Proximity Sensor To Start Recording


Relative noob for Physical Security systems but not IT. We need to perform the following: Start recording when a person is 6 to 8 feet away from a specific object/spot. When the person o/object is removed from the area then recording would stop. We are Ok on the VMS side for the alarm. We are having some problems finding what sensor to use. A mat would have been used but not practical in that environment. What would you suggest for a sensor with a relay that would allow us to reliably detect the presence of a person or object within an angle of 60 degrees and a radius of 5 feet or less? We would like it to be low cost (<$30) and be able to be powered by 12 VDC with a relay output.

Your suggestions are welcomed

Thanks In Advance

Why not use video analytics / VMD region detection for this? You could try built-in capabilities of the existing VMS or camera.

I'd start there to see if that was reliable enough before trying to integrate external sensors.

We have come to rely more on external/indpendent sensors. An example is the motion detection of cameras: Too often tricky and a source of many false (or missed) alarms a PIR OTOH gives, in our experience, more consistent results. We would like to rely on similar.

We have come to rely more on external/indpendent sensors.

I think you are drawing conclusions from bad data and also possibly setting an unrealistic budget ($30).

When you say "person or object", do you mean non-person objects (robots?) might suddenly appear in this area and need to be detected? What is the actual problem you are trying to solve, don't just say "detect a person", but explain *why* you want to detect the person. If you want to detect more than just a person, please give some examples of the non-person objects because some things like PIR's might be completely wrong or completely appropriate, depending on other info. Why was the mat not practical? Would beam-break sensors be practical? Would you rather err on the side of missing some recordings, or possibly recording too often (false alarms in essence).

What is going to do the recording? An existing system, or do you need/want a camera with some kind of on-board SD card recording?


It is for kiosk. There is a lot of Traffic (motio) within the field of view of the Kiosks cameras. Thus we don'tthink Motion Detection would be the appropriate solution. We need recording to reliably begin only when someone comes close to or is at the Kiosk. The VMS willbe set for 3 secs of Pre-recording before the actual event/alarm of detection by the proximity sensor. A proximity sensor seems to be the Key. When a person or robots :) gets to within 6 feet of the kiosk. Recording starts. The person moves away, recording stops with a post event recording of 3 secs.

As for the $30 budget it seems indeed to be low. Our research shows $75~$120 to be the range for a microwave-type proximity detector. We still need your input and experience with such a solution.


For arguments sake why couldn't you use something like this?


Not sure We could use a PIR since there is traffic around the kiosk. We need recording to start only when a person is coming to the kiosk. A mat could have been a solution but wasn'tretain by the customer for logistics reasons. We believe thus a proximity solution is the best thus our asking for suggestions on this remarkable forum.

Not sure We could use a PIR since there is traffic around the kiosk. We need recording to start only when a person is coming to the kiosk.

You need to clarify this to get a better suggestion. Your OP states 6-8 ft as the distance to start recording, then later says less than 5 ft radius.

You say only when a person 'is coming' to the kiosk, so by this do you mean that someone just passing by the kiosk, but not toward the kiosk, at a distance of 3 ft should not trigger it?

What is your acceptable false alarm rate?

PIR with shields (or you can use tape, but the shields look cleaner) over the kiosk to narrow its viewing angle. If you can set it up overhead at approximately 8ft, I would use a REX as those come with small plastic shields. I guess you could use a beam detector if its mounting fits into the application and there is a need for that precision.

What is the purpose of the camera recording? Is it to watch for theft/vandalism or are they looking for a way to count how many times a day people interact with the kiosk?


I am repeating there is a substantial of people traffic around the Kiosk. This will fool Motion Detection activated recordings. I believe Proximity Sensors are the best solution. We are however unfamiliar with these. I have found a company that sells Ultra-sound based proximity sensor. The price is about $110 per sensor. We will test it and report to you

We thank you for your great replies. They were though-provoking and extremely informative. One more reason why I brought this to this collective

Kudus People!!

You might consider a pressure mat alarm sensor. We have used these to trip door locks on the secure side of the door in a high traffic area when we didn't want background traffic to constantly trip motion sensors. Just a quick google search, but here's an example:

Alarm Controls recently introduced a request-to-exit motion detector called the SREX-100 that is supposed to have tightly controlled coverage pattern and adjustable range. I haven't personally tested one, but it sounds like it might work in your application.

Von Duprin used to sell a request-to-exit detector that used a Polaroid Range Finder as its detection device. You could precisely set the detection range down to 1/4" increments and it wouldn't detect anything closer or farther away - a remarkably accurate device. Unfortunately the device emitted a constant "ticking" sound in the ultrasonic range that some people could hear and find annoying. (I'm sure that dogs loved it too...). It's no longer sold and I have yet to find a motion detector whose detection pattern can be so well controlled.

Google Long range RFID Tags and receivers

You will easily get up to ~ 100 feet range

I am repeating there is a substantial of people traffic around the Kiosk. This will fool Motion Detection activated recordings.

So then what's with the whole 'start recording when 6-8 feet away' requirement?

Does the person have to interact (touch) the kiosk to use it?

If so why not just use a capacitive sensor on the screen bezel? Or a short range robotic IR sensor? With 30 second pre/post record?

Are you recording the interaction for business intellgence or for asset protection?

I'd be glad to suggest actual components if you think it's worth exploring.

If you have not chosen or installed any system yet, you could use a Mobotox camera and use onboard event logic using VM windows. Meaning VM1 needs to trip followed up by VM2 and this would allow for directional based event recording. This is proven to work and very reliable in kiosks, Not to mention you get the entire solution built into a single device. In addition Mobotix is slated to release our own Proximity detector should you wish to keep it to a single provider. Just a thought.