Alt-BEAM Archive

Message #07568



To: beam@sgiblab.sgi.com
From: Evan Dudzik evandude@yahoo.com
Date: Thu, 11 Nov 1999 11:24:52 -0800 (PST)
Subject: [alt-beam] has the patent expired?



has tilden's patent expired? I would like to sell
some carbots to people i know, but I have to worry
about the patent... and I asked him, but he did not reply.

=====
+------------------------+
|http://surf.to/photovore|
|Photovores online! |
|Evandude Dudzik |
+------------------------+
__________________________________________________
Do You Yahoo!?
Bid and sell for free at http://auctions.yahoo.com



7569 Thu, 11 Nov 1999 11:45:13 -0800 [alt-beam] Re: It's ALIVE....Good News From The PSH Group "'beam@sgiblab.sgi.com'" Wilf Rigter For those who can't find 5M pots and are using LDRs or efficient PDs,
generally are about 5K-100K in medium light, you can use 1M pots for R1-2.
If necessary, you can also use 0.1uf caps for C1-2

Here is a tip to help with tuning a breadboard version of the powersmart
head of figure 2 of the tutorial with a small gear motor or equal requiring
about 20 ma to turn. For these adjustments, the head is effectively upside
down, the LDRs don't move and the motor shaft rotates. Use a 3 to 6V battery
(depending on minimum required for motor) and measure the supply current
with a multimeter or temporarily install a LED in series with the batteries
and the circuit. If you use the LED method, you may have to add an extra
battery to pump up the voltage by 1.5V to compensate for the voltage drop
across the LED.

1. Expose LDRs to roughly equal light and turn R1 midway and turn R2 end to
end.
2. Note the current or LED brightness is highest at one end and lowest at
the other end.
3. Leave the R2 set at the end with the highest current/brightness which is
R2=0 ohms
4. Now turn R1 end to end, and observe the current/LED brightness
5. Leave R1 set at the lowest current/brightness end which is the maximum
resistance across inverter A
6. Now play with shielding the LDRs with your hand or shining a light from
one to the other.
7. Note the motor responds quickly to the light changes: turning left or
right. Note which LDR causes left and right rotation.
8. Carefully try to balance the light on both LDRs and notice when the motor
stops, the current/LED brightness increases!
9. This is the least efficient setting of the PS head which also correspond
to the equivalent power required for a bicore head.
10. Adjust R1 a touch (5%) away from the previous maximum setting.
11. Now play with shielding the LDRs or shining a light from one to the
other.
12. Notice the LDRs are slightly less sensitive and the range over which the
motor slows down and then stops is wider now.
13. With LDRs roughly balanced, adjust R2 just until you see a sudden drop
in the current/brightness.
14. The power-saving mode which reduces total current to about 2ma when the
light is balanced on the LDRs.
14. Now play with LDRs and notice reduced current/brightness as the motor
slows down near the balance point.
15. Adjust R2 to give the smallest possible setting where power saving
occurs. This gives the highest sensitivity.
16. Try different light level and make small adjustments to R1 and R2 to
maximize the range of light over which it works.
17. Now that you have proven the circuit works mount components on a
perfboard and bench test again.
18. Do some final tuning by aligning LDR stereoscopic angle and using black
tubes for "aiming" and matching sensitivity.
19. Turn head right side up and be prepared to do more tuning using the same
method.
20. Note the minimum supply voltage needed for reliable motor operation and
prepare suitable solar power source and SE trigger circuit.

I found the minimum voltage for most small gear motors I have is about 4.5V
which means using the Chloroplast or 1381U SE.

hope this helps.

Wilf Rigter mailto:wilf.rigter@powertech.bc.ca
tel: (604)590-7493
fax: (604)590-3411

> -----Original Message-----
> From: Elmo [SMTP:andrewe@ilid.com.au]
> Sent: Wednesday, November 10, 1999 11:58 PM
> To: Beam Mailing List
> Subject: It's ALIVE....Good News From The PSH Group
>
> Wow!
>
> I am proud to announce that my PSH depression has lifted and that i now
> have a breadboarded version of the New non-solar PSH circuit working!
>
> Its responding to light stimulus well but still seems to have a few bugs
> in it (sometimes it keeps running after acquiring the brightest light
> source). I now have some trim pot playing to do and experimentation with
> various photo diodes and LDRs but it looks like its a go-er.
>
> More news and web site details shortly.
>
> Elmo



7570 Thu, 11 Nov 1999 15:05:10 -0500 [alt-beam] PSH PDF on-line BEAM List Victor Snesarev Thanks to Dave of Solarbotics (wait, isn't it the other way around?) for
making a PDF file out Wilf's MS Word file. The Power Smart Head writeup
by Wilf Rigter is up for grabs in HTML, MS Word, and PDF format at

http://www.geocities.com/vityas/

Once, again, I encourage people to put it on their existing sites,
because I don't plan to keep that site up.

Cheers,

Victor


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