Magnetic proximity switch instrumentation
 

Yes I have an application for that.
2 things come to mind.
On the suburban I installed grill shutters. Only problem is they are 100% manual. I open them in the warmer months and close them when it gets cold.
Kind of a problem when you can get up one morning and there is frost on the vehicles, then less than 36 hours later it can be 80'F. Happens quite often in the high plains. I could easily put an air cylinder on there to open and close it, but knowing my luck about the time I start to trust it and not check it, then it will jam closed on me.
The proximity switches I have found are food grade rated to live in the hot wet soapy wash down environment found in food processing factories. Should do fine under the plastic grill of a vehicle.
That will display fully open versus fully closed confirmation.

The second application is pretty much the same thing, but completely different.
Using 2 reed switches on an air cylinder rig that I put together to install on my variable geometry turbo, but never did. The reed switches just sense when the piston inside the air actuator reaches a certain position.

I should have the prox and its cable's part number tomorrow to Wednesday at the latest once I confirm the application and activation. Things such as do they really work on 12 volts (I believe they do), will they pick up the stainless steel my grill shutters are made of or do I need to attach a magnet for it to pickup on?
Will the reed sensors work with the air cylinder rig I already built or do I need to find another cylinder or different sensors from the ones I have in mind?

Then post pictures, because we all love pictures of shinny things with LEDs that light up.

You'd have to check the datasheet for the proximity switch. Some of them will detect iron. I'd have my doubts about stainless.

If you can get a cylinder with a switch in it, that would be a better and easier option IMO.

The one that will best fit my needs is part number IE5295.
It is activated by being in close proximity to 304 alloy stainless steel, regular steel or a magnet.
It is a normally open switch single pole single acting switch.
The water proof wire connector part number is E18017. It is long 4 prong screw on connector, fits all your small 4 prong proxs and switches.

The sensor element is made in Germany and is not cheap made in china garbage.
Search ebay to see some now, there are 2 sensors and a bunch of cables on there now.

This prox is wired as follows.
The brown wire goes to +DC power source.
The Blue wire goes to -DC power.
These 2 wires power the sensor.
The black wire gives you the I/O signal up to 300ma when the prox is made.

And yes it does work perfectly on 12 volt DC power. Min voltage rating is between 10 and 11 volts.

The cylinder prox to use looks like a D-A54, a wired magnetic reed switch.
You can use the appropriate cylinder connector to attach to a cylinder or a hose clamp.
You can get good ones made in Germany or cheap ones made in china.

If size matters the prox you want is an IE5366 its tiny. The sensor its self is only about an inch long. (this is tiny compared to the IE5295).
I believe they use a female pico (8M) type cord. I don't normally use these so I will need to double check to make sure these take the pico cord.
If 1 inch over all element length is too short for you then there is IE5349, its about 1-3/8 inches long.
These inductive proximity sensors can get a lot smaller than this.