Category Archives: Home Automation

Home Automation, part 2: Z-Wave and ISY programming

In my part 1 post yesterday, I wrote about the start of the home automation project. I mentioned that I was using Insteon switches, and they mostly were working well (I forgot to mention an annoyance: you can dim, but not totally shut off, their LED status light.) Anyhow, the Insteon battery-operated sensors seem to not be as good as their Z-Wave competition.

Setting up Z-Wave

Z-Wave devices get joined to the Z-Wave network in much the same way Bluetooth devices get paired with each other. The first time you use a Z-Wave device, you join it to the controller. The controller assigns it an ID on your network, and both devices discover the best route to communicate with each other.

I discovered that the Z-Wave module on the ISY-994i has particularly poor reception. Combined with the generally short range of battery-operated Z-wave devices, this meant that my sensors didn’t work reliably. As with Insteon, AC-powered Z-wave devices tend to be repeaters, but I didn’t have any AC-powered Z-wave devices. I went looking for Z-wave repeaters, and found some. But then I discovered that a Z-wave relay-based appliance switch was actually $5 cheaper, acted as a repeater, and could be used as a switch down the road if needed. A couple of those solved my communications issues. You join them to the network as usual, but then either re-join the battery-powered sensors (so they see the new route) or do a “network heal” (every device on the network re-learns about its neighbors and routes to the other devices) so they see the new route.

Z-Wave Motion / Occupancy Sensors

If you have been in new buildings, chances are you have seen light switches with built-in occupancy sensors. My doctor’s office has these. They are typically the same size as a regular light switch, but with a passive infrared (PIR) motion sensor used to automatically turn the lights off after a timeout (or even on, when someone walks into the room.) These work fine for small rooms, but if you’ve ever been in a bathroom with a PIR lightswitch that goes off while you’re still in the room, you are aware of their faults for larger rooms!

Most of the time, when you read about “occupancy sensors”, it’s really a PIR sensor, and the term is used interchangeably with “motion detector.” Motion detectors in home automation systems are commonly used for a number of purposes: detecting occuption of rooms for automatic control of lighting or HVAC systems, triggering alerts, or even locking or unlocking doors.

My friend told me he had poor luck with the Insteon PIR sensors, so I tried two different Z-Wave models: the $48 Aeon/Aeotec multi-sensor and the $30 Ecolink PIRZWAVE2-ECO. The Aeon device is clearly the more capable; it can be used indoors or out, and has a lot of options that can be configured by Z-Wave configuration parameters. It also has a ball/socket mount, so it can be easily aimed in different directions. It can draw power from 4 AAA batteries, or a mini USB cable (cable, but not power supply, included). The Aeon multi-sensor also has a temperature, humidity, and illumination (lux) sensor – but, as you’ll see, they have some drawbacks.

The Ecolink device is more basic; it has a few settings that can be altered via jumpers, but none that can be altered via Z-Wave configuration commands. That makes it a bit of a hassle, since you have to open it up to change, and when you do, it triggers a “tamper alarm” that is both undocumented and never seems to go away. It is powered by a single CR123A 3V Lithium battery, which are about $2 each on Amazon.

Both units have a default PIR timeout of 4 minutes. That means that after sensing motion, they will transmit the “on” signal (meaning motion detected) and then transmit no further signals for at least 4 minutes. This is because operating the radio consumes far more battery power than simply monitoring the PIR sensor, and it cuts down on repeated on/off transmissions. In this configuration, both units should have battery life of 6 months to a year, I figure, with an edge for the Ecolink, perhaps.

Both can also be configured to transmit more frequently; the Ecolink has a jumper that can change its timeout to 10 seconds, whereas the Aeon can be configured over Z-Wave for any timeout between 10 seconds and 65535 seconds (values above 4 minutes are rounded to the nearest minute, for some reason.)

Both also have adjustable sensitivity; on the Aeon this is via an adjustment knob, and on the Ecolink it’s via jumpers. And both can report their battery level to enable software alerts when it’s getting low.

The Aeon ships with its temperature, humidity, battery, and lux sensors disabled. This appears to be the cause of much confusion online, as they send one transmission and then no more. Sadly, one has to resort to the hard-to-find but very helpful MultiSensor engineering spec document to figure out the way to enable those sensors and set their interval. (It must be said, however, that I doubt most consumers will understand how to set bitfields, and this is either not covered or covered incorrectly in their other manuals.) This can be a real power drain, so I just set it to report battery level every 6 hours (so I can alert myself if it gets low) and leave it at that.

