Rooftop Motion Sensing System

herding_cats

herding_cats

Senior Member
Location
Kansas
Occupation
Mechanical Engineer
I was looking for any and all input on the new system we developed for rooftop security. Given the recent events of rooftop shooters, we came up with this wireless system for commercial / campus buildings.

The system is isolated from existing alarms that are disabled during the daytime.
We are powering the cameras from existing HVAC, stepping down 240/208, 277 etc to 24vac, then to USB 3vdc.



Thanks in advance. PDF data sheet attached here.
 

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  • wireless motion sensing.pdf
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Yes. It is specifically designed to prevent false trips. It has a wide range of settings for object size and sensitivity.

We think there is a huge market for this, and it does not need to integrate into existing building alarms. The problem with existing alarms is they are disarmed during the day, operating hours. This monitors 24/7. A lot of alarm companies I think would have a difficult time competing with us because they would need to hardwire the motion sensors to their existing system . Expensive and time consuming. Drilling holes in the building, etc.
 
On the rooftop at UVU where Charlie Kirk was shot from, there are about a dozen different HAVC units that would have immediately picked up motion. Charlie Kirk would still be alive today if this system was in place there. It would have notified the exact location of the sensors.
 
Roof hatch contacts can be set to alarm even if the rest of the system is disarmed, just like a tamper input, but that doesn’t cover somebody using a ladder or another close building to access the roof. Does it have a built in camera to verify a positive alarm? After a couple of false alarms (really unavoidable with any system) maintenance or a manager would probably ignore it because they don’t want check the roof.
 
Yes we thought of all of this, realizing the roof hatch and coming in from the outside, from another building. With the right placement, sensitivity settings we are pretty sure we can get it right. A lot of police/campus security folks are being equipped with small drones. Really quick way to see if someone is up there. Our system is not a camera. Motion detection only. The idea was to keep it cost effective and still provide this level of security. It's priced out to be about $250 per motion sensor installed. That includes the Ethernet hub.

We have spoken with a lot of people about their campus, buildings, etc. Rooftop security has widely been forgotten about until recently.
 
herding_cats said:
I was looking for any and all input on the new system we developed for rooftop security. Given the recent events of rooftop shooters, we came up with this wireless system for commercial / campus buildings.

The system is isolated from existing alarms that are disabled during the daytime.
We are powering the cameras from existing HVAC, stepping down 240/208, 277 etc to 24vac, then to USB 3vdc.



Thanks in advance. PDF data sheet attached here.
Click to expand...
Thanks for sharing the details and the PDF. The system sounds well thought out, especially isolating it from existing alarms and using existing HVAC power for efficiency. A few things to keep in mind: ensure stable voltage conversion to avoid affecting the cameras, test wireless signal strength in areas with potential interference, and consider backup power if the HVAC system shuts down. Overall, it looks promising and practical for commercial or campus rooftops.
 
cixov said:
Thanks for sharing the details and the PDF. The system sounds well thought out, especially isolating it from existing alarms and using existing HVAC power for efficiency. A few things to keep in mind: ensure stable voltage conversion to avoid affecting the cameras, test wireless signal strength in areas with potential interference, and consider backup power if the HVAC system shuts down. Overall, it looks promising and practical for commercial or campus rooftops.
Click to expand...
Even though the op originally said cameras, later said motion only. I think adding a sd card and camera would be a good addition to keep it cheap, and provide evidence, if needed.
 
I got some decent feedback from a security systems guy on Reddit. The rooftop security is more “event” based. Like in Butler PA and at UVU. The system might be better purposes as a temporary set up and taken down after the event. Like the motion sensors would be on small portable tripods with cellular service hub for alerts. Set these up in strategic spots on rooftops and take them off after the event.
 
I would think a regular $500 NVR surveillance camera type system could also be used for this. These have the ability to detect motion based on how many pixels change. It is designed to show live video and store it. They are typically wifi based and are setup to allow phone access. My house camera system works this way, but I don't use phone access or its notification features. I get false alarms from trees and bushes that blow in the wind, but on a rooftop you shouldn't have this issue. It also has a masking feature so I can mask out most of the bushes but keep the walking paths and driveway monitored. Only other thing that will trip it is the steam from my furnace exhaust (a 95% condensing furnace that vents through a PVC pipe) that wafts across the front porch. The cloud of vapor triggers motion video recording on cold mornings. It has also happened occasionally with morning fog banks wafting in -- the camera image looks like you are in a huge rain storm when the fog droplets are very close to the camera lens.

So I'm not sure what technology the motion detector is using -- ultrasonic, video, or what. They can all give false positives under certain conditions. The plus with a camera based system, or one employing camera plus a different type or multiple types of motion sensing, is if you can access them via a phone app you can quickly see what the intruder is -- a person, a large bird or rat, something loose on the building blowing in the wind, or a fog cloud.

A friend also has a NVR system on his house and his phone is dinging every 5 minutes with motion notifications. He needs to go through and turn the sensitivity down on his...

Final thought would be if this is deployed and left long term, you need a way to deal with service people. Either someone is going to get an alarm when there is a legit person on the roof, or there needs to be a way to turn it off or notify someone before they enter the roof.
 
I was just going to mention ^^^. Modern IP cams have this covered like a jimmy hat. The modern AI easily does object ID for false triggers, and a host of other virtual fencing, making this easily the right tech for the job. The other perc is you will actually get video, not just an alarm trip. If you are not familiar, get up to speed. Virtual trip wire is extremely handy.
 
herding_cats said:
The problem with existing alarms is they are disarmed during the day, operating hours.
Click to expand...
The good thing about integrating with existing alarms is they won't be forgotten over time.
Nobody will delete the app, forget the pay the bill, forget what the system is or where it is. The rooftop system can be set as a trigger always zone: typical alarms have that for roof hatches and emergency only doors.
 
The best advice I received on this concept was to build it as a temporary set up, and take down for rooftop motion detection using cellular internet. The shootings are "event" based. A security team could use small tripods and set these up in strategic places, on roofs, in between buildings, in places people are not supposed to be. Then take them down after the "event".
 
herding_cats said:
The best advice I received on this concept was to build it as a temporary set up, and take down for rooftop motion detection using cellular internet. The shootings are "event" based. A security team could use small tripods and set these up in strategic places, on roofs, in between buildings, in places people are not supposed to be. Then take them down after the "event".
Click to expand...
Sorry, I just can't agree with any type of basic motion sensing when modern tech prevails here. This is not a matter of "needing a solution", it't a matter of getting parties to understand, appreciate, and accept the cost burden of deployment! Seriously, if I put a $250 camera in your hand, you would be shocked! AND it's not just a motion sensor, it's all of that and more!

And why would you even do that as a temporary? Like even without an "event", do you really EVER want people around the HVAC equipment when not authorized? Thieves? Jumpers? That should be a permanent deployment.
 
fastline said:
Sorry, I just can't agree with any type of basic motion sensing when modern tech prevails here. This is not a matter of "needing a solution", it't a matter of getting parties to understand, appreciate, and accept the cost burden of deployment! Seriously, if I put a $250 camera in your hand, you would be shocked! AND it's not just a motion sensor, it's all of that and more!

And why would you even do that as a temporary? Like even without an "event", do you really EVER want people around the HVAC equipment when not authorized? Thieves? Jumpers? That should be a permanent deployment.
Click to expand...
You would provide both, event based as temporary, and motion or cameras set in place all the time. I have spent years doing diagnostics and repair on RTUs. Being so I have been on more rooftops than most of the public. Because of that I felt I needed to contribute something after 2 shootings from rooftops this last year, maybe more...
 
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