Geoffrey Wiseman

Home Reno Automation with Pi

We've got a home renovation coming up, and we've been talking about a project that I can do with a bit of home automation / maker / raspberry pi skills that I basically don't have currently. It sounds like fun, but I'm enough of a newbie to this space that I'm afraid that I don't know what I don't know.

The Project

We are going to have a series of recessed (pot) lights that run down the side of the house. We have a garage in the rear and a walkway in the front and a door in the middle. We'd like to have motion sensors at the back (facing back), the front (facing front) and maybe the middle, so that when you approach from the back, the pots come on starting at the back and working towards the front in sequence. When you approach from the front, the front one comes on and the sequence goes back. If you come out the door in the middle, the middle lights go on and then extend both directions towards the end.

It's a relatively simple project in concept -- but the devil's in the details, and this goes outside my area of expertise, so there may be problems I'm not anticipating.

Plans

There's at least two ways I could imagine making this work:

• "Smart" Devices
  • Find wireless (wifi / z-wave) smart devices that are outdoor suitable and support custom integration:
    • Motion detector
    • Recessed lightbulbs
  • Automate them with some home automation platform (e.g. hass.io) or code of my own devising.
  • To be honest, I'm not even sure there are good outdoor-suitable wireless/smart recessed-lighting bulbs or recessed-lighting fixtures.
  • I didn't find any on a quick search. I didn't even look at motion detectors or integration.
  • I can find indoor recessed lighting fixtures that might work, but waterproofed exterior ones seem more rare.
• Automation Controller
  • Regular potlights that are wired into a relay.
  • A set of relays that can be wired into an "automation core"
  • Motion detectors that can be wired into an "automation core"
  • An "automation core", some kind of platform that can connect to the hardware and run code I write (e.g. a Raspberry Pi)

My Background.

I'm a developer. Programming won't likely be the problem. I don't do a lot of C or Assembly these days, but I don't get the impression I'm going to have to do that here either. I haven't done any home automation programming, but that doesn't scare me.

I've done some hardware tinkering in the distant past -- breadboards, soldering, electical projects. I've also done home electrical work (fixtures, receptacles, running electrical and low-power wiring). I've built and assembled computers.

I've never touched a Raspberry Pi, a relay. I've never integrated a computer with motion sensors or lights.

The Questions

Mostly, I want to understand a couple of things:

• How doable is this?
  • Am I in for a world of pain? Is the technology involved just not mature enough to tackle this kind of project without discovering a host of problems I haven't yet imagined?
  • Or is this the kind of thing that someone with more experience than I in this space could whip up in a few days without having to think too hard about it?
• Which plan?
  • Anyone know good smart devices for this purpose?
  • If I make my own automation controller, is a Raspberry Pi the right path? Seems simpler for a software person than going down the Arduino-type path.
  • Other plans I didn't consider?
• What do I need to know up front?
  • I get the sense that if I get a pi, some relays that work with a pi, some motion sensors that work with a pi, and spend some time with this, I can validate it easily enough.
  • I assume I need to run all the pots and motion sensors to a central point where I can put the pi and some relays and whatever else I need.
  • If I don't do that fast enough, what do I need to know now that I don't already know?
    • Does it matter what motion sensors I use?
      • I'm sure it does, but ... what criteria do I need?)
      • Most of the Rapsberry Pi motion sensor combinations I can find are little PIR modules with no housing. This is for external use, so I'd ideally like to use a full outdoor motion sensor that already comes in a real housing
    • Do the pot lights matter? I assume not, they're just electrical devices hooked up to relays.
    • Does it matter that the sensors and pot lights won't be super-close to the pi?
      • Sounds like I might need to worry about noise on the motion sensor wires, which end up acting like antennas?
    • What do I need to know about relays?
    • Does it matter which Pi I use? I'm guessing that any of them would be more than capable.
• Is there a reasonable way to have an override switch that would let me choose between: on, off and pi-controlled?
  • Seems like if I had a switch between the power source and the relays, I could have an off-or-pi-controlled switch.
  • I could have a separate switch that runs in parallel with the relays so that each pot can draw power from either the relay or the bypass switch, but I'd need ... a N-pole single throw switch?
  • I could in theory have a three-position switch that is just an input to the pi that the pi could interpret as "on/off/motion"
• Where do I go to ask these kinds of questions? Sounds less complicated.
  • What's a nice friendly place for a newbie with a home automation project like this in mind to go get advice?