The things that accept instructions from the controllers and translate those into changes in the real world (our effectors) come in several types, and some off these have more than one layer to them. Perhaps we can divide and conquer.
LED lighting fixtures are wired through drivers that convert AC power to the Voltage that the fixture wants to see. Our fixtures fall in the class that are dimmable through a 0-10 Volt control. The driver may normally be controlled by a wall switch, or by a combination of a wall switch and inputs from sensors that track things like ambient light or motion in a room, if not by a more complex automation system.
The image at the left adds one more element, a radio-linked control module directly wired to the driver. Modules like this can govern whether a light fixture is on or off, and whether it's at full brightness or dimmed to some lesser level.
These modules get their commands by radio from an interface that installs back in our controller infrastructure.
This gives us a way to effect changes in the on-off status and (for those lighting fixtures that support dimming) in the brightness of each and every light, indoors or out, with only a few exceptions. Those exceptions involve lights built into things like ceiling fans, where their control may be limited by the wiring connections and choices built into those products.
Routine electrical devices and electromechanical relays
Think of all the things you normally just turn on and off by flicking a switch or pushing a button: ceiling fans, for example, or cooktop exhaust vents or garage door openers.
The device at the right is an electromechanical relay, a mature technology that comes in all kinds of shapes and sizes with all kinds of capabilities, but for which the fundamentals are always the same: when you provide power to a relay, it uses that power to activate an electromagnet inside (a coil of wire wound around a ferric core) that pulls down an armature to cause groups of contacts to make or break electrical connections.
This close-up view shows the top of the coil, the arm and two button-shaped contacts, and allows us to make an important point.
Relays are inherently reliable as long as those contacts remain effective. The specifications of any relay include both current and Voltage ratings for its contacts. If you overdrive those contacts, they will degrade early and become unreliable. If you under-drive them, meaning if they are specified to be able to handle far more current and Voltage than you ever intend to connect to them, they should prove capable of the 40-year endurance that we set for the project. One way to do that, if we feel it is appropriate, is to let one relay drive another when the second has a higher power rating for its contacts.
The Ecovent System motorizes the ventilation register, affording 1000 extents to which each vent can be open or closed. These are intended to run on a quartet of AA cells each; we power ours from the 5 Volt DC lines in the house.
They have different designs for ceiling, floor and wall vents, each effective and each available in a choice of sizes.
They connect by a proprietary wireless link to the Ecovent (very) smart hub, which we can reach over WiFi.
This is our most complex collection of effectors.
All exterior doors get equipped with Schlage electrified locks.. There is no separate deadbolt and none is necessary. Instead, a spine along the back provides the same kind of stubborn stiffening.
The lock works in a sensible but, to many, unfamiliar way. A 24-Volt solenoid inside determines whether it is locked or unlocked. The inside knob has no hardware; you can always turn it to exit.
The outside knob can always open with a key (this model uses a 6-pin cylinder that's harder to bump, pick or drill open). If the door is not electrically locked, just turn the knob to enter. The key cannot change it from locked to unlocked., but it can always get the door to open.
A relay in parallel with the usual wall-mounted pushbutton switch (make that switches, since we are mounting those pushbuttons in 2 locations) acts like yet another pushbutton to command the garage door openers. And flashers like the one shown here are positioned over and just ahead of each garage parking space, shining first occasionally, then more rapidly, then constant on as a car comes to its appropriate parking position, finally turning off when the car stops moving.
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