By: jason

jason — Sat, 28 Nov 2009 06:33:08 +0000

I decided to attach the servos to the dampers in my unfinished basement, so access wasn’t really an issue for me. Initially I did have the servos sitting free return, but got concerned about “what if” and attached a return spring. That worked, but the servos had to work pretty much 24×7 and that guarantees early failure. So instead I just put a little routine in the code to make sure that only X number of servos are actually being closed at any given time and I monitor the inlet and outlet temperature of my HVAC plenum to make sure I’m not overtaxing the system.
I used the DS18S20P 1-wire sensors from Dallas. Great little sensors that can support very long cable runs and, if you run your wires the right way, can use only 1 pin on your micro controller. I didn’t run the wires the right way and ended up in a star topology, as opposed to the preferred bus, which introduced a lot of timing issues. I could have inserted a funky FET amp into the 1-wire network to get all of the sensors working, but instead decided to cheap out and used 1 pin for each room of my house, so each room has it’s own dedicated, switched 1-wire network.
The programming on the arduino is all done in C and on the linux box it’s a combination of perl and shell. I had started work on V2 of this platform which contained humidity sensors, light sensors, XBee wireless to control opening and closing of blinds and a more flexible UI that would all overrides to be set on a room by room basis, but we’re having another baby and so pretty much all of the spare time has gone into getting the nursery/wife/etc ready. Still hope to make some headway, but no idea when.

By: jon

jon — Sat, 28 Nov 2009 05:01:20 +0000

I am looking to do the same thing to my home using a plc with an rtd card, the only thing that worries me is that you will need an access panel for the servos everywhere and what if the servo fails, it should return to normally open and be back in normal operations. what type of temp sensors did you use and cards. where did you get the hardware and is the programming done in c++? it would be nice for maint purposes to have the louvres at the registers but you would need a lot more io. and instead of everyroom close to the same temp have individual room setpoints for those who like their rooms cooler, or rooms that arent in use. same system works for sprinklers and moisture sensors

Comments on: Whole Home Information Awareness

By: jason

By: jon