Proximity endstops not working

Machine: _K40

Board: Laserboard

Firmware: _Smoothie

Problem/ Question: I’m having a few issues. I just installed my laserboard today. I can move in X and Y, First, I have the proximity end stops in my machine instead of micro switches, then don’t light up when the gantry is in proximity of the switches, I’m assuming they aren’t powered. they read 5-30V but the led never comes on.
Second then the gantry isn’t moving the steppers buzz a lot, they never used to do that.

Any help would be appreciated.

Just measured the output from the laserboard and it’s only 3.3V, this is an issue… Do I have to replace the switches?

Hi Ron, welcome to the forum.

Let’s start with the basics. Can you post some photos of your LaserBoard, the wiring, sensors, and motors? If there are labels/ info on the sensors and motors please post those as well.

Any other details about your machine or photos you think might be useful would help. Let’s gather some information and then we’ll see what we can do to get things sorted.


Hello, thanks!

I can’t get a picture of the motor labels without taking things apart.

I took off the tape on one of the wires from the sensors, they are tied together and go to the 5v line on the Laser power supply, the Gnd and signal go to the Laserboard.
I did some testing, I see the laser ground is not connected to the limit grounds… when I measure between Laser PS 5V and limit ground I only get 2.5V. Do I need to remove the 5v line from the Laser PS and put it into the 5v line from the endstops? are the signal inputs on the endstops 5v tolerant?

Hi Ron, so if I’m seeing it right, you took the 5v wires from the proximity sensors (brown wires in the yellow circle) and ran them to the yellow wire which is 5v coming from your LPSU. Is that correct?

If you look at the labels I added above the endstop connector you’ll see the empty connector on the right side is 5v. You should be able to get 5v from that for your endstops.

I was hoping to see photos of the motors to get some specs, but if you can’t reach them then you can go ahead and check out the Knowledge Base article linked below about adjusting the current for the motors.

The stock config file is set for 0.4 amps for the motors, which works well for most K40 machines, but you may need to raise that number for yours. You can try to increase it by increments of 0.2 and then test it. Your motors can be warm, but should not get hot to the touch. (If you set the current too high it can damage the motors.)

I didn’t, that’s the way it came. I figured that might be the case but wasn’t sure if the endstops were 5v tolerant… I’ll see if I can find pis for that connector. they are JST style correct?

Ah, gotcha. Did you purchase it new or used? I don’t think we’ve ever seen a new machine wired up in such manner. Yes, the endstop connectors are JST style.

(We do have the connectors available if you need them: Connector Pack for Cohesion3D LaserBoard)

I purchased this brand new. I’ve wired up a new control panel but I haven’t touched the main board until now.

If you search the forum for “inductive” you’ll find a few topics where this has happened before. In short, you’ll need to connect the power wire from the inductive sensors to power from the LaserBoard itself. You can pull 5v power from a few different places on the endstop connectors for this specific application


OK, great I got the endstops working, as you pointed out I’m not worried about the noise from the motors anymore.

Now I’m looking into why the laser won’t fire, works from the test fire button. I’m going to look into this more, I think I saw something online about this… I’ll let you know.