On 11/08/2012 02:18 PM, Tom Metro wrote: > relay control boards, but I'm thinking a TTL compatible reed relay, like: > http://www.nteinc.com/relay_web/reed.html > > wired to the parallel port (the server has one, and it is unused), and > controlled with some software, like parashell:
Those relays as you say are 5V min TTL compatible, did you check if your parallel port provides those voltages? Some 'newer' ones , specially laptops, give 3.3V, but since you are talking about a desktop it shouldn't be the case; a multimeter is your friend. The other concern is current draw: the first of those relays has typ. coil resistance of 200Ω , which would imply 10mA. It seems a bit high for a parallel port, which would require the transistor buffer that you mention. Honestly I feel that the opto-coupler solution would be simpler and less prone to mechanical failure and noise. Cheers, Nuno -- http://aeminium.org/nuno/ _______________________________________________ Hardwarehacking mailing list [email protected] http://lists.blu.org/mailman/listinfo/hardwarehacking
