Friday, June 06, 2014

LED lighting control boards

Woot! I just ordered a set of PCBs for lighting control in the new house. Wifey would kill me if we had no lights, so the priority kinda jumped on this one ... (*Wifey comments:  I wouldn't kill you.  However, I consider it prudent to go to Home Depot and buy some cheapo mechanical switches just in case)

One of the more unique things about my (upcoming) house is that the bulk of our lighting are LED 24 VDC cans/pots/recessed lamps(*). Ceilings fans, chandeliers, and watercloset light/fans are standard high-voltage AC, but the bulk of our electrical fixtures are using these nifty low-voltage lamps. One neat thing is that the lamps don't require AC/DC stepdown transformers, so their cost is dropped, their reliability increases, and their heatprint is lowered.

The wiring becomes both simpler, and more complex in ways, and possibly cheaper depending on your choices. Simpler because you can run standard 14 gauge stranded speaker wire (cheap; flexible around those corners) instead of the heavier gauge Romex stuff. The lower gauge wire can save you quite a bit on copper costs, and you can lose the heavy insulation and concerns of high-voltage wires in your walls. But much more complicated because you need special hardware to run them ... a repair is no longer just a run to your local Home Depot.

In my case, much of the wiring in the house has been "home-run" back to my server room, so I ended up doubling my copper/install costs. All the control is localized to that room, which also means I don't have actual "switches" in my house, but just sensors (see Capacitive Touch Wall Switches). This leads to "how do I control these lighting circuits?"

Thus, my custom PWM Control Boards. They have an embedded microcontroller which can "do anything" with the nine (9) output channels. A higher-level "upstream" controller will tell it what actions to perform, when, and how, communicating via TTL Serial or I2C or what-have-you. The boards sink current, at whatever voltage (so I will also use these for my 12VDC LED light strips).

I've sent the PCBs off to ITEAD for production. Between now and when they arrive, I'll finish the microcontroller work that I've been working on. Assemble some parts from Mouser, plug it all together, and LIGHTS!


Will report back, as I make progress...

(*) I decided not to name/link the manufacturer until I get experience and form an opinion. Just email me to ask, if you're interested.