3 wire proximity switch help

[cropwell]

Are you powering up the BoB from the USB input or a separate power supply? The reason I ask is that USB supplies a limited current and you might not have enough power to work the BoB and more than 1 resistor. You may remember that I recommended that you did not use the USB port on the computer to power the BoB !

[cropwell]

Also saves the switches getting smashed by riding over the target rather than into end stops.

.

Been there, done that

[mikem]

No I'm using a separate 5v PS. The lights don't light up when it makes contact either. But when I put the Blue wire on the 12v ps with the + it's lights up brite

[cropwell]

I think we have the problem !

The earth return paths are not connected. The blue wire from the sensor should be connected to the 0v (gnd) terminals on both power supplies and also (of course) to the 0v ground on the BoB. This is the most likely explanation of the symptoms.

[mikem]

cropwell
I ran the brown + wire to the positive on the 12v transformer. Then I ran the blue - to the Ground on the 12v transformer and the BOB gnd then I put the black on the input signal and the switch lit up but wouldn't trigger. So I disconnected the blue just from the transformer to the BOB and it now works like it should. It's more sensitive and works great.

So no transistors.

Thanks Mike