i have reverse engineered the v2 probe board and figured out a way to get 5v off of the body.
there are 3 things to be done to do this
- cut traces on the board that connect the mounting screws bosses to the vcc(5v) plane pictured in red circles
- isolate the spring from the main body
- add 470-800 ohm resistor from one of the 6 balls to 5v pictured in blue(edit the picture shows ground on the pic on u1 use one of the other legs on the bottom just keep it out of the way of the mechanical suff up top)
a brief description on how it works from the factory
vcc comes in on the connector goes on the vcc plane the mounting screws for the pcb ar on the plane and transfers 5v to the body, it comes down the spring to the probe stem and connects all 6 ball contacts to 5v. u1-3 are analog and gates(or nand forgot the output polarity). so there is 5v on all 6 inputs, if any one breaks contact it triggers the gate and led comes on.
what i did was remove 5v from the body and supply it via a resistor to one of the 6 ball contacts so if any one of the 5 loose contact it triggers that channel. if the one that has 5v on it looses contact all 5 loose 5v.
i did some testing on the resistance needed to pull up the circuit around 1.2k ohm was the threashold for switching in software on the mr1 700 ohm completely dimmed the leds out. so i used a 470ohm resistor. a jumper can be used in its place but that puts machine board 5v on the stem just like factory but only on the stem. if it finds its way to actual ground this will short out the 5v rail on the control board. that is why i used a resistor also the stem body also triggers the probe when grounded.
the isolation of the spring to the body was shown on another post here by @alexw cna’t find it right away but essentially making a plastic spring pocket to the body.
also of note the ground plane of this board is on the other side of what is pictured- the side that gets mounted to the body. the only thing stoping the factory setup from shorting ground to vcc is the conformal coating on the board and annodised surface of the prob body.
