Alt-BEAM Archive

Message #03246



To: Richard Piotter richfile@rconnect.com
From: Bruce Robinson Bruce_Robinson@bc.sympatico.ca
Date: Thu, 13 May 1999 16:28:09 -0700
Subject: [alt-beam] Re: Underwater motors (was Motors)



--------------D415497AD3CC9B0003B9D364
content-transfer-encoding: 7bit
content-type: text/plain; charset=us-ascii

Richard Piotter wrote:
>
> ... If the sides were simply a thing layer of silicone holding it
> together, and the valves were on front and back, then you'd get a bit
> of forward motion fron extending the magnet too, from watter being
> drawn in from the front!

You'd probably be disappointed by the forward motion from sucking water
into the lung. The sucking action draws water from all around the
opening, and only a small part of that is in front of the lung. On the
other hand, the squeezing action tends to shoot out a jet of water
directed mainly at the rear, so the pushing action is much more
effective.

You can enhance the pushing action by using a short tube to focus the
jet even more.

But here's the best part. Because sucking water in gives you far less
motion than blowing it out, you don't need two valves! In fact, you
don't need any valves. Just a small bladder with a tube pointing to the
rear. Alternately squeeze and expand the bladder: it will shoot forward
on the squeeze action, and drift back only slightly on the expandind
action.

So just use Nik's magnetic design on a small bladder with one opening
pointed to the rear, and you can't bet much simpler. Use two bladders
and you've got steering.

So where do you get ready-made bladders, complete with attached tubes?
Toys is where. Attached is an image of a "squeaky toy" my daughter
bought our dog a few years ago. The only part that survived was the
"squeak" -- a small bladder with a tiny plastic whistle pressed in the
neck. Just pry out the whistle and you have a small ready-made lung.

Regards,
Bruce


>
> Great image too!!!
>

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


--------------D415497AD3CC9B0003B9D364

Attachment: bladder.jpg

--------------D415497AD3CC9B0003B9D364--



3247 Thu, 13 May 1999 16:54:37 -0700 [alt-beam] Re: Printers Dennison Chiu-Yuan Fang http://www.geocities.com/SouthBeach/6897/rigter/wr_1.html#jan18

Wilf posted this message about driving steppers.

Chiu

Dennison wrote:
>
> Printers do have nice motors. Not nessesarilly nice for BEAM bot's but nice
> stepper motors. Which you can always stockpile and use oneday when you get
> up the nerve. Speaking of which, I know we got a stepper driven by a U-core
> but wasn't that just one direction? Anyone have a forward/reverse stepper
> motor driver? That would be really usefull, figuring as stepper motor driver
> chips ain't cheap.
>
> dennison
>
> >Hi list,
> >
> >Quick question. Do old tractor-feed printers have decent motors? The
> thrift
> >store in town here has a pile of them.
> >
> >Wondering Aimlessly,
> >James
> >

--
Chiu-Yuan Fang
chiumanfu@home.com
ICQ=5614919
http://www.geocities.com/SouthBeach/6897/beam2.html

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

Home