Alt-BEAM Archive

Message #06659



To: beam@sgiblab.sgi.com
From: Sean Rigter rigter@cafe.net
Date: Mon, 11 Oct 1999 20:28:01 -0700
Subject: [alt-beam] Re: more info (was: how exactly does a bicore work?)


Hi Evan

The problem is probably floating unused inputs oscilating like crazy !
Connect all unused inputs and pins 1, 10 and 19 to 0V and pin 20 to +V.
The LEDs should be in parallel anode to cathode. Make sure you have a
1K to 2K resistor in series with the LED pair. Remove the PDs to check
the bicore operation by itself. Make sure you use 0.1 to 0.33 uf caps
and a 1M or higher resistor. The LEDs should alternate once per second..
Next add the PDs (in series!) anode to anode across the 1M resistor.
Note the on time of each LED is inversely proportional to the amount of
light on the corresponding PD. After that you can connect bicore to the
unused sections of the 240 used as buffers to driver to a small gear
motor. Let us know if you get stuck.

regards

wilf

Evan Dudzik wrote:

> hmm, that did nothing. PS i have them in parallel but
> opposite facing ways like the photodiodes are, and i
> tried flipping the things around thru all the combos
> of anode/cathode, and the LEDS still stay on. i have
> no idea what to do now. oh well, screw my crappy
> bicore, until someone can tell me how to make it work.
>
> --- JVernonM@aol.com wrote:
> > In a message dated 10/11/99 4:14:51 PM Eastern
> > Daylight Time,
> > evandude@yahoo.com writes:
> >
> > > both LED's on and off
> > > TOGETHER.. how can electricity flow both ways at
> > once?
> > > they were in opposite directions! (anode+cathode
> > > reversed, etc.) i have no idea how this thing
> > should
> > > work, i took out a photodiode and it blinked
> > slower,
> > > but they were still both going at once. i am
> > really
> > > comfused. can anyone help me?
> > Flip one of the LED's around. Anode to anode. The
> > power is reversing
> > directions via the inverters. It just looks like
> > power is going both ways.
> >
> >
> > See ya,
> > Jim
> >
> http://www.geocities.com/SoHo/Exhibit/8281/beamart.html
> >
>
> __________________________________________________
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