Alt-BEAM Archive

Message #10498



To: beam@sgiblab.sgi.com
From: "Mike Kulesza" mikekulesza@hotmail.com
Date: Sun, 20 Feb 2000 15:27:08 GMT
Subject: [alt-beam] walker dying


I finished a walker last night, but for some reason, after everytime I turn
it on, it slows down stops altogether after about 10 seconds. The indicator
LED's also glow less bright. And I know its not the battery, because its
brand new... Here are the specs: Does anyone know what's wrong?

- Master-Slave Bicore with reverser (Ian's complete walker circuit)
- 74HC240
- 2 h-bridges
- 2 Lithium 3V batteries in series
- 7805 voltage regulator (bicore gets 5V, motors get 6V)
- 4 Green indicator LEDs
- 1 Red LED to show when the tactile sensor is turned on
- 2 .22 uF caps for each neuron = .44 uF per neuron
- Front and rear motors are different... but both efficient and alike in
performance.
- No filtering caps (o.1 uF across IC and/or motors)
- Entire circuit on a pcb (flux scraped off)

and thats about it.... thanks for the input, and especially for that on the
pager motor and fan.

______________________________________________________



10499 Sun, 20 Feb 2000 12:59:37 -0500 [alt-beam] newbie electronics questions beam@sgiblab.sgi.com walkau i just finished reading the Smithsonian article and have become a BEAM
believer however my electronics knowledge is not up to speed yet.

i had some questions about the SE circuit that i would appreciate some
help with.

i have some small 3v motors kicking around (i don't know what the
current draw is) and some small 3v 1.5 ma solar cells with which i would
like to build some SE.

what rating of capacitor should i be using? i am not sure of the
significace of the farad rating on the capacitor. i understand the need
for the voltage rating on it.

should the voltage rating on the capacitor be comparable to the motor?
or should it be greater than the motor's voltage?


many thanks

niels walkau



10500 Sun, 20 Feb 2000 13:57:38 -0400 [alt-beam] BEAM yahoo chat "alt-beam@egroups.com" michael.hirtle@ns.sympatico.ca (Michael Hirtle) Hi all.
Is there a Yahoo chat on tonight?
If no one has called a chat for tonight yet I would like too.

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