Alt-BEAM Archive
Message #08876
To: "'beam@sgiblab.sgi.com'" beam@sgiblab.sgi.com
From: Wilf Rigter Wilf.Rigter@powertech.bc.ca
Date: Thu, 6 Jan 2000 20:57:19 -0800
Subject: [alt-beam] SIMPLIFIED D1 CIRCUIT
Hi Jim,
I hope this circuit will shine a little light on your D1 problems. Consider
using this simplified D1 (SIMD1) type solar charger /darkness trigger. It
uses 1/6 of a 74HCT14 with the remainder used for pummer, microcore, etc.
If the rest of the hex inverter 74HCT14 chip is not used, then a single
74HCT14 inverter chip may be used instead, which is about the same size as
the original 2N7000. The cap C1 can be a gold cap or if the current
requirements are not high (ie pummer), one of the higher voltage/higher
impedance coin type supercaps would be just fine. Alternately C1 can be
replaced with a suitable NiCad battery. At dawn and throughout the day the
SIMD1 will charge the cap/battery and then will turn on the circuit it
controls at dusk and stays on until the cap/battery is discharged. The D1
will trigger at the lower (+V/3) threshold of the Schmitt trigger and with a
74HCT14 that point may be as low as 10% Vmax open circuit of the solar cell.
The SIMD1 "snaps" on when the solar cell is dark and will only reset at a
much higher light level or when the cap/battery is deeply discharged because
of the Schmitt trigger hysteresis. The diode (D1) can of course be replaced
with the more efficient ZVD circuit.
enjoy
wilf
<>
> -----Original Message-----
> From: JVernonM@aol.com [SMTP:JVernonM@aol.com]
> Sent: Sunday, December 19, 1999 12:28 AM
> To: beam@sgiblab.sgi.com
> Subject: Re: NiCads...
>
> In a message dated 12/19/99 2:23:47 AM Eastern Standard Time,
> flytch@hotmail.com writes:
>
> > I for one am very interested... I am building my house right now so I
> have
> > little time for experimentation... But I am! building in a beam park in
>
> the
> > living room window...
> Good for you! I wish I could do that myself. I have a plan for a BEAM park
>
> that will be great if I ever get to it. I do need to do something though,
> I've built so many bots that I have no where to keep them. I don't want to
>
> stick them on a shelf to gather dust, after all, the whole idea is to
> enjoy
> them. As to the power issue, if I get anywhere I'll post my findings. A
> combination of the D1 and a good day time solar engine sounds like the
> ticket. I've tried the D1 with up to a 10F cap and the performance is very
>
> disapointing. On my Jasmine plant I only get about half an hour of
> blinking 8
> micro LEDs. I would imagine a Unicore (which I think is the best candidate
>
> for this) with two gearmotors, would drain that 10F cap in just a few
> minutes, no good (besides, it's as big as one of those personal juice
> cans,
> and gets a full charge from the large solar cell in under an hour of full
> sun). The logical solution is a battery pack instead of the cap. The only
> problem that I anticipate is setting the "on" level of the D1. The range
> of
> coming on to soon versus not coming on fully is very small. Also, I'm not
> sure about using the solar cell as the light sensor (as the D1 does),
> seems
> that a good ole CDS cell would be more sensitive and tweekable. I envision
>
> bots that work constantly. Day or night, no matter the light level.
> Assuming,
> of course, that the critter gets some sun during the day. I thought of
> this
> while watching my Jack Russell Terrier playing in the yard. He has an
> almost
> inexhaustible supply of energy. A vast reserve used to play, explore, and
> get
> into trouble. Then, I thought, the robots we build have no such reserve.
> They
> eat and move, eat some more and move some more. No food, no motion. We
> emulate biologicals, but have never considered a power reserve for
> sustained
> operation or frivolous use. Our bots are anorexic! They need some fat to
> get
> them through the night. Imagine how much more useful a window cleaner or a
>
> sweeper bot would be if it never stopped. We have come to refer to the non
>
> operational time as sleep time. But, sleep time is usually associated with
>
> recharging ones energy reserves. The sleep time that we often refer to
> (outside of the time it takes for a super cap to fire, and really, that
> should be called eat time) is really dead time. They are dead as a door
> nail.
> A bot with a power reserve would also keep a microprocessor "rider" going
> as
> well, allowing for more complex behavior. It seems like the natural next
> step
> to me. Sorry for the book, I'm just excited that someone mentioned the
> idea!
>
> See ya,
> Jim
> http://www.geocities.com/SoHo/Exhibit/8281/beamart.html
> ICQ# 55657870
Attachment: SIMD1.gif
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