Alt-BEAM Archive

Message #01102



To: beam@corp.sgi.com
From: "Ben Hitchcock" beh01@uow.edu.au
Date: Mon, 01 Mar 1999 19:35:48 +0000
Subject: [alt-beam] Re: photovore and walker update


>thought i'd have another go at making a photovore on a breadboard,
>but still, absolutly nothing, arghh! I'm concerned it may be the
>transistors, i'm using the bc type, i can get a 2n3904 but not a
>2n3906, any substitutes?

If you use the BC XXXB or BC XXXC type, then those transistors have a lot
higher gain than the plain old BC XXX type. These transistors work well as
voltage sensors. (I use BC549C, BC559C for this.)

For motor drivers, you need transistors that can handle high currents. I
use BC337 and BC327's.

Try the suneater 1 circuit if you still have problems. I have found it to
be very reliable. You can find the circuit by looking at the dragonfly on
my site, or by going to

http://people.ne.mediaone.net/bushbo/beam/suneater/suneater.html

>The walker's doing okay, the motor has to be
>tuned to get maximum efficiency, and the microcore, is very jerky,
>sometimes it goes but the slightest move of the power wire and it
>goes all screwy, oh well, better than it not working at all.
>

try the suggestion at:
http://www.wollongong.apana.org.au/~ben/info/isolation.html

This solved all my microcore woes.

Ben


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