Re: gEDA-user: Power relay question

[mjarabek@xxxxxxxxx]

Hi,

   One additional safety note... Add a second limit switch past the first one. Wire the second one so it blows the fuse if tripped.  That way, if your controller stops working for whatever reason, the motor will only run past the first limit switch once, before failing safely.  Think of it as a hardware 'Assert()'. 

   I once saw a rescued turn of the century clock mechanism ruined because the folks who designed the automatic winder for the counterweight didn't do such a simple trick...

Thanks,
Mike
-----Original Message-----
From: DJ Delorie <dj@xxxxxxxxxxx>
Sender: geda-user-bounces@xxxxxxxxxxxxxx
Date: Thu, 28 Jul 2011 18:04:41 
To: gEDA user mailing list<geda-user@xxxxxxxxxxxxxx>
Reply-To: gEDA user mailing list <geda-user@xxxxxxxxxxxxxx>
Subject: Re: gEDA-user: Power relay question


This is the type of problem that just screams "PIC10 !!"  :-)

The lower cost of the simpler relay would easily pay for the logic
chips, and you could add in some safety features and debouncing for
free.

Then dump the relay and use a power MOSFET :-)

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=PIC10F200T-I/OTCT-ND
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=IRFML8244TRPBFCT-ND


_______________________________________________
geda-user mailing list
geda-user@xxxxxxxxxxxxxx
http://www.seul.org/cgi-bin/mailman/listinfo/geda-user



_______________________________________________
geda-user mailing list
geda-user@xxxxxxxxxxxxxx
http://www.seul.org/cgi-bin/mailman/listinfo/geda-user