Home Automation #1: Smart Home Musings

Blog entry by Dan Lyke posted 01-14-2013 07:38 PM 3911 reads 0 times favorited 6 comments Add to Favorites Watch
no previous part Part 1 of Home Automation series no next part

Over this Christmas break, Charlene said “why don’t we start replacing the knob and tube with those two lights”. We did, and then started on the next light, and in the process of tearing that apart at midnight I said “screw it, I’m taking tomorrow off and we’re going to re-do all the lights”.

So we did: removed all vestiges of knob and tube and replaced it with modern wiring, Romex, a little bit of THHN in conduit for the exposed parts; replaced light fixtures; beefed up the ceiling fan mount. Just reworked the whole damned thing.

Three major changes have come from this:

  • When we moved in, we had a breaker panel installed to replace the fuse box, and in the process our doorbell transformer got disconnected. I tripped over the wires for that and was inspired to try to find a replacement that wasn’t a cheesy plastic battery powered wireless doorbell.
  • We finally broke down and put a real fan/heater combo in the bathroom.
  • We also got (haven’t installed it yet) a temperature controller for the ceiling fan.

All of this has inspired a fit of “we should improve how the house behaves!” gusto in us. In particular:

  • I learned that doorbell transformers draw 3 watts at idle. Modern switching power supplies (“wall warts”) draw almost nothing if they’re not being drawn on, and for a watt and a half I can put a Linux computer up in the attic. So I’ve ordered a couple Raspberry Pi embedded Linux devices, and need to find reed switches to put sensors on all of the doors, and maybe drop a few webcams in appropriate locations too.
  • We put the standard switch on the heater, and a timer too so that we can set it to 15 minutes after our shower to dry out the bathroom, but we got to thinking it’d be really nice to be able to grab a cell phone or a tablet when we’re lying in bed and switch on the bathroom heater, just like we can already kick on the water recirculator so that the shower is hot when we get there.
  • The temperature controller for the ceiling fan looks… fine…, but has a separate remote. We’re a pretty wired household, we each have a laptop, a tablet, and a smart phone. Why add yet another silly things with buttons to the mix?

So I’m trying to dig further.

The previous owner had put some ceiling speakers in that we haven’t removed yet. With the Raspberry Pi, all we need is a simple amplifier to drive those. I could build one, or hopefully find something fairly cheap that I can plug in to the audio out of the computer. I probably have one in the parts drawer that’d drive a single 8Ω speaker, I’m not sure how loudly or with what fidelity. Long-term, we think it’d be cool to drive a couple of solenoids hitting some physical audio sculpture. We’ll see where we get.

I’m trying to figure out how to reasonably switch the 20A circuit for the bathroom heater. There are X10 and Insteon modules that will switch 20A (and I have to be careful, many timers and smart home switches will just switch 2A or 3A, small lighting circuits) but I’m running into enough potential issues with trying to debug Insteon that I’m not sold. I may have to just see if someone has a UL approved relay assembly I could drive with one of the TTL outputs or a USB port on the Pi.

Similarly, the ceiling fan has lower loads, but maybe using a 1-Wire button to sense temperature and switching the fan and lights in the living room with the Pi might make sense.

Finally, I’ve often thought that it’d be cool if I could control the doors, both entrance and garage, with my smart phone, or with one of the many RFID cards I already have in my pocket (office/work door key, my transit Clipper card, etc). The garage door is easy, just a transistor, resistor or two, and a few protection diodes off of one of the Pi TTL outputs., but the others will require an RFID reader and a couple of solenoid driven strike plates.

Anyway, problems to be solved, I’ll use this series as a place to throw ideas and discoveries up as I implement them.

-- Dan Lyke, Petaluma California, http://www.flutterby.net/

View Dan Lyke's profile

Dan Lyke

338 posts in 3732 days

Entry tags/keywords

electrical musings

View Blog Archive
Subscribe to blog entries (RSS)

By subscribing to the RSS feed you will be notified when new entries are posted on this blog.

Recent Entries

6 comments so far

View Karson's profile


97 posts in 3713 days

posted 01-14-2013 08:07 PM

Looks like you are getting hooked up like Bill Gates, But he probably is not worried about a few thousand watts here and there.

-- Retired in Delaware

View Dan Lyke's profile

Dan Lyke

338 posts in 3732 days

posted 01-14-2013 09:55 PM

We have a number of absurdities that’ll never pay off in search of a watt or two of savings. Which is interesting, because one of the things that annoyed me about the building inspections of my workshop is that they made me put motion and light detectors on my exterior lights. Long story there…

But I’m also a computer geek and a big believer that we have too many interfaces to our environment, and I’m embracing the opportunity to try to build this into a system that can understand and work with me to help me have to do less to tell my house what I want it to do around me.

-- Dan Lyke, Petaluma California, http://www.flutterby.net/

View MsDebbieP's profile


629 posts in 3746 days

posted 01-15-2013 08:14 AM

oh how I wish I was knowledgable about electrical stuff. Of course, then I’d be very aware of all the wasted power and I’d have to change it all. Now, I’m just “mildly aware”.
And oh how I’d love to have a doorbell. ... and the ability to heat up the water for the shower before heading that way….
and to be able to change all the wiring in one day!!!!

-- ~ Debbie, Ontario Canada

View Dan Lyke's profile

Dan Lyke

338 posts in 3732 days

posted 01-15-2013 03:19 PM

The wiring wasn’t one day, this has been a several day process, and we’ve really just tackled the lighting up ‘til now, but…

Our hot water recirculator is a Metlund D’Mand, chosen because it let us mash a button to use it and wasn’t on all the time (like the Watts and others). And installing that is a matter of disconnecting the feed lines in fixture furthest from your heater (in our case, under the bathroom sink), and reconnecting them through the water heater. Poof, instant “press a button get hot water when you stumble in to the bathroom”.

On being aware of wasted power, many libraries these days are loaning out Kill-A-Watt meters, and if not they cost about $60(US), and easily tell you how much those cell phones are drawing. Spoiler: Aside from climate control (ours is gas), your refrigerator and washer and dryer are probably the biggest users, at least if you’re like us and have switched to Compact Fluorescent and LEDs for your lighting.

-- Dan Lyke, Petaluma California, http://www.flutterby.net/

View MsDebbieP's profile


629 posts in 3746 days

posted 01-15-2013 03:42 PM

re: energy
I bought a pressure canner this past fall (and love it). My goal is to eliminate the need for a freezer. Since I own two, that will be a BIG savings in electricity.

the hot water thingy “sounds” so simple, the way you describe it.

-- ~ Debbie, Ontario Canada

View Chris Mobley's profile

Chris Mobley

32 posts in 1956 days

posted 02-12-2013 04:00 PM

Very neat information.
Thank you!
Chris Mobley

-- Chris Mobley - www.cmobleydesigns.com

You must be signed in to post the comments.

DISCLAIMER: All views and comments posted by members are not necessarily those of HomeRefurbers.com or of those working on the site.

Latest Projects | Latest Blog Entries | Latest Forum Topics

LumberJocks.com :: woodworking showcase