Would it be possible to create a passive homing device?

Sounds like a passive RFID.

There already is one; it’s called Mom.

@phaedryx , I was not aware of RFID before, but a passive RFID is exactly what I had in mind. For others unfamiliar with RFID check out this site. According to the article, passive RFID devices are pretty cheap. I don’t know how much a detector would cost.

What you want is called a real-time locating system.

Here’s a possible solution: You can use several RFID-like tags, each of which is tuned to a different radio frequency. Whenever a specific radio frequency is broadcast throughout your home, the different tags resonate in different ways. There would be several electronic listening points in each room, and the data from the listening points will be enough to triangulate the location of the specific tag within the room.

Interesting idea, but how much is this going to cost?

Of course not.

The best advice that I can give (since there’s no reasonable response to the oxymoronic “passive homing” device – “homing” being an action, after all) is to modify your habits.

When I get home at night my keys are hung up on the back of the kitchen entry door. Always, first thing. When I change clothes, my wallet, pen, shirtpocket notes and cash go in a bowl at the corner of my dresser. My belt is hung on a hook by the dresser. Always, second and third things.

My glasses stay on a lanyard around my neck, or when I go to shower or to bed, they lay on top of the bowl with my wallet, etc.

When I travel, then I have to adapt and “make new habits” for wherever I am, so that I always know where things are going to be. If I break my routine, there’s no telling where things can end up.

I would install a system of cameras in every room. The cameras would input data to a central processor programmed to track the movement of things like keys and glasses. The system would remember where everything is, where things were last seen, who moved them and where they went.

@CWOTUS , I had a perfect system. I had a small bag in which I placed my wallet, keys, watch, cell phone and company ID tag. The bag never left the kitchen. I somehow managed to lose track of it.

You mean like this?
http://www.hammacher.com/Product/78558?cm_cat=ProductSEM&cm_pla=AdWordsPLA&source=PRODSEM

That is a neat device, but not quite what I was looking for. It requires having the foresight to mark the location of what you will later need to find.

How about Tile?

Perhaps, then, in the technology arena, you’re looking for something like this.

@hearkat , @CWOTUS Those seem like what I want. I am glad to see that high tech companies are working on the problem of people losing things. I find especially intriguing the idea of having the Tile app on people’s phones forming a community of searchers for missing items. Both your devices seem to require batteries, which may not be such a bad thing if the batteries last for several years.