Bltouch sensor

I've got an annet A8 style printer and have recently been trying to set up autoleveling using a bltouch sensor and repetier firmware.
I'm using a ramps 1.4 board.
I initially tried installing the bltouch using the servo jumper to power the solenoid but this caused damaged by ramops board.
I now have it sdet up with 5v from the psu as in the diagram second from the top here, labelled "RAMPS1.4 + External(additional) 5V power Wiring":
[www.antclabs.com]
It seems to work now and I can control the raising and lowering of the probe using
M340 P0 S1500
and M340 P0 S700
however, when I run G31, I always get a low signal, I've tried using different endstop settings but it dosn't seem to make any difference.
Not sure if the probe was damaged with the rest of the board, I think this was due to drawing too much current from the arduino powering the solenoid directly.
Currently, I have the bltouch on the zmax pin on the board, I have the zmin and zmax pinouts switched in pins.h as I moved the z endstop to the max position (edit physical max position, so now the printer homes to z-max on the endstop, but the switch it hits at z max is plugged into the zmin, leaving the zmax available for the bltouch) and found that easier than moving the jumper. My configurations.h is attached.

Edited 1 time(s). Last edit at 08/05/2018 10:49AM by blabberjack.

I got a new sensor to see if I had damaged the electronics, but it has exactly the same issue. I tested the output with a multimeter, there is no change in resistance or voltage in the wire when the probe changes state. I can't understand how it could work without that. The indicator light turns on and off so something is going on, just nothing on the signal end.

on a ramps signal should change from 0v to 5v . (I don't have one on hand to try)

I do note in the docs "M119 can’t be used to see the state of the sensor end stop as the signal is only 5ms long (A CRO might work)"

so it only pulses the signal line for a very short time, so a multi meter probably wont see it, needs a scope

In your configuration.h you have

#define ENDSTOP_PULLUP_Z_MIN true           //
#define ENDSTOP_Z_MIN_INVERTING false        // true
#define MIN_HARDWARE_ENDSTOP_Z false         // true

and

#define ENDSTOP_PULLUP_Z_MAX true         //
#define ENDSTOP_Z_MAX_INVERTING true     // false
#define MAX_HARDWARE_ENDSTOP_Z true      // false

The min should be

#define ENDSTOP_PULLUP_Z_MIN true //
#define ENDSTOP_Z_MIN_INVERTING false // true
#define MIN_HARDWARE_ENDSTOP_Z true // true

and disable the max

#define ENDSTOP_PULLUP_Z_MAX true //
#define ENDSTOP_Z_MAX_INVERTING true // false
#define MAX_HARDWARE_ENDSTOP_Z false // false