A little fun with automatic sinks

[evandude]

Where I work, the restrooms have automatic sinks, toilets, and urinals. judging by the faceplates of the sensors, they have to be IR.

Now, I would assume all they do is blast out some modulated IR and look for a reflection. (toilets would flush after the reflection was gone for a certain time, sinks would activate when the reflection was present) probably no encoding involved (no real need).

If that's the case, theoretically all you would have to do to trick them into turning on/flushing would be to blast them with modulated IR at their chosen frequency.

What made me think of this in the first place was that I was washing my hands today and when one of the urinals across the room (facing the sinks) flushed, one of the sinks near me turned on, so I wondered if one had activated the other.

Stupid little project, I know, but t would be pretty cool to just make a small device with some IR LEDs on it and when you walk into a restroom, all the sinks turn on and all the toilets start flushing madly. Not real good for water conservation, but it would sure make for some interesting reactions. :lol:

So, anyone have easy access to an oscilloscope and a restroom with automatic sinks or toilets? (I think I'd get some very funny looks trying it where I work)

 

[tansis]

Many a tv an' vcr engineer uses a simple gadget to test IR remotes
comprising of in IR photo diode and a transistor that drives a LED
in sympathy with any IR signal. Often found held directly to the side of a pp3 battery with sticky tape.

 

[evandude]

I thought of trying something like that soon after I posted... now that I can visualize how small it would be with a 9v battery (same thing? thats what we have over here anyway) I may have to try it sometime.

 

[zachtheterrible]

that is THE most brilliant thing ive heard all week!

Can you imagine walking into a . . . lets say movie bathroom with 15 urinals and one man standing in front of one. You press the button to your handheld remote and all of the urinals flush.

brilliance, pure brilliance. its on my todo list :lol:

 

[stevez]

I helped my son build a light-listener for a science project - featured in a Radio Shack book. It was a photocell, 741 op amp and an LM386 audio amplifier. Essentially you'd hear an audio output that represents the variation in light. It would "hear" remote controls quite well - along with lights, flames, etc. The photocell was nothing special but was sensitive enough. Build something similar to "listen" then see what you need to do. Be careful though - the boss might not be happy if maintenance has to work on a problem that never was there in the first place.

By the way, my son won the science fair but the teacher made it clear that it was not for his construction of the listener - he was too young to do that. He did get a lot of points for his understanding of how it worked and the explanations for the different sounds.

 

[evandude]

That's a cool idea, although if the modulated IR wasn't itself pulsed, and was near the typical modulation frequency, then I probably wouldn't hear much, last time I checked I couldn't hear 40kHz :wink:

 

[Nigel Goodwin]

That's a cool idea, although if the modulated IR wasn't itself pulsed, and was near the typical modulation frequency, then I probably wouldn't hear much, last time I checked I couldn't hear 40kHz :wink:

I would expect it's digitally coded, so you can't just trigger it with any remote.