Sensitivity settings - exact meaning?

Hi,
I have had a look but not very satisfied with the responses, at least not the ones I found… so…
I would like to know what exactly the sensitivity settings are doing.
Does 10 mean that any pixel motion (heat?) triggers a recording and 1 mean that say 100 pixels change triggers a recording?
You can see that my question is naive, but I would like to understand exactly how the sensitivity setting works.
I am seeing no difference between 3 and 5, so I’d like to understand what is the difference between the 2 values.
And rather than trial and error it would be good to understand the technology, or if it is proprietary, at least enough to say that if I want to stop small movements, but capture big movements what I should be aiming for…
Thanks.

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Blink cameras have a passive infrared motion sensor. So it’s not based on changes to pixels in the video feed. I think most of us had to go with trial and error to find a sensitivity setting that works well; there’s always a tradeoff between false positives and negatives though. Perhaps someone from Blink can provide a more quantitative description of the sensitivity settings, but I haven’t really heard one so far.

This article has a nice explanation of how PIR motion sensors work.

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Thanks Mark.
I’m kind of happy with trial and error, but it seems a shame that Blink don’t have some better guidance.
For example, I have a Ring doorbell, which if we ignore the zoning control, it also has a sensitivity control which they call Smart something-or-other and they described how the sensitivity varies with the setting and I was hoping for a bit more from Blink.
Thanks again.

Hi @imcaufieldholt,

Unfortunately, PIR sensor have many factors which makes it hard to give a clear set of rules. It is affected by things such as ambient heat and distance of the motion that you want to detect. We find that testing with actual motion is the best way for customers to get a clearer picture of how to setup the camera.

That said, for best PIR results, the camera should be placed such that the motion goes across the field of view (right to left or left to right).

-Julian

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Yeah I hear you.

Good luck, although FWIW I’ve used a few other PIR motion sensors with my SmartThings system, and the ones with adjustable sensitivity settings don’t typically provide a very detailed explanation for what each value means.

I wish there was a simple scale here. Sensitivity setting of three means approximately how many feet will be detected… etc. It really would solve a lot of these issues. @nick_at_blink - food for thought

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@DPChristman, I think what @julian_at_blink explained sums it up well. There are too many local variables that they can’t possibly take into account. Wish all you want, but you can’t really argue with physics :wink:

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Thank you. I have had more of a play now and think I have the sensitivity set about right to ignore shadows moving etc.
The one thing that I did learn was the short range of PIRs.
I was hoping to catch movement across the garden about 100 feet away! I now know that the active distance is about 20ft…
So for people who want the camera to be triggered further away (as the video still records movement, it just needs to be told to wake up), what is a good solution.
What I would love is for the camera to cover the entire garden, but to wake up if there is movement at the far end. I could put a PIR at the far end of the garden, but I would need a repeater for the wifi signal, so that I could set up an IFTTT action. Even overlapping cameras would need a repeater to get a good wifi signal. Hmmm, I;ll have to have a little thing about this.

Mine are definitely picking up well in excess of 20ft, but I guess it is a combination of position, elevation, etc.

Hey Julian… How about simply explaining the “scale?” What factors vary from “1” to “9?”

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Start with Google . . . “How is sensor sensitivity measured?
The sensitivity is then defined as the ratio between the output signal and measured property. For example, if a sensor measures temperature and has a voltage output, the sensitivity is a constant with the units [V/K]. The sensitivity is the slope of the transfer function”.

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Marvellous explantion, i was left even more confused until you gave it to us straight, its such a brill camera with an annoyingly restrictive yet pleasantly simple app, you feel sure you can get it to behave how you’d like, but during that process you realise the sensitivity settings dont appear to follow typical values and can be a little thrown off by that…do you box product up for return? do you persevere with it? and/or have you overlooked something glaringly obvious? - its nice to know it isnt the latter