--===============0785636292==
Content-Type: text/plain;
	charset="windows-1250"
Content-Transfer-Encoding: 7bit

I have a need for a cheap electronic water valve for an electronic squirt
gun I want to design for my son's tree houses. We have 2 tree houses
connected with a swinging rope bridge. 


I want to design electric squirt guns that shut off after so many seconds of
shooting. That way the boys cannot just shoot water at each other all of
time. It would be like reloading a real gun, it doesn't just fire all of the
time.

Irrigation valves for home sprinkler systems won't work as they are too slow
in their response.

Does anyone have any suggestions here?  I might design a pic circuit to
handle the on/off timing of the valves.



-----Original Message-----
From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] On Behalf Of
Russell McMahon
Sent: Tuesday, July 03, 2007 2:31 AM
To: PIC List
Subject: [EE]:: Electrically operated valve - home made idea

Here's a simple but reportedly effective way of producing a low cost 
electrically operated valve.

He uses a standard hydraulic valve, driven by what he says is an 
electrically operated pepper mill to provide the actuation. I've not 
seen such a mill here but an electrically operated coffee grinder 
would probably do the same job (and just may be what this is)(but 
probably isn't).

An electric battery  powered screwdriver would also be suitable. Such 
have 2 or 3 stages of epicyclic gearboxes to allow a relatively 
modestly sized electric motor to produce the very substantial torque 
required to turn screws. Actuation speed will depend on gearing and 
voltage used.

Performance is not mentioned on the web site but in an email to the 
ARocket list he says:

            > The 1/4" valve opens, at 50 bar, in 2/10 sec, on 9V.

That's reasonably impressive.
It may give the potato cannon people some ideas :-) - if they haven't 
been doing this sort of thing for years without me noticing.


            Russell



_________________

On the site he says:

This valve is the most recent I made. It's also the easiest to 
operate, probably the most reliable, and even though the cheapest. 
It's a 1/4" BSP hydraulic valve, connected to the mechanism of a cheap 
electric pepper mill (the kind you can buy at < $5). I made an 
aluminium frame that holds the two parts together; the torque is 
transmitted via a custom-made piece also. There is a small on/off 
switch that stops the motor when it has made a quarter of turn (not 
visible on the picture, it wasn't installed yet). One can probably 
replace it with a magnetic position sensor and thus get a throttleable 
valve.

This and a pyro and servo operated vales described here:

 
http://www.student.montefiore.ulg.ac.be/~teney/h2o2propulsion_actuatedvalves
.htm

Picture here:

 
http://www.student.montefiore.ulg.ac.be/~teney/h2o2propulsion/electroactuate
dvalve.jpg
-- 
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist

No virus found in this incoming message.
Checked by AVG Free Edition. 
Version: 7.5.476 / Virus Database: 269.9.14/883 - Release Date: 7/1/2007
12:19 PM
 

No virus found in this outgoing message.
Checked by AVG Free Edition. 
Version: 7.5.476 / Virus Database: 269.9.14/885 - Release Date: 7/3/2007
10:02 AM
 


--===============0785636292==
Content-Type: text/plain; charset="us-ascii"
MIME-Version: 1.0
Content-Transfer-Encoding: 7bit
Content-Disposition: inline

-- 
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist

--===============0785636292==--