Things you DIDN’T WANT TO KNOW about Motion Detectors!

Why did I use this topic title? Well, after you read this post you’ll probably think, “You did all that minutia? Too much stuff. I didn’t need to know all that. All I need to know is do they work or not!” To those of you that feel that way, I apologize. But I think it’s cool and I wanted to share. I am not a professional researcher/scientist, but I’m definitely a very curious Nerd. Due to the Covid-19, this occupied my time. Yeah, I know . . . get a life . . . but I wanted to confirm & verify things for myself, especially before posting online in this forum.

After doing online research, I decided to conducted some experiments on my own. Here are some things I learned:

1. Ring Motions Detectors have a “Dwell-time” (reset-time) after detecting motion. From a Ring Support Center article (for Generation 1), "Motion Detectors have a built-in function called “dwell time.” Dwell time means that after a Motion Detector is tripped it will need a three-minute period in which it detects no motion in order to “reset” back to its default detection mode. This prevents the sensor from sending out multiple alerts for the same motion.”

https://support.ring.com/hc/en-us/articles/360001133103-Re-setting-Your-Motion-Detector-1st-gen-After-it-Triggers

2. The Ring Motion Detector (Generation 2) apparently has a Dwell-time too. I was unsuccessful finding any online information about the 2nd generation detectors. But my experiments found that Generation 2 has a shorter Dwell-time of under 30 seconds! (more details below)

3. Some people think it is necessary wait until the Dwell-time is finished, to successfully Arm your Ring Alarm system … and that is not correct. The answer from Ring was, “If you arm your Ring Alarm before the Motion Detector has cleared . . . the Motion Detector will be armed and will not be bypassed. Ring Alarm is smart enough to know that as you exit your home you may trigger the Motion Detector . . . After you leave your home and movement stops, the Motion Detector will clear as expected and be ready to detect movement. Any motion that is detected at that point will trigger the Alarm.”

https://community.ring.com/t5/Ring-Alarm/Motion-Detector-Question/m-p/10685#M1506

4. My experimentation Confirmed that Motion Detectors, even armed while still in the Dwell-time, ALWAYS sounded the alarm afterwards in both in “Home” or “Away” Modes. The maximum time (between tapping the “Home” Mode to the siren screaming) was 45 seconds! (more details below)

Details of my experiments with the Ring Motion Detectors (Generation 2):

My entire Ring Alarm system is comprised all of Generation 2 devices (Base station, motion detectors, keypads, etc.)

Dwell-time (in “Disarmed” Alarm Mode): I used three of my Motion Detectors. Completed 10 tests on each, for a total of 30 tests. Started timing when the Motion Detector’s LED flashed, indicating activation. Timing was stopped when the Ring App displayed the “No Motion Detected” notification. There was a lag-time, between when the LED flashed and the “Motion Detected” Notification arrived on my smartphone app. Therefore, I assume that this lag is also present when the “No Motion Detected” notification arrives too. But it was always under 2 seconds. I probably should subtract this lag, but I’m not a super geek. For me, it was too complicated to accurately measure, and determine factors that cause the lag (phone model, router, internet speed, etc.).

Recorded Dwell Time (in seconds)

Detector # Time Average Longest Period Shortest Period

#1 25.0s 30s 20s

#2 20.4s 26s 17s

#3 25.3s 31s 21s

The average of all three detectors is: 23.6 seconds. So, I believe it’s safe to say the Generation 2 Motion Detectors have an approximate 25 second dwell time.

Completed all Alarm Tests after switching Main Menu > Settings > Monitoring > and changing from “Professional-Monitoring” to “Self-Monitoring.” I wanted to avoid driving Ring employees crazy, or having the police show up!

Completed all Alarm Tests after switching Main Menu > Settings > Modes > “Home” (repeated with “Away”) > Exit Delay > 30 seconds. First, I would tap the “Home” Mode, listen for the countdown to start. Then about 15 seconds into the countdown, I began moving non-stop and visually confirmed the Motion Detector’s LED flashed. I never stopped moving throughout the entire countdown. And I still kept moving until the alarm blared. Conducted this experiment 5 times in “Home” mode, and then again 5 times in the “Away” Mode, for a total of 10 times. Every time the countdown finished, approximately 15 seconds later the alarm went off. Maximum time (from tapping “Home” Mode to the siren going off) was 45 seconds.

When measuring the Gen 2 “Dwell” time, and then doing the alarm experiment, this whole thing turned out to be quite an aerobic exercise for me!