The Ecolink manual claims a detection radius of 39 feet and a total angle of 90deg (45deg left or right from center) and a 3-year battery life (I’m skeptical). It also is rated for indoor use only. Aeotec claims a detection radius of 16 feet and a total angle of 120 deg. Be skeptical of all these figures.

Once set up with good reception, both devices have been working fine.

Programming the controller

The ISY-994i-Zw Pro controller I mentioned in Part 1 has its own sort of programming language. It’s a lot better than the sort of GUI clicky mess that is found in most of these things, but it still has a sort of annoying Java-based editor where you select keywords from a menu and such. Although you can backup and restore the device, and import and export the programs, the file formats are XML and not really suitable for hand-editing. Sigh.

The language is limited, but gets the job done. Here is a simple program that turns off the fan in a bathroom 30 minutes after the light was turned off:

        Status  '1st Floor / Bathroom + Laundry / Main Bath Fan' is On
    And Status  '1st Floor / Bathroom + Laundry / Main Bath Light' is Off
        Wait  30 minutes 
        Set '1st Floor / Bathroom + Laundry / Main Bath Fan' Off
   - No Actions - (To add one, press 'Action')

The if/then/else clauses should probably be more properly called when/do/finally. The “if” clauses are evaluated whenever a relevant event occurs. If the If evaluates to true, if executes the Then section. The program in “Then” is uninterruptible except for “wait” and “repeat” statements. So in this case, the program begins, and if the light stays off and the fan stays on, 30 minutes later it turns off the fan. But if the light comes back on, the program aborts (since there is nothing in “else”). Similarly, if the fan goes off, the program aborts.

A more complicated example: motion-activated lamp

There is a table lamp in our living room controlled by Insteon. By adding a motion sensor in that room, it can be automatically turned on by someone walking through the room. Now, to be useful, I don’t want it to turn on during the day. I also don’t want it to turn on or adjust itself if other lights are on in the room, or if I turned it on myself; that could cause it to go on and off while I’m watching TV, for instance. It’s just to be helpful at night. Because the ISY-994i is pretty limited, having almost no control flow operations, this — as with many tasks — requires several “programs”.

First, here’s my “main”:

        Status  '1st Floor / Living + Dining Room / LR Table Lamp' is Off
    And $LR_Lamp_Lockout is 0
    And Status  '1st Floor / Living + Dining Room / ZW 005 Binary Sensor' is On
    And From    Sunset 
        To      Sunrise (next day)
    And $LR_Lamp_Motion_Working is not 0
    And Status  '1st Floor / Living + Dining Room / LR Floor Lamp' is Off
    And Status  '1st Floor / Living + Dining Room / Dining Light' is Off
    And Status  '1st Floor / Living + Dining Room / LR Light' is Off
        Set '1st Floor / Living + Dining Room / LR Table Lamp' 22%
        Set '1st Floor / Living + Dining Room / LR S Remote (Table Lamp)' 22%
   - No Actions - (To add one, press 'Action')

So, let’s look at the conditions. This program triggers if the lamp is off, the sensor is on, the time is between sunset and sunrise, and three other lights are off. (I will explain the lockout and motion_working variables later). If this is the case, it sets the lamp to 22% (and also informs the wall switch for it that the lamp is at 22%). I pick this precise value because it is unlikely I would manually set it via the wall switch, and therefore “lamp is 22% bright” doubles as a “lamp was turned on by this program” flag.

So this is the turning the lamp on bit. Let’s look at the program that turns it back off later:

        Status  '1st Floor / Living + Dining Room / LR Table Lamp' is 22%
    And (
             Status  '1st Floor / Living + Dining Room / ZW 005 Binary Sensor' is Off
          Or $LR_Lamp_Motion_Working is 0
          Or Status  '1st Floor / Living + Dining Room / LR Light' is not Off
          Or Status  '1st Floor / Living + Dining Room / LR Floor Lamp' is not Off
          Or Status  '1st Floor / Living + Dining Room / Dining Light' is not Off
        Wait  15 seconds
        Set '1st Floor / Living + Dining Room / LR S Remote (Table Lamp)' Off
        Set '1st Floor / Living + Dining Room / LR Table Lamp' Off
   - No Actions - (To add one, press 'Action')

This is using a sensor with a 4-minute timeout, so the lamp will always be on for at least 4 minutes and 15 seconds. This program runs if the lamp is still at the program-set level (so if, for instance, I turned the lamp full on, the program does nothing to override my setting.) Then, it looks for a condition to trigger turning the lamp off, which could be any of the sensor indicating no more motion, another program detecting it’s lost communication with the sensor, or somebody turning on one of the bigger lights in the room. Then it simply sets the light (and the wall switch controlling it) to off.

