Proximity Sensor (People Detector)

David_AVD

David_AVD

Grandpa Elf
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We've talked (on and off) over the last year about interactive displays for Christmas and Halloween. I'm still keen to find reliable ways to detect people and trigger animations, etc.

I think we need to sense people in the 500mm to 1500mm range. Proportional (range) sensing would be good too, as you could change / increase the effect as people get closer. Breaking a beam of IR light is easy, but requires alignment and you can't always access both sides of the detection area.

I have found a couple of sensors that may be suitable. One is a narrow view PIR sensor that is in quite a small package, but purely on/off sensing. The other is a proportional reflective IR sensor that looks for an IR beam bounced back from an object. Both are on order from O/S and I'll test them once they arrive.

I have tried an ultrasonic range sensor (robotics type) that works quite well, but the transducer is quite open to dust and water ingress so wouldn't last long outside.

Does anyone have any other ideas? Maybe someone here works with industrial machinery and knows of a low cost solution?
 
David

I had a guy at work describe something that may fit this precisely, i'll catch up with him and see if i can get some part numbers... may be something you already know but won;t hurt to find out.

Phil
 
I have something similar to this, albeit designed for a static display. Its a simple motion detector, not unlike those on secrity lights, but sold seperately. Then i've simply cut an extension cord in half and put the sensor in the middle. Then in the end, i plig what ever light i want into it. The semsor just has to be mounted in the right spot, adjusted so the sensitivity is right up close, and, voila, lights on when ppl get close. However, im not sure how you would adapt this to sense people at different ranges and do something different for that distance.
Hope that helps anyone. Ill be lookinf forward to see how ppl make the lights change for various distance. Heres a thought, how about pressure plates :p when some one stands on the correct spot, theres a trigger under foot which tirns lights on or off. Just throwing ideas around now.

Luke
 
Kinda not the same but been using my CCTV system software to achieve this. Built in function of the alarm system software, I just count the "alarm events" each night, gets me close enough for braving rights :))
 
Reversing/parking sensors are sort of around the range you're talking about Dave.
 
AAH said:
Reversing/parking sensors are sort of around the range you're talking about Dave.
Click to expand...

Hmmm... I like that Alan. Those sensor heads are obviously weatherproof and there may be a cheap after market version available from China.
 
I remember my son getting a warning sensor alarm from a Mcdonalds happy meal that if you walked past it it would send of an alarm wonder if something can be designed using these cheap parts
 
David_AVD said:
AAH said:
Reversing/parking sensors are sort of around the range you're talking about Dave.
Click to expand...

Hmmm... I like that Alan. Those sensor heads are obviously weatherproof and there may be a cheap after market version available from China.
Click to expand...

OK.I have one of these reverse kits in the garage I can donate.
 
David, I use PIRs that are designed for outdoor floodlights. You can purchase the PIRs alone for about $15 - $20 US.
My display uses 2 of these, one to activate an audioanimatronic Santa that invites folks to drive into a parking area, where a second PIR then sends out an X-10 signal that turns on all of the various outlets throughout the display.
If you adjust their sensitivity properly they are very reliable, and don't false with snow or rain (although they occasionally do on a cold day when a warm front is coming through, and they sense warm winds).
I have used them in my display for well over 20 years without issue...
Greg
 
I had thought about conventional PIRs, but their range is much wider and deeper than I want. I am envisaging much finer detection zones; less than a metre wide and 1-2 metres deep.

The narrow PIR (Panasonic sensor) and the reflective IR are looking good, while the ultrasonic may be able to be tuned to suit. I'll know once the samples arrive and I have a play.

I actually have a commercial application for all this in mind, but wanted to see if there was a easy low cost solution that could be translated to the DIY Christmas side of things.
 
David_AVD said:
I had thought about conventional PIRs, but their range is much wider and deeper than I want. I am envisaging much finer detection zones; less than a metre wide and 1-2 metres deep.

The narrow PIR (Panasonic sensor) and the reflective IR are looking good, while the ultrasonic may be able to be tuned to suit. I'll know once the samples arrive and I have a play.

I actually have a commercial application for all this in mind, but wanted to see if there was a easy low cost solution that could be translated to the DIY Christmas side of things.
Click to expand...

Understood. The PIRs however can be adjusted for a much smaller range.
I would avoid ultrasonics which tend to false a lot. Been there done that!
Outdoors the beam/reflectors also have a higher incidence of falsing (rain, insects, etc).

I should mention the PIRs I use all have double hit technology (requiring dual instances of movement to trigger), again which helps reduce falsing.

Greg
 
Just tested one of the Panasonic miniature PIR sensors I received today. It's very sensitive and has a 91 x 91 degree sensing range which is surprisingly hard to restrict. I might try one of the 38 x 22 degree versions at some stage.
 
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