pulsor sensors

[signal15]

The house I moved into 2 months ago has two pulsor sensors mounted to some floor joists with wires hanging near the security panel.  They had an ADT system in here, but they weren't hooked up to it.  I now have an Elk M1G.  
 
1. Do I need a special box or something to be able to use these?
2. Is there a way to discern the weight of the person stepping on it?  My wife weighs about half of what I do, and it would be kind of cool to do some automation based on who trips them.

 

[jpmargis]

1. Yes, you need a Pulsor Processor.
2. Yes, you need two sets of Pulsor Sensors and two Pulsor Processors set to different sensitivity levels.

 

[dgage]

I thought about putting a few pulsor sensors on the stairs to determine people going up or down the stairs. Pretty cool technology.

 

[CJW-PIC]

Could some one please provide a link for the Pulsor Sensor / Processors
Thanks in advance

 

[dgage]

http://www.sureaction.com/homealarmstresssensors.html

 

[RAL]

Automated Outlet carries the Sure Action pulsor sensors and processors.
 
The sensors are strain gauges that vary in resistance as they flex with the surface they are attached to.
 
The processor detects changes in resistance and signals the event through a Form C relay output.  The sensitivity can be adjusted so that you don't get false triggers from light loads, such as a pet, or you could use 2 zones/processors and two sensors to tell the difference between a lighter person vs a heavier person.
 
The processor won't tell you if someone is standing still in one spot.  Only that the load changed when a person stepped into the protected area.

 

[signal15]

The Elk can monitor voltage on a zone.  Since these sensors vary the resistance with the level of strain on them, I wonder if it would be possible to use the Elk as the processor instead of buying one.

 

[BraveSirRobbin]

The Elk can monitor voltage on a zone.  Since these sensors vary the resistance with the level of strain on them, I wonder if it would be possible to use the Elk as the processor instead of buying one.

I know nothing about these sensors, but offer these cautions:
 
1. it might not be a straight DC level
2. the Elk might not be fast enough to detect a quick change in signal
3. the strain gauge board may do some additional processing or analysis on the signal before providing the final output

 

[jpmargis]

:hesaid:
 
But, I guess you can try.  You won't hurt anything.  The trick will be biasing the sensors close to the ELK M1 switching threshold, but not so close that you get false triggers.

 

[RAL]

The resistance of the Pulsor sensors is nominally 1,000 ohms.  But one sensor can vary from another sensor by 20% or more.   So you won't find a single trigger threshold for the ELK that will work for all Pulsors..  
 
When I've flexed the sensor by hand, I saw the resistance changing by hundreds of ohms.  But I suspect I was flexing it far more than it actually flexes when mounted on a floor joist.  My guess is that it only changes by a few 10's of ohms when someone steps on the floor.
 
Also,I believe the pulsor processor ignores slowly changing resistance values from the sensors, and triggers only on sudden changes that exceed the set point.  Sure Action says the Pulsor will not trigger when used on a roof due to snow loads (a slow change in weight), but will trigger from someone walking on the roof.  That seems like a nice feature to me since it means that if I leave a heavy suitcase sitting in my hallway where I have one mounted under the floor, I don't need to worry about a false trigger when my cat walks by.

 

[ano]

The resistance of the Pulsor sensors is nominally 1,000 ohms.  But one sensor can vary from another sensor by 20% or more.   So you won't find a single trigger threshold for the ELK that will work for all Pulsors..  
 
When I've flexed the sensor by hand, I saw the resistance changing by hundreds of ohms.  But I suspect I was flexing it far more than it actually flexes when mounted on a floor joist.  My guess is that it only changes by a few 10's of ohms when someone steps on the floor.
 
Also,I believe the pulsor processor ignores slowly changing resistance values from the sensors, and triggers only on sudden changes that exceed the set point.  Sure Action says the Pulsor will not trigger when used on a roof due to snow loads (a slow change in weight), but will trigger from someone walking on the roof.  That seems like a nice feature to me since it means that if I leave a heavy suitcase sitting in my hallway where I have one mounted under the floor, I don't need to worry about a false trigger when my cat walks by.

Its gets even worse than that. I've had a long phone call with the creator of these sensors. Smart guy.
 
Not only do the sensors vary widely from one to the next, they are also VERY temperature sensitive.  The sensor resistance varies widely with temperature.  I've even tried two of them to see if they react to temp. changes the same way, and they don't.  So the ONLY valid indication they give you is a quickly changing resistance, which is what their sensor detectors look for.

 

[Del91574]

These were very common in my section of the country for a lot of reasons and applications. There used to be a few manufacturers.

The key is adjustment...you can set them to ignore a 100# dog but alarm on a 120# person....the only variable is how much time you want to spend adjusting them, contrary to what was posted, you can do this with a single pulsor and analyzer.
 
We've used them in locations we couldn't get a door contact wired (custom house with stanless steel doors and jambs!) and also locations where PI motions wouldn't or couldn't be used effectively. Same went for some HA applications, but usually the labor and device cost is prohibitive to most. That said, they work awesome on stairs and decks, like marinas and the like.