There are a couple more bits to this puzzle. What if the system turned the lamp on, but I really want it off? If I walked up to the wall switch and pushed “off”, the lamp would go off. And then, a couple seconds later, come back on, since the state of the system met the conditions for the lamp-on program. So we need a lockout that prevents this from happening. Here’s my “trigger lockout” program:

        Control '1st Floor / Living + Dining Room / LR Table Lamp' is switched Off
     Or Control '1st Floor / Living + Dining Room / LR Table Lamp' is switched Fast Off
     Or Control '1st Floor / Living + Dining Room / LR S Remote (Table Lamp)' is switched Fast Off
     Or Control '1st Floor / Living + Dining Room / LR S Remote (Table Lamp)' is switched Off
        $LR_Lamp_Lockout += 1
        Run Program 'LR Lamp Clear Lockout' (If)
   - No Actions - (To add one, press 'Action') 

So if someone pushes the “off” button at the lamp switch box at the outlet it’s plugged into (unlikely), or at the wall switch, it increments the lockout variable and runs another program. This other program is unique in that it is flagged “disabled”, meaning it is never run automatically by the system, only when called by another program. Here’s the clear lockout program:

        $LR_Lamp_Lockout > 0
        Wait  5 minutes 
        $LR_Lamp_Lockout  = 0
   - No Actions - (To add one, press 'Action')

Thus by pushing the “off” button on the switch, the motion-triggered program won’t turn the lamp back on for at least 5 minutes.

Before I had reliable Z-Wave communication to the device, I had some times where it would simply drop off the Z-Wave network until a reboot. This was particularly annoying if it occured after having detected motion, since the state of the sensor in the ISY controller is simply whatever state it last received. Therefore, I wrote this program to check if it believes the motion sensor is working:

        Status  '1st Floor / Living + Dining Room / ZW 005 Binary Sensor' is On
        $LR_Lamp_Motion_Working  = 1
        Wait  1 hour 
        $LR_Lamp_Motion_Working  = 0
        $LR_Lamp_Motion_Working  = 1

We don’t really care if the motion sensor is broken when the status is off; all that happens then is no lamp turns on. So this program activates when the status is set to on. It flips the working flag to true, then waits for an hour. If the sensor shows no motion within that hour, the program skips to the else (keeping the flag true). But if it is still on after an hour, it decides “it must not be working” and sets the working flag to false. You can see that flag used in the other programs’ logic. But because of the Else, which is run whenever the conditions that caused the Then clause to run become false, as soon as the system receives “no motion”, it will flag the sensor as working again.

The final piece to this puzzle is a program flagged to run at boot time of the controller:

   - No Conditions - (To add one, press 'Schedule' or 'Condition')
        $LR_Lamp_Motion_Working  = 1
   - No Actions - (To add one, press 'Action')

This simply initializes the motion working variable to a known state.


The Insteon KeypadLinc is a nice device. It can control a single load directly, but all 8 buttons are fully responsive in the Insteon system. They each also have individually-addressible LED backlights. They are commonly used to do things like “ALL OFF”, “TV” (to set lights for watching TV), “AWAY” (to set the system for everyone being out of the house for awhile), etc. They are the size of a regular Decora switch, and I have installed one already, but haven’t programmed much of it yet.


The ISY has an extensive REST API, which I’ve used to integrate it a bit with my Debian systems. More on that another time.

Mobile app

Mobile apps are a common thing people look for in these systems. You can’t use the Insteon app with the ISY, but they recommend Mobilinc Pro. It does the job. Mobilinc tries to sell a $10/mo connection service, which is totally unnecessary if you can figure out SSL, and has on-screen buttons to bypass, but judging by the Google Play reviews, a lot of people thought they had to pay for that and uninstalled it afterwards.

