Turbo Mini Forums

Yes, the voltage at Vcc (measured with the same DVM) compared to the voltage at the Hall switch will be interesting. It will prove the effectiveness of the way the MS-Extra diagram that you are using, is at using the 5V supply to pull-up the output of a 12V device.
I can't get my head around it properly at the moment but it doesn't seem "right".
And if you have any resistance at your soldered joints.... Well, shame on you !!!

Schrödinger's cat - so which one am I ???