I am having a problem getting a BLTouch to work on my Ender 3 V2. When I try to Autohome it to start setting it up the Z axis will not travel in the down direction. It will travel up fine and the X & Y axis’ work fine but it won’t go down. It’s as if the BLTouch thinks it’s triggered.
I have triple checked the wiring and have tried multiple firmware variations with the same results. I have compiled the latest version of Marlin bugfix myself, and tried the Creality and Smith3d versions. All behave the same.
When I turn on the printer the red light on the BLTouch comes on and it extends and retracts the probe a couple times. The red light stays on. When I hit the autohome icon it goes to the Z and X axis switches and then centers on the build area. It then cycles the extend/retract bit a couple times ending with the red light off and the probe extended but it doesn’t do anything after that. There’s a little blue light flashing rapidly inside the BLTouch housing while it’s just sitting there.
Is there something I may have missed or could it be a bad sensor?
This is how it should be wired and make sure the wires are plugged in firmly as the DuPont cables aren’t what should be plugged into that connector. It should be a 5 pin JST connector which is what i put on mine.
My wires are Brown, Red, Orange (Yellow), Black & White. My board is the 4.2.2. I have checked the firmness of the connector a couple times. The first time I tried it I had actually put a dab of hot glue to hold them securely but have since removed that for troubleshooting purposes.
Well $40 later for another BLTouch and the problem is still there. No down travel on the Z axis. What could possibly be causing this? I have searched the interwebs and it doesn’t seem to be a problem for anyone else because I can’t find any other cases of it. Pulling my hair out.
That’s how you know you’ve taken up a hobby! I had my own bout of hair-pulling when we had a power outage 17 hours into a 21 hour print. Not only did I lose the print, but I could not make contact with my Octopi after the event. Even after re-flashing, it kept giving me the silent treatment. Finally discovered that for no good reason my router no longer lets my Pi connect via 5GHz wifi. I had to switch over to 2.4GHz to get it to connect.
A thought occurred to me. I ordered the USB power block device that DrVAX mentioned in his video, but I’m still waiting to receive it. I’ve noticed the phenomenon DrVAX mentioned in his Octopi upgrade video that if you have a normal USB cable connected to the printer, the controller draws power from the USB when the printer power is off. In my case, I notice the BL-Touch is even illuminated red even with the printer power off–it’s drawing current from the USB cable. If you have a USB cable connected to your printer without the power blocker device, try disconnecting the USB cable whenever the printer is off and only reconnect it once the printer power is on. Essentially, the hypothesis is that maybe the weak amount of power being supplied by the USB when the printer PS is off is putting the Ender controller in some kind of funk that affects your BL-Touch. Just an idea.
Well, it appears to be a problem with the extension cable. If I plug the sensor into the board with the short cable it works correctly. Now to figure out what’s wrong with the cable. Wish I tried this before I bought another BL-Touch. Fortunately I have another Ender 3. I’ll put it on that one.
Here’s the wiring for the cable that came with my Bltouch, I soldered on the 5 wire plug. This worked on my Ender 3 v2 but was a tad short. I have a v4.2.2 board and used Smith3d firmware