Future directions

Many people put in electronic door locks. I don’t plan to do that. I do plan to have the house systems be aware of the general state of things (is the house empty? is everyone asleep?) and do appropriate things with lighting and HVAC. I don’t really expect the savings in power for lighting control to pay for the system anytime soon. However, if it can achieve some savings in heating and cooling, it may well be able to pay for itself in a few years. So my big next step is thermostats that can integrate with all this.

I have had a water mess in my basement before, and water leak sensors are a very common item people deploy in these setups. I certainly plan to add a few of them.

Door-open sensors are also useful; they trigger more instantly and reliably than motion detectors and can be used in some nice ways (is it after dark and the door is opening when the house is vacant? If so, turn on the light nearby in case their hands are full.)


Some issues I ran into so far are already discussed above. One other major one involves SSL on the ISY-994i Pro. The method for adding SSL keys is cumbersome, but the processor on the device — which appears to run some sort of Java — is just not up to working with SSL. Apparently they only recently got it fast enough to work with 2048-bit keys. This is rather undocumented, though, so I obtained a cert for a 4096-bit key, my usual. Attempting to connect to the box with SSL appeared to hang not just that but confuse a lot of other things on it as well. Turned out it wasn’t hung; it just too a minute and 45 seconds to complete the SSL handshake. Moral of the story: use 2048-bit keys, or stunnel4 or some such to re-wrap the SSL communications with a stronger key.

The KeypadLinc backlights can be completely shut off, and both their on and off levels can be customized. I have it set to shut off the backlight during the day and turn it on at night. The wall switches, however, can’t have their brightness status LED bar entirely shut off. They can be made dim, but don’t ever go away. That’s rather annoying.

Also annoying is that Insteon doesn’t make switches in the traditional toggle switch style in colors other than white. As our house had mostly black switches, I was forced into the Decora style.

Overall thoughts

This has been a great learning experience for me in a number of ways. I have only begun to tap what the system can do, and the real benefits will probably come once I get the heating and cooling into the mix. It’s quite a nice way for a geek to go, and the improvements in lighting have also been popular with everyone else in the house.

First Steps with Home Automation and LED Lighting

I’ve been thinking about home automation — automating lights, switches, thermostats, etc. — for years. Literally decades, in fact. When I was a child, my parents had a RadioShack X10 control module and one or two target devices. I think I had fun giving people a “light show” turning on or off one switch and one outlet remotely.

But I was stuck — there are a daunting number of standards for home automation these days. Zigbee, UPB, Z-Wave, Insteon, and all sorts of Wifi-enabled things that aren’t really compatible with each other (hellooooo, Nest) or have their own “ecosystem” that isn’t all that open (helloooo, Apple). Frankly I don’t think that Wifi is a great home automation protocol; its power drain completely prohibits it being used in a lot of ways.

Earlier this month, my awesome employer had our annual meeting and as part of that our technical teams had some time for anyone to talk about anything geeky. I used my time to talk about flying quadcopters, but two of my colleagues talked about home automation. I had enough to have a place to start, and was hooked.

People use these systems to do all sorts of things: intelligently turn off lights when rooms aren’t occupied, provide electronic door locks (unlockable via keypad, remote, or software), remote control lighting and heating/cooling via smartphone apps, detect water leakage, control switches with awkward wiring environments, buttons to instantly set multiple switches to certain levels for TV watching, turning off lights left on, etc. I even heard examples of monitoring a swamp cooler to make sure it is being used correctly. The possibilities are endless, and my geeky side was intrigued.

Insteon and Z-Wave

Based on what I heard from my colleagues, I decided to adopt a hybrid network consisting of Insteon and Z-Wave.

Both are reliable protocols (with ACKs and retransmit), so they work far better than X10 did. Both have all sorts of controls and sensors available (browse around on for some ideas).

Insteon is a particularly interesting system — an integrated dual-mesh network. It has both powerline and RF signaling, and most hardwared Insteon devices act as repeaters for both the wired and RF network simultaneously. Insteon packets contain a maximum hop count that is decremented after each relay, and the packets repeat in such as way that they collide and strengthen one another. There is no need to maintain routing tables or anything like that; it simply scales nicely.

This system addresses all sorts of potential complexities. It addresses the split-phase problem of powerline-only systems, but using an RF bridge. It addresses long distances and outbuildings by using the powerline signaling. I found it to work quite well.

