Where to place a motion sensor?

[thatdecade]

I'm trying to do something like modern soda vending machines.  The machine is dark until you walk past it, then the machine 'wakes' up to catch your attention.



I bought this light switch replacement at my hardware store and put it in electrical box so it was connected to a spike strip.  It works great, I laid it next to my arcade and the florescent, ccfl, and monitor all come on when I walk even close.  Max time was 2 hours, so I set it to that.

My problem is I can't find a good place to put it where it's not an eye soar.  Because it works with infrared, for it to see you, you would also see it and it works best at waist height or higher.
I haven't started designing my bezel (besides a piece of plexiglass sitting in the closet).  Does anyone have any ideas how I could incorporate it into that? or a better idea for somewhere else?

I don't know where it is on soda machines, but they did a good job hiding it.

[weisshaupt]

You m,ay want to remove the casing...


That one looks like it has a sender and receiver. Without the casing you would need 2 holes... I would also mounting it under the CP if it has an overhang... that way you only see it when you get down under the machine.....


Also some Plastics etc may be invisible to the IR but opaque to the eye.. If you get one of those (over even a smoked glass or plexi)  it would probably do a lot to hide the sensor, or at least make it a heck of a lot less obvious...

[mountain]

Great idea. I would think that if you mounted it under the control panel faciing forward and down at a 45 degree angle, it would sense the lower part of your body as you walked by. This will allow you to hide it completely.

[thatdecade]

Sorry, my cp and bottom cabinet are flush.  I have a black curtain down there, but it blocks the IR.  Either that or legs aren't hot enough.
I also tried my best to disassemble it, but decided I couldn't do it without breaking it.  Got the cover off, but the front plate is riveted to the circuit board.

You've got me thinking of opaque materials though.  I don't know if I want to shell out the cash for custom glass, but I do know how to frost glass/plexi.  You just brush the stuff on and let it dry.
You think it would look better 100% frosted or just the portion for the sensor? or maybe frosted 100% and paint over black the frosted section away from the sensor.  Keeping a constant texture.

 

Biggest problem I'm seeing after playing with it is that the sensor needs nearly a 180 degree field of view.  If I just make a hole so it can see straight forward, it is much less sensitive.

Here's an idea, let me know your thoughts. IR filters can be found inexpensively as developed unexposed camera film  (blocks visible, allows ir).  I could use it like pin stripes in my design and place the sensor in any of the areas.  Various widths would be available; 35mm, 120mm...



I am also ditching the monitor being powered by it.  I reset the time to only stay on a few seconds to test and it can't detect a person standing so close in front of it after the initial detection.  Doesn't matter how much you move, you're all it can see and there is no contrast.  I also worry that when I switch from my current crt to an lcd monitor, the lcd monitor won't turn on when power is removed and restored.
My idea now is to plug a dc adapter into the spike strip, run that up to an opticoupler and use that as an input to the keyboard encoder, bringing the computer out of power save.  It would be an unused key, but I worry about the bios or windows complaining that a key is being held down.  I'll have to give it some more thought.

[vertygo]

Not sure why, but I have vision of that red "eye" from 2001 ? 2010 ? HAL the computer.  Instead of hiding the sensor, make it really really obvious

Just my 2 cents.

[DaOld Man]

I dont think that sensor will work right if you remove the lens. That Fresnel lens is made to focus the infrared onto the sensor.
I put together a Game cam (wildlife game not mame) for a friend once.
I tried removing the lens from a sensor similar to that, it didnt work, but it might still work up close, I cant remember. Game cams are set for 10-30 feet detection.
I like the idea of a Hal type attachment.

[weisshaupt]

The HAL attachment idea is a good one - i used the same Idea when I was doing my modular panels and decided to make the seams between the panels obvious rather than try to hide them... if you can't hide it acting like you wanted it that way is the next best thing.

I still think a smoked plexi or glass may do the trick.. no need to go custom - Lots of PLastic and glass places carry such stuff in stock and you will only need a remnant of something they already cut up.. You may pick up the piece you need for a song.

You can also make a bigger hole, or route out some material round the hole in increase the range/detection ability.


However, I do think  DA Old MAn is right about the fresnel lens, you would need to leave that on..

Looks like it experimentation time with different materials :>)

[thatdecade]

I finished this in June, but didn't get around to writing anything up till now.  I ended up placing it on the floor angled up slightly.  I keep a table on that side of the cabinet so the motion sensor is out of sight.

Power is controlled by the PC screensaver.  Motion sensor holds down a keyboard key for a few seconds when triggered.  This brings the PC out of screensaver and turns on the monitor, lights, and sound.  If no more motion is seen and no button on the control panel is pressed after 10 minutes, screensaver activates and everything turns back off.

Notes about my power control circuits are on this page.
http://www.westaby.net/arcadeRevisted.html

[RandyT]

Cool concept. 

BTW, if anyone is still interested in a confirmation of one of the earlier suggestions, that dark smoke plexi is virtually invisible to IR.  Years ago when I first started advocating it's use in Arcade machines to hide the monitor orientation and increase contrast, I was also using a TV set in my cab.  The IR remote went right through it like it wasn't even there.

RandyT