch of PSH circuits/layouts, but I'm not sure if I have
have the best one. I will be using a BG-micro motor and a 2433 solar
cell, just like this one, but I will be using photodiodes. Jim
doesn't say which circuit he used. Thanks a lot!

-xycon



To unsubscribe from this group, send an email to:
beam-unsubscribe@egroups.com



Your use of Yahoo! Groups is subject to
http://docs.yahoo.com/info/terms/ <http://docs.yahoo.com/info/terms/>



To unsubscribe from this group, send an email to:
beam-unsubscribe@egroups.com



Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service
<http://docs.yahoo.com/info/terms/> .




Will LeGros

URL: http://willber-force.solarbotics.net/
<http://willber-force.solarbotics.net/>




_____

File your taxes online! <http://ca.taxes.yahoo.com> Yahoo! Canada Tax
Centre


Yahoo! Groups Sponsor

ADVERTISEMENT

<http://rd.yahoo.com/M=215002.1818248.3328688.1261774/D=egroupweb/S=1705
948923:HM/A=847665/R=0/*http://ads.x10.com/?bHlhaG9vbW9uc3RlcjcuZGF0=101
6936483%3eM=215002.1818248.3328688.1261774/D=egroupweb/S=1705948923:HM/A
=847665/R=1>

<http://us.adserver.yahoo.com/l?M=215002.1818248.3328688.1261774/D=egrou
pmail/S=1705948923:HM/A=847665/rand=727016552>

To unsubscribe from this group, send an email to:
beam-unsubscribe@egroups.com



Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service
<http://docs.yahoo.com/info/terms/> .



To unsubscribe from this group, send an email to:
beam-unsubscribe@egroups.com



Your use of Yahoo! Groups is subject to
http://docs.yahoo.com/info/terms/

<<SPSH.gif>>