Found issues with filament sensor

For all this time I thought the sensor was crap. I finally took it apart and much to my surprise, the R2 uses a simple mechanical switch. I replaced it with the one robo sent me a year ago when I started having trouble, but the problem persisted. They sent me a new ribbon cable assembly that goes from the LCD to the RasPi which includes the leads to the sensor, so I replaced that too. At the time they said they realized the shielding on that ribbon cable was not needed.
Ok, but problem persisted - the filament sensor kept triggering false positives even if there was filament in the thing. I disabled the plugin and went about my printing.

Today I decided to open up the GPIO connector, because I had tested the old switch with a multimeter and it functioned perfectly.

Here is what I found


The red lead is not seated in the connection properly. So it makes intermittent connection.
Hence the pins on the raspi sees intermittent open/ closed, and why the filament sensor doesn’t work reliably.

I’m going to use the old ribbon cable (with the cut connector) so that I have direct access to the two pins on the pi. Then crimp my own 1x2 connector (like the kind used on the old PC fans) and slide it over the two pins (red cable is connected to pin 39 and black to pin 40, GPIO 21 on the pi. )


Then, hopefully get this functionality reliably back.




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So, I wired up my original robo filament sensor by crimping it to the ends from an old computer fan. (Yellow and black wires)


Then I also routed an external sensor through the back and left its crimped 2x1 sockets inside the printer next to the pi.



So the nice thing is, if the robo sensor fails, I have another ready to go and if for some reason that one failed too, I can always just run a jumper across the pins on the pi, or cut the wires and short them to allow me to complete a print.





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Except I do care, because I want the unit to stop if there is a filament out, or broken in middle of long print.

 

yeah, but not unless you cancel the print. This way, I can short out the wires and keep on going.