It's time to scrounge around the box of unused X10 devices for anything useful while my home automation setup still supports X10 hardware. I found a motion sensor (ActiveEye model MS16A). There is a good location for it at the bottom of the stairs leading to the landing. If I could get it to work, it could turn on lights to reduce fumbling with the key and lock at the front door when it is dark.
What the sensor will do
The sensor operates as follows. Its address is set to the same address as an X10 switch. While the sensor detects motion, it sends wireless "on" messages. The first of these messages switches the light on, the following do nothing (except clutter the airwave and power line) because the switch is already on. Once the sensor no longer detects motion, it waits for a programmable period of time and then sends a wireless "off" message which will shut the light off.
What the sensor will not do
The mode of operation described above would not work in my house for three reasons:
- I want two lamps, controlled by X10 modules with different addresses, to be powered when motion is detected.
- If a light were already on before the sensor detects someone outside then it must not be turned off after motion is no longer detected because, presumably, that light was serving a purpose.
- The lamp modules cannot be reached by the CM19A wireless transceiver. The two wireless receivers (an RR501 and a TM751) with which it can communication are, as luck would have it, both connected on the same phase of the house wiring while the lamp modules are connected on the the opposite phase.
Setting up the sensor
It turns out that when you change the batteries, the sensor will return to the default address: A1. After loosing the settings a few times because of this, I gave up and decided to accept the default. Hopefully, neighbours will not be using the A house code soon.
I setup my sensor to report movements day and night and to report dusk and dawn explicitly. By default the latter is done with an on and off message to an address with the same house code as the motion sensor but with a unit code equal to the successor of the motion sensor. This means the sensor will be sending "A2 on" and "A2 off" messages to report on the light level.
I did not change the default behaviour for the off message. I can use the adjustment screw on the sensor itself to dial in the delay. But it does not really matter, the off message will be ignored; the software will take care of turning off the lights.
Summarizing, I have setup the MS16A so that it looks like two sensors:
- "A1 on" : motion has been detected and
- "A1 off" : no motion detected in the last xx minutes (not used)
- "A2 on" : it is dark
- "A2 off" : is is light outside.
Adding sensor devices to Domoticz
Adding the motion sensor is as simple as adding a switch. Place it close
enough to the CM19A (or CM15A) rf receiver. There is a minimum delay of
one minute between messages that the sensor sends out, so wait a minute or
so to let the sensor calm down. Click on the
tab, and then on the button.
When prompted to activate the remote, wave your hand over the sensor.
Then fill in the name
and change the switch type in the pop up dialogue window:
Adding the dusk sensor is somewhat more complicated because it is harder
to trigger it on demand. Perhaps you could try putting the sensor under a
blanket and using a flashlight to simulate the sun. What I did was to open
an ssh session on the Raspberry Pi, and then I
nc localhost 1099) and
prepared to send the on command: (
rf a2 on). Back on the
Switches tab, I clicked on the
button and then quickly
pressed the Enter key in the ssh terminal make the
Mochad bridge send the
rf a2 on command to
Domoticz. Much as above, you will have to enter a
name and change the switch type to
A First Dysfunctional Lua Script
Following script naming convention, I saved the following script
in the file
The great thing about the
On FOR 10 minutes command is that
once the 10 minutes are passed, the switch is returned to its original
on/off status. If the lamp was already on, it will remain on and will not
be switched off.
A Second Dysfunctional Lua Script
I tested the script by manually using
netcat to talk to
The lights went on and off as expected; lights turned before I sent the fake sensor message remained on after the 10 minute delay. I also concluded that 10 minutes is a long time to walk 5 steps and open a door. I wanted to change the ON_TIME but also wanted flexibility to experiment. Rather than editing the script file each time I wanted to try a new value, I decided to create a user variable so that the delay could be adjusted within the Domoticz web interface. This can be done with just a little bit of tweaking.
First create the user variable. Click on the Setup
tab, then on the More Options menu, then
on the User variables menu item. Continue
on to Edit variable by filling in the
variable name, variable type and its initial value. Complete the
operation by clicking on the button.
To change the value of on delay later on, repeat the three steps to get back to the Edit variable screen, but now click on the line corresponding to the variable in the table. The variable name, type and value fields will be filled. Adjust the variable value to the desired number of minutes to wait before turning off the lamps and click on the button.
Adjust the script; the constant
ON_TIME is no longer set but it
is replace with a variable
on_time set to equal the value of
the user variable Sensor_Delay created in the previous step.
A Third Working Lua Script
The script worked well when tested manually, but it took only one field test at night to see that it did not work. Typically, the sensor will send more than one on message. That makes the script fire more than once. The second time it fires, the lamps are both on, and when the delay passes, they will remain on no matter what the initial state was before the first on message from the sensor.
One possible solution is to setup a user integer variable, say
Motion_Detected with an initial value of 0 (= false).
When processing an on message from the sensor, the script would begin with
a test: if
Motion_Detected is false (= 0) then it sets
it true (= 1) and continues as before, turning on the lamps. If
Motion_Detected had been found to be true (=1), then the
script ends doing noting because signals that the lamps are already on.
Then there would be the need to write a time script (script_time_xxx.lua)
which is executed once every minute. If it finds
Motion_Detected is true, then it calculates the time elapsed
since it was last accessed. If that time measured in minutes is longer
than the value of the variable
DELAY_VAR then it sets
Motion_Detected is false.
I chose another approach. I created an invisible virtual sensor (type
$SensorState in a new Dummy Hardware called
Virtual. we have already done this in setting up
Heyu, so here is a quick outline of the steps.
- Click on Setup tab.
- Click on on the Hardware menu choice.
- Fill in the fields
Dummy (Does nothing...
- Click on the button.
- Click on the
- Name the sensor
$SensorStateand change its type to switch. Starting the name with a dollar sign '$' hides that switch which will be visible only in the devices list
- Click on the OK button.
DELAY_VARminutes at the same time it turns on the other lamps. Domoticz will take care of turning off the switch. And the script can test the switch's state at the beginning and do nothing if it is already on.
Third time lucky? Hopefully this will work.The script does what I want. Only trouble is that I reach the door before the lights turn on. There is probably a delay in the sensor itself at it "debounces" the signal before sending its first on message. And then X10 hardware is not very fast. Short of learning to walk more slowly, the easiest solution may just be to move the sensor further back from the front door. I will investigate later on when its batteries are weaker, and the temperature has dropped even more. That way conditions will be at their worst and I will be able to see the limits of the rf link.