Too much information? Well, for those that read this whole post, I hope you find it useful. ?

4 Likes

Thank you! @B-Rad :slight_smile:

Hi Boone, Thank you for the information. Its not clear to me why the siren would activate while in the Home mode during your experimentation. I was under the impression that motion sensors do not activate the siren while in Home mode. Also, if I understand correctly, in Away mode, it takes a full 15 seconds, despite continuous motion, before the siren activated after the countdown. That strikes me as excessively long. A lot can happen inside of 15 seconds. Finally, am curious if you have done any experimentation with the motion sensor employed as triggers for Alexa routines. I have 1st generation motion sensors and find that they are not responsive enough to trigger smart lights. I would be very interested to know if the 2nd generation motion sensors are any quicker.

1 Like

Hi @JFW0928 ,

Those are excellent questions! And I do appreciate your “thank you” very much. :slight_smile:

I re-read my post about the way I determined the “Dwell Time” for 2nd Generation Motion Sensors, since I wrote it months ago. Now I can see how I might not have been as clear as I meant to be. Hopefully I can answer your questions and clear things up. Before I start, let me refresh some key points to avoid creating any other new confusion.

Of the 3 available alarm modes “Disarmed”, “Home”, and “Away”, only two of them are Armed Alarm Modes capable of activating the alarm response & siren. The " Home" and " Away" Alarm Modes are the two armed modes.

You are correct that typically most people set up their " Home" Mode with all their door and window Contact sensors enabled to form a ‘protective perimeter barrier’ around them while they are home inside. And they typically set up their “Home” Mode with their Motion sensors not enabled to allow their interior movements (which are still being detected) to NOT be used to trigger the alarm response & siren. That way, as long as you remain inside (not opening an exterior door and not opening a window) you are free to roam about without a Motion Sensor triggering the alarm response & siren.

When you depart the house and everyone is Away, most people configure their “Away” Mode settings to have ALL Contact and Motion sensors enabled , thus detecting Intruders that trigger the ‘protective barrier’ and/or cause movement Motion inside (if they gained entry by breaking a window instead of opening it and thus not activating the window’s Contact sensor).

BUT, Ring designed the Modes so you can tailor both Armed Modes of “Home” and “Away” as you want. You can change your settings in each of the armed modes to have any combination of Contact or Motion sensors enabled, but you must have at least one sensor enabled.

To ** enable/disable which sensors** you prefer to have in each Armed Mode :

  • Main Menu (the 3 horizontal line icon, upper-left-corner of dashboard) > then select “Devices” > Alarm Base Station > and then select the Contact or Motion sensor > Mode Settings > and toggle whether you want this sensor to trigger or not trigger the alarm in the “Home” and/or “Away” Modes > and finish by selecting “Save” upper-right-corner.

Also the " Placement" setting is important for your sensors. Once an armed Mode is activated, the “Placement” designation you set for each sensor will determine if the alarm will immediately go off or delay (for the time you set on the Entry/Exit delay).

  • Contact Sensor “Placement” set at:
    • “Main Door”: Uses delay Entry/Exit Time settings.
    • “Secondary Door” or “Window”: No delay. Immediate.
  • Motion Sensor “Placement” set at:
    • “Entryway”: Uses delay Entry/Exit Time settings.
    • “Room”: No delay. Immediate.

To set “Placement” for each sensor:

  • Main Menu > “Devices” > Alarm Base Station > and then select the Contact or Motion sensor > select the blue “Gear” icon (upper-right-corner) > Placement > choose Placement designation > “Save” (upper-right-corner).

You set a Entry/Exit delay (most use the 30-seconds option) so you have sufficient time to arm/disarm as you exit/enter. On the entryways that you use, set Placement as “Main Door” (Contact sensors, and you can have as many “Main Doors” that you want to use, not limited to only one door). And any Motion sensors that can possibly detect movement at these entryways, should have their “Placement” set to “Entryway.”

To set Entry/Exit Delays for “Home” and “Away” Modes:

  • Main Menu (the 3 horizontal line icon, upper-left-corner of dashboard) > Settings > at your Location select “Modes” > for Delay choices, pick “Home” and/or “Away” > scroll down to Entry Delay / Exit Delay and then select > Pick your desired time delay > “Save” (upper-right-corner).

1.) You wrote, “Its not clear to me why the siren would activate while in the Home mode during your experimentation. I was under the impression that motion sensors do not activate the siren while in Home mode.

