Prototype light switch and dimmer 2016-04-12
BaanMaeLightingUtilities
0 Comment

I’ve been going around and putting finishing touches on the many projects that I’ve written about previously. I wrote previously about the custom solar powered LED light system that we built, but we hadn’t come up with a nice aesthetically pleasing design for a light switch and dimmer knob to control it.

So we hacked a Haco brand light switch box to do what we need it to do…

The dimmer knob is just a cheap encoder we bought off of eBay mounted on a “spacer” designed to separate the two switches. The switches are normal 220V AC light switches. The two switches and the encoder feed into the digital input pins of a microcontroller via a CAT5 cable coming out the top.

Here is a wider view of the bathroom at night with the lights turned on. The prototype light switch is on the left side:

The light switch is mounted slightly low so that my mother-in-law can easily reach it from a wheelchair, but it isn’t permanently screwed in yet. We want her to try it for a few days before finalizing this height. The blue CAT5 cable is just for testing the light switch. Once we finalize the height, we will cut a what CAT5 cable to the exact size and mount it to the wall. Also, we will try to source a nice plastic knob for the encoder that looks right. If not, we can always just 3D print something.

For the bathroom, the control interface is as follows (as determined by the programmed microcontroller firmware):

  • The right switch turns the lights on and off via the dimming algorithm described in a previous post
  • The middle knob adjusts the maximum “on brightness” of the lights if the lights are on
  • The left switch opens or closes a relay that drives the 220V AC bathroom exhaust fan
When using this light switch box for the bedrooms, I am planning to use the same switch and encoder configuration. But in the case of the bedrooms, the firmware logic will be as follows:
  • The left and right switches each turn on/off different sets of 4 LED lights using the same dimming algorithm (such as wall lights and ceiling lights)
  • The dimmer knob adjusts target “on brightness” of whichever lights are on, but does not affect the current saved “on brightness” level of left/right lights if the switch is off (which allows for a simple way to independently control two sets of lights with a single dimmer)
In addition, the DC LED light microcontroller board we’ve designed (with the help of pommm) supports two of these “2x light switch + 1x dimmer knob” boxes. This allows for 2-way switch logic in any room where it is desirable. I haven’t experimented with this yet, but it should be nothing more than an adjustment to the logic in the firmware. We’ve sent out the microcontroller PCB board design for printing and hopefully will have the first batch for assembly in a few weeks. 
After we have these lights set up in every room with one microcontroller per room, the plan is to connect all the microcontrollers via an RS485 bus so that there can be a “turn off all of the lights in the house because I’m leaving” type of control option also. Not to mention the possibility of a “let’s remotely set a schedule for lights on/off since I am on vacation and forgot to set it before I left”. 🙂
But this is still several steps away.
Then all I need to do is roboticise the opening and closing of the windows and doors and the house can be a full-fledged stationary robot…
(Which, of course, is several more steps further away.)
And since the plan for the floating house is that it will actually be autonomously mobile, we could be living in a autonomous mobile robot in about a year or so!
<HANDS RUBBING IN ANTICIPATION>
😉