tv in mirror with sensor

[rickdog]

Hello! I am making a tv in a mirror for my home bathroom (basically an lcd tv mounted behind a two way mirror). I have seen adds for these things for public areas such as restrooms that show video footage for advertising purposes until someone steps directly in front of it (and obviously some kind of sensor) and the tv goes dark to expose only a mirror. I would love to know how to set mine up to do this. Somewhere I read something about an infrared ray sensor. Could this be what I would need? The change from tv to mirror is instant.Please advise. I have no idea. Thank you.

 

[(*steve*)]

The glass acts like a mirror when there is no light source behind it. Simply turning off the back light will make the image disappear and the (half silvered?) glass appear again to be a mirror.

I'd probably try to sense a person using a PIR, but passively sensing a person with any form of light sensitive element would probably work. Restrooms usually have fairly bright and even lighting. A person standing in front of a mirror is likely back-lit and will reduce significantly the amount of light reaching a judiciously placed sensor.

Varying light levels (and the relative small size) of your bathroom may make this harder to achieve.

 

[rickdog]

Hey Steve, thank you for your answer. I do understand how the change from mirror to tv takes place, and that a PIR (or even a motion sensor of some kind) could be used as a switch, so I guess my real question is....How would this be integrated into the tv's picture? Certainly these manufactured models don't simply cut the power to the tv. The change from mirror to tv is absolutely instant, changing back and forth every second or so if you stood to the side and waved your hand in front of it. The tv must go into some kind of stand by mode (still on, but black picture). Thanks again Steve, or to anyone that could help.

 

[(*steve*)]

I told you how it is done. (turn the backlight on the monitor on and off as required)