The downside to Insteon is that all the equipment comes from one vendor: Insteon. If you don’t like their thermostat or motion sensor, you don’t have any choice.

Insteon devices can be used entirely without a central controller. Light switches can talk to each other directly, and you can even set them up so that one switch controls dozens of others, if you have enough patience to go around your house pressing tiny “set” buttons.

Enter Z-Wave. Z-Wave is RF-only, and while it is also a mesh network, it is source-routed, meaning that if you move devices around, you have to “heal” your network as all your nodes have to re-learn the path to each other. It also doesn’t have the easy distance traversal of Insteon, of course. On the other hand, hundreds of vendors make Z-Wave products, and they mostly interoperate well. Z-Wave is said to scale practically to maybe two or three dozen devices, which would have been an issue for me, buut with Insteon doing the heavy lifting and Z-Wave filling in the gaps, it’s worked out well.

Controlling it all

While both Insteon (and, to a certain extent, Z-Wave) devices can control each other, to really spread your wings, you need more centralized control. This lets you have programs that do things like “if there’s motion in the room on a weekday and it’s dark outside, then turn on a light, and turn it back off 5 minutes later.”

Insteon has several options. One, you can buy their “power line modem” (PLM). This can be hooked up to a PC to run either Insteon’s proprietary software, or something open-source like MisterHouse, written in Perl. Or you can hook it up to a controller I’ll mention in a minute. Those looking for a fairly simpe controller might get the Insteon 2242-222 Hub, which has the obligatory smartphone app and basic schedules.

For more sophisticated control, my friend recommended the ISY-994i controller. Not only does it have a lot more capable programming language (though still frustrating), it supports both Insteon and Z-Wave in an integrated box, and has a comprehensive REST API for integrating with other things. I went this route.

First step: LED lighting

I began my project by replacing my light bulbs with LEDs. I found that I could get Cree 4-Flow 60W equivs for $10 at Home Depot. They are dimmable, a key advantage over CFL, and also maintain their brightness throughout their life far better. As I wanted to install dimmer switches, I got a combination of Cree 60W bulbs, Cree TW bulbs (which have a better color spectrum coverage for more true colors), and Cree 100W equiv bulbs for places I needed more coverage. I even put in a few LED flood lights to replace my can lights.

Overall I was happy with the LEDs. They are a significant improvement over the CFLs I had been using, and use even less power to boot. I have had issues with three Cree bulbs, though: one arrived broken, and two others have had issues such as being quite dim. They have a good warranty, but it seems their QA could be better. Also, they can have a tendency to flickr when dimmed, though this plagues virtually all LED bulbs.

I had done quite a bit of research. CNET has some helpful brightness guides, and Insteon has a color temperature chart. CNET also had a nifty in-depth test of LED bulbs.

Second step: switches

Once the LED bulbs were in place, I was then able to start installing smart switches. I picked up Insteon’s basic switch, the SwitchLinc 2477D at Menard’s. This is a dimmable switch and requires a neutral wire in the box, but acts as a dual-band repeater for the system as well.

The way Insteon switches work, they can be standalone, or controllers, responders, or both in a “scene”. A scene is where multiple devices act together. You can create virtual 3-way switches in a scene, or more complicated things where different lights are turned on at different levels.

Anyhow, these switches worked out quite well. I have a few boxes where there is no neutral wire, so I had to use the Insteon SwitchLinc 2474D in them. That switch is RF-only and is supposed to have a minimum load of 20W, though they seemed to work OK — albeit with limited range and the occasional glitch — with my LEDs. There is also the relay-based SwitchLinc 2477S for use with non-dimmable lights, fans, etc. You can also get plug-in modules for controlling lamps and such.

I found the Insteon devices mostly lived up to their billing. Occasionally I could provoke a glitch by changing from dimming to brightening in rapid succession on a remote switch controlling a load on a distant one. Twice I had to power cycle an Insteon switch that got confused (rather annoying when they’re hardwared). Other than that, though, it’s been solid. From what I gather, this stuff isn’t ever quite as reliable as a 1950s mechanical switch, but at least in this price range, this is about as good as it gets these days.

Well, this post got quite long, so I will have to follow up with part 2 in a little while. I intend to write about sensors and the Z-Wave network (which didn’t work quite as easily as Insteon), as well as programming the ISY and my lessons learned along the way.