24v Limit/Home switches. How to..?

[Wal]

Apologies for resurrecting an old topic, but hopefully this extra info will help someone who isn't getting their head around running the proximity switches at a higher voltage and still being able to pass a signal back to the BOB at 5v.

Firstly, a huge thanks to Clive S who has explained (again and again with a great deal of patience) how this works. I'm kinda getting it now... It's something to do with dividing potential and works because there is already a resistor present in the switch (10K).

So to re-cap the details:

I'm using an NPN Inductive Proximity Switch part number: IQ11-D1NA05
The power supply for this switch will be an old 12VDC supply I have lying around from an old hard-drive (NOT 24V as in the subject)
My BOB is one of those Wantai BOBs that comes free when you buy the DQ860MA drivers

The first thing to say is that the stuff above is all well and good but, as Clive pointed out, for my purposes probably over-complicating the issue. If the currents that we're dealing with here were more substantial, then I have it on good authority that this method wouldn't work as matters become more complicated due to things like inductance/capacitance etc...

Right, here's a diagram of how I'm connecting everything together:



And some photos of how it looks on my newly bought breadboard...

Here's a reading of the voltage where it comes into the circuit - 12VDC as expected.



Here's the HIGH 5.72V reading taken from the BLACK wire whilst the switch isn't sensing anything. (The probe that you can't see is connected to GND)



And here's the LOW 0.69V reading taken whilst the switch is sensing - in this case a bottle-top.



I hope this makes things a bit clearer for those of you who are in the same boat as me (S.S. Clueless..)

IMPORTANT: Obviously, I'm a novice - barely even that - and have been guided by an expert - with that in mind, please exercise caution and get advice off someone who knows what they're doing before using any of the above information in your application.