Smart sensor thinks it's out of filament

I received my order today from 3DPC and installed all new fans (it’s the first time this printer has been quiet) and also installed a smart sensor. Now I didn’t see anything about disabling the old runout sensor and the BTT instructions don’t really say so I left it but I have some prints that really need to be done so since this sensor is giving me a false signal that it’s run out I disabled it in the menu for now, but I wanted to know what I need to check to get it working.

The B1 has a dedicated port on the side/back for the runout sensor right?

From the basic install video they have it looks like you have to change the sensor type from ‘on’ to ‘smart’ in the features settings menu, any chance you missed that?

Nope, it’s set properly. I’m reading now that marlin may not have the right runout detect distance., when this current print is finished I’ll have a look. after that I have to check if the pin on the board is getting the signal from the sensor. I’ve found the M43 command that can monitor the pins but I’m not sure how it works yet

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Dang, I was hoping it was something simple.

My next guess would be a marlin firmware setting/option (assuming the pin is getting the signal), but this one is out of my wheelhouse.
Best of luck hunting down the issue!

seems like this sensor is actually connected to the TFT not to the motherboard where marlin is. It’s hard to know what is actually running the machine with these displays in the picture. I don’t see a way to have a look at the TFT firmware like there is with Marlin

Hello Glenn And TurkeyONRye

Yes, If the Sensor is plugged in to the Back OF the TFT, then it will send the M600 Park Command through the Serial Connection to the Control Board.

I’ve Taken Advantage of this feature on Ender 3 Series with SKR mini E3 Boards, and TFT35 E3 Screen Combos. So i don’t have to Flash firmware when adding a Run Out

Well in my case it’s plugged into the back of the B1 in the smart sensor port. that I guess in turn is connected to the TFT so it’s updating the TFT now to the 4/28/21 firmware … hopefully that fixes it. if not then do you recommend cracking it open and switching the connector to the motherboard? It looks like my marlin firmware doesn’t have it enabled. when I did an M412 in the terminal it didn’t understand understand

Well Looks like there are some new doodads in this firmware version too. Screens diferent and there is a progress bar now on the home screen. but it doesn’t fix the filament sensor

Ouch, Fail… I’ll have to ask the other tech to send an email to BTT about this!

not really any answers out there. I’m not sure what role the TFT has in printing other than display but working in marlin at this point, especially with bed leveling is wildly diferent and marlin appears to have it’s own settings for everything. I’m happy to see what used to be called the plane test back in the TFT menu. there is a marlin version that doesn’t work at all that makes small circles for example. the preset temperatures for these bottled functions are not changeable in the TFT menu which limits their usefulness.

Hi @keith Did you find anything out about this issue?

I think I found the issue. I got to take it apart today and I see that the smart sensor wire has 3 circuits. The plug on the machine panel has 3 on the daughterboard inside but the daughterboard to the TFT is only 2 wire Green and Red, I think it should also be 3’ circuits in that harness. I can’t find a clear diagram on if that’s the way it’s supposed to be

Glenn so a big tree tech made a sensor that isn’t compatible with their own printer? Is that what it is looking like?

I think they made a printer thats not compatible with their sensor heh.

This is supposed to have 3 wires

A “smart” sensor will have three wires: 5V (or 3.3V), Ground, and Signal. A “dumb” sensor will is just a switch and will have two wires. However, just because they’ve used a three pin connector doesn’t mean it uses actually uses three wires. The “NC” generally means “No Connection”.

Well, that’s interesting. The sensor plugs into a port for it that’s mounted to a daughterboard inside. The sensor is 4 pin. The supplied cable is 4 pin to 3 pin and the other side of the board has this 2 wire cable to the TFT.


BTT has no Answer, RE: wiring…

Side Note: I thought NC = Normally Closed
Eg: on Creality Printers they are set for Normally Closed Switches. The Current is passing through when no filament, Current stops once filament is inserted. That’s When On Creality’s if loose wire or Broken wire you keep getting Filament runout error condition

Not being an electrical guy, I do ok but no formal training. Wouldn’t No connection and normally closed be basically the same? at least in this application.

Depends. In industrial controls NC and NO means closed and open in deenergised state. NC means closed contacts open means open contacts it comes from relay logic

I guess I’ll have to probe that with a meter and se if there’s power there