Ring allows you to tailor both Armed Modes of “Home” and “Away” to have any combination of Contact or Motion sensors enabled. Why would some people want to do that? There are many reasons, but I’ll give you a few examples:

For “Home” Mode:

  • For my “Home” Mode, I have all my Contact sensors (on my doors and windows) enabled and I also have a Motion sensor enabled which is mounted in my garage. Now I can move about freely inside my home with my ‘protected perimeter’ and also have my garage protected awaiting to detect any Intruder that could get into my garage.
  • Some people only use their armed “Home” Mode while sleeping at night. So they could sleep upstairs with all their downstairs Motion sensors enabled. Now they would have the ‘protective perimeter’ and the extra benefit of Motion sensors if an intruder breaks a downstairs window (that ‘breaking glass’ sound might not wake them from their deep sleep). Of course these people would have to stay upstairs to avoid activating the downstairs Motion sensors. There are a variety of methods to arm/disarm their “Home” mode in this configuration. For example:
    • They could use a downstairs Keypad and set a sufficient Entry/Exit Delay time to allow them to get upstairs before the ‘countdown’ finishes and the Base Station becomes armed. With proper “Placement” setting of “Entryway” on appropriate downstairs Motion sensors that they may trigger going downstairs in the morning, they could safely travel downstairs to use the downstairs keypad to disarm before the ‘countdown’ finishes.
    • They could utilize an additional upstairs Keypad or use their cellular phone (with an Entry/Exit Delay time of “Zero”) and only arm “Home” once upstairs and always disarm prior to going downstairs.

For Away Mode:

  • For my normal “Away” Mode configuration, I have all my Contact and Motion sensors enabled. Three Motion sensors are downstairs, one in the garage, and two upstairs. When my daughter visits for awhile, like for a week or two, she brings her big dog. This dog is hardly a guard dog because he loves everybody :slight_smile: LOL ! But when we want to go out and leave the dog at home, I change my “Away” setting to exclude one of the downstairs motion sensor. This way, I still have good downstairs “Intruder coverage” with her dog confined in part of the downstairs area, with 2 of the 3 sensors still enabled (without locking him in a small bathroom). While on this topic, I want to emphasize that it is not necessary to have a motion sensor in every room. With one or a few motion sensors mounted in key areas, where an intruder is most likely to go and have difficulty avoiding, will provide sufficient “break-in” protection.

So @JFW0928 , I repeated my Motion Sensor experiments 5 times in “Home” Mode and 5 times in “Away” Mode (for a total of 10 times) with the intent of showing that there was nothing special or different in either armed modes. The results were the same. Since you can configure your sensors any way you want in either arm mode, the “Home” and “Away” are just easy “label names” so you can easily remember which is the appropriate mode for when you are home or when you go away. For example, you could configure your “Home” Mode with all sensors enabled and your “Away” Mode with only Contact sensors enabled, thus resulting in reversing their roles . . . and you would need to arm “Away” while staying home and need to use “Home” when everybody leaves.

2.) You wrote, “Also, if I understand correctly, in Away mode, it takes a full 15 seconds, despite continuous motion, before the siren activated after the countdown.

Ah, you misunderstood what I wrote. First remember that all sensors are always ON (there is not a sensor OFF switch). To really “turn off” a Motion sensor you need to remove the batteries or have dead batteries in it.

When a Motion sensor initially detects triggering movement, the sensor:

  1. Always and immediately “tells” the Base Station, using Z-Wave frequency. Whether your Base Station ‘decides’ to immediately activate the siren or delay for the Entry/Exit Delay setting depends on your “Placement” setting (“Entryway” or “Room”) you used for that sensor.
  2. It begins its “Dwell-Time”, a reset period, after 'telling" movement was detected.
  3. It does not communicate to the Base Station again until the Dwell-time is over.

Why is there a Dwell-Time at all? One reason is the detector would continually be telling the Base Station “there’s movement, there’s movement, there’s movement, etc.” and your phone (if Notifications & Chirp sounds are enabled) would go off over and over and over again. The Base Station only needs to be ‘told’ once to trigger an alarm. Dwell-Time attempts to limit one Z-Wave signal per the same motion triggering event. I kept up the continual movements so that the instant the Dwell-Time finished, it would ‘see’ my movements and trigger right away.

My experiment tried to determine and find the answers to 3 things:

  1. How long is 2nd Gen Motion Sensor “Dwell-Time”?
  2. If the “Dwell-time” is still ongoing as the Alarm system finishes it ‘countdown’ and becomes armed, did the Base Station ‘by-pass’ this sensor and therefore will ignore any future Z-Wave communication from the sensor, so now that sensor can not trigger the alarm later?
  3. Are “Home” and “Away” Modes different in any way? Or are these basically just two armed modes that function the same, but just with different names/labels?

