Date: Fri, 2 Nov 2007 15:11:02 +0300 From: Achilleas Mantzios <achill@matrix.gatewaynet.com> To: freebsd-hardware@freebsd.org Subject: Implementing a "normally open" relay Message-ID: <200711021411.02488.achill@matrix.gatewaynet.com>
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Hi, i am building a home security system based on zoneminder under FreeBSD 6.2. I think i have it all sorted out, except a way to drive an external alarm upon camera motion. I have set up the alarm panel with an additional zone, which corresponds to an EOL circuit terminating to a 47Kohm resistence. When i join the ends together i can see the light of the xmitter flashing, so the electric part is ok. (all the above with a powermax+ system, the EOL loop is attached to a magnetic contact, connected to its aux. input). I have the LMLBT4M card from linux media labs, which i managed to make it work with Zoneminder. This card supposedly has a GPIO feature, allowing it to control a "normally open" circuit. So i wrote a program to drive the GPIO bits but unfortunately i dont see it on the electric level. The circuit never closes when i attach the wires to the DB15 pins (11,12) and write the corresponding word to the GPIO data register. So what is left for me is to abandon the GPIO idea and find another way to do this: Have two states: a) (normal) Have the two wires isolated from eachother, ground, voltage b) (alarm) Connect the wires together (shortcircuiting the EOL). Could it be done someway with /dev/cuad* /dev/lpt* Many thanx for any hints. P.S. Please include my email address to your reply. -- Achilleas Mantzios
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