Alt-BEAM Archive

Message #03193



To: "Matt Procopation" proc@home.com
From: "Nigel Joyce" nigel.joyce@qr.com.au
Date: Tue, 11 May 1999 15:59:50 +1000
Subject: [alt-beam] Re: Photodiode question


From the layout you supplied, I recon, Try it, see what happens
also if you have the anode and cathode facing the same way
you know that if it does have a more sensitive side then both PD's
will be equally effected. I have PD's that obviously have a sensitive side
because the plastic around them is shaped to focus the IR onto the
right place inside the diode.

I also have been fooling with FLED photopoppers and have not found that mine
is not very photophilic either, just sort of whichever FLED decides to fire
first
Got to get that trim working properly };-)

[] []
/ \ / \
a c a c

(a=anode, etc)

Hope this helps
Cya &
Blue Skies
---Buzz---
>
> I've got this FLED photovore (from the schematic that's been
> floating around the mailing list lately) popping around on my
> desk, and it appears that it's not acting photophilic at all.
> When I breadboarded the circuit, it seemed to work just fine,
> but since it's been given a body, it just goes whereever it pleases.
> At first I thought I might just have the motor leads backwards,
> and that it might be photophobic, but it doesn't look like it.
> The only thing that I can think of is that the photodiodes don't
> have the same face pointing forwards.
> Looking head on at the bot, they're arranged like-
>
> [] []
> / \ / \
> a c c a
> (a=anode, etc)
>
> Now, these aren't solarbotics-type photodiodes; they don't
> have one face that is obviously rounded, they're basically
> symmetrical rectangular prisms.
> So, do photodiodes usually have one face that is the most
> sensitive? If so, I probably just need to flip one of them around.
>
> _ _
> Matt


------------------------------------------------------------------------
eGroup home: http://www.eGroups.com/group/alt-beam
http://www.eGroups.com - Simplifying group communications

Home