So during my experiments, I initiated the 30-second arming sequence, and wanting to insure the sensor started its Dwell-Time while the arming “countdown” was occurring, I initiated my movements (and hacked the stopwatch) 15-seconds into the ‘countdown’. So the countdown had already completed 15 seconds when I started moving, with 15 more seconds to go to arm. So when the Alarm system was completed arming the sensor was still in its Dwell-Time. And then the Dwell-time finished, it detected my continuing movement, and the alarm immediately sounded the siren (and I noted the stopwatch time). So the siren sounded about 10-15 seconds after it completed the countdown. I hope that clears up any misunderstanding.

So, I apparently found out that:

  • It’s safe to say the 2nd Generation Motion Detectors have an approximate 25 second “Dwell-Time”, much shorter than the 180-seconds for 1st Gen sensors.
  • If the Alarm system is in the process of ‘counting down’ to arming, while the Motion sensor is in the Dwell-Time reset process, the sensor is Not bypassed by the Base Station.
  • There is essentially no difference between the the “Home” or “Away” modes. It just depends on which sensors you set to be enabled to trigger the alarm.

Now during a typical departure from your house with 2nd Gen Motion Sensors, and your movement triggers it as you are getting ready to depart and arm with your 30-second Exit Delay setting, by the time the countdown is completed, the Dwell-Time already has finished and your alarm is ready when the countdown completes!

**3.) ** You wrote, “Finally, am curious if you have done any experimentation with the motion sensor employed as triggers for Alexa routines. I have 1st generation motion sensors and find that they are not responsive enough to trigger smart lights. I would be very interested to know if the 2nd generation motion sensors are any quicker.

Sorry, I do not have nor use any Alexa/Echo device, nor do I have any Smart Lights. Personally, it still kind of creeps me out having something always listening while I’m in the privacy of my home. On several other modern devices that I do own, I’ve also disabled their ability to listen, if they have that capability. Maybe in the near future, I’ll get over this creepy feeling. So I can’t really answer that question.

As for the responsiveness and quickness aspects between the 1st and 2nd Generation Alarm Motion Sensors, from what I’ve read about the 1st generation, is that the 1st is more liable to trigger off a ‘false’ perceived movement. The 2nd Gen has better algorithms and improved PIR detectors to reduce these false triggers.

Another important aspect to keep in mind is that a characteristic of Passive Infrared (PIR) sensor of the Motion Sensor is that they are most sensitive with motion across the field of view , and **least sensitive directly toward or away ** from the sensor. It is a delicate ‘balancing act’ between high reliability vs false alarms, so these Alarm motion detectors cannot act like just a simple “on/off” switch. That’s why it is important to try to optimize your detector’s mounting location to take advantage “across movement” while keeping in mind the location of any nuisance heat sources (windows, heat-ventilation, etc.).

So with 2nd Gen alarm sensors, the newer algorithms could inadvertently miss a real movement initially but it will figure it out if it is real in a few extra moments, so that might slightly delay its response. Sensors have to do their best to reliably detect an Intruder without causing false alarms, so its a difficult ‘trade-off’ to accomplish for a device.

And if you are referring to outdoor Smart Lights, the more appropriate Motion Detector sensors should be the outdoor sensors (which do not activate the alarm system and therefore more like ON/OFF switches):

https://ring.com/products/smart-lighting-motion-sensor

Thank you for your excellent questions. I hope you find this information useful. :slight_smile:

4 Likes

Mr. Boone, I apologize for taking so long to express thanks for the effort you put into answering my questions. I did not realize that the alarm modes were configurable. It makes sense that they would be. I just assumed that they were not. I also did not know the motion sensors were more sensitive to cross movement than they are to straight ahead movement. In short, your reply was very informative and very grateful for your efforts.

3 Likes

@JFW0928 wrote:

Mr. Boone, I apologize for taking so long to express thanks for the effort you put into answering my questions. I did not realize that the alarm modes were configurable. It makes sense that they would be. I just assumed that they were not. I also did not know the motion sensors were more sensitive to cross movement than they are to straight ahead movement. In short, your reply was very informative and very grateful for your efforts.

Ah, Thank you @JFW0928 for you kind words and Kudos. I’m glad to have been helpful. My pleasure! :slight_smile:

1 Like