3 wire proximity switch help

[Neale]

Make the switch point down, not sideways, and set the trigger pieces of metal just below it at each end of travel. It sounds as if this wouldn't give such accurate results but Jazz did some experiments a little while ago that showed this to work well.

[mikem]

Ok thanks make a lot of sence that way. I'll try it and see how it works.

Thanks Again

[JAZZCNC]

Make the switch point down, not sideways, and set the trigger pieces of metal just below it at each end of travel. It sounds as if this wouldn't give such accurate results but Jazz did some experiments a little while ago that showed this to work well.

Yes sorry I didn't look closely at the way you had the switches pointed. Neal is correct it does work very well I use the round type switch like this all the time.
Also saves the switches getting smashed by riding over the target rather than into end stops.

Keep the sensing distance small has possible for best accurecy.

[mikem]

So why I got you I have another question. When I hook up on switch to the 5V on the BOB and to the imput lets say on the y it works.Then when I hook up the X and add another transistor to the 5v neither will work. just when it's a single resistor on the 5v do they work as soom as I add another nothing works.

Any thoughts?

[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