How to install and setup my filament SENTINEL?

Please ensure that your 3d printer is equipped with an LCD controller, otherwise, Sentinel will not work. Sentinel can work without LCD if you have Octoprint/OctoPi.

1. Basics

 

General

Sentinel VersionMinimum DiameterMaximum Diameter
1.75mm1.70mm1.80mm
2.85mm2.78mm2.92mm

 

The Filament Sentinel will detect the presence of your filament.Each Sentinel will draw 31mA. It requires 5V for power. The output logic is 3.3V and works with both 3.3V and 5V based microcontrollers.

 

FilamentLogicGreen LED
PresentHIGH – 3.3VON
AbsentLOW – 0VOFF

 

The IN label stands for a signal entry. This connector will only be used if you are daisy-chaining Sentinels together.

The OUT label stands for a signal exit. This connector will always be used, either for connecting to your mainboard, or to a daisy-chained Sentinel.

Where to setup SENTINEL on your printer

After the spool

Make sure it is stable. Attach it to the spool holder, on the table, or on anything that is fixed.

Before your extruder

Fix it on your printer, before the extruder.

Don’t install between your extruder and hotend. The extruder won’t push the filament past the Sentinel, no detection will occur!

PTFE tubing

When replacing the stock 4mm PTFE tubing with longer tubes, make sure the new tubing are at the right depth. Check the table below:

 

FittingInserted lengthNotes
Top46mm (1.75mm)52mm (2.85mm)As deep as it can get into the Sentinel
Bottom17mmFlush with the fitting. Do not compress the dust filter.

2. Wiring

Cable ColorConnection
BlackGround
BlueSignal
Red+5V

Connections

The “In” connector is only required when you have more than 1 Sentinel.
LabelConnectionCable
InSentinel (Daisy-chain)Daisy-chain cable (short)
OutMain BoardMain cable (long)

Pins

The easiest pins to use for the filament Sentinel are the followings:

  • Servo pins
  • Endstop pins

 

It is also possible to use the following:

  • Expansion pins
  • Communication pins

Connections examples

Servo/Endstop

Servo pins always have the right pins: 5VGround and Signal.

Most endstop pins will have the same 3 pins, and sometimes only Signal and Ground. If you only have these two, there should be a 5V somewhere else on your main board.

 

Pins examples

Color code: [Endstop] [Servo]

RAMPS 1.4

Choosing the Endstop pin from this example lead to the Digital Pin 2 as [DIGITAL PIN INPUT].

Choosing the Servo pin from this example lead to the Digital Pin 4 as [DIGITAL PIN INPUT].

Rambo 1.3

Rambo is a little bit less detailed on their general diagram. To find the pins association, the page “RamBo Development” must be accessed.

Choosing the X Max Endstop pin from this example lead to the Digital Pin 24 as [DIGITAL PIN INPUT].

Expansion

Some boards are very limited and a deeper understanding is required for connecting the Sentinel properly.

The Melzi is a good example of a minimalistic board as there are no additional servo pins nor endstop pins.

Communication pins and extension pins will be used instead.

The following documentation is required to determine the pin configuration:

Expansion Pins

In this example, expansion pins from JP16 can work, or any communication pins from JP17 too. Let’s consider EXT-A4 as our signal pin, as an analog pin can be used as a digital pin. Also, by choosing this pin, we will still be able to use the communication pins for any further add-on.

The EXT-A4 pin corresponds to the (PCINT4/ADC4)PA4 pin on the MCU (Microcontroller unit).

From the “Microcontroller with pinout” image, you can see that the PA4 pin is either the Analog Pin 4 or the Digital Pin 28. We will consider the Digital Pin 28 for the firmware configuration [DIGITAL PIN INPUT].

Microcontroller with pinout

3. Firmware configuration

Make sure your firmware has the filament runout feature, you need Marlin 1.1.0-RC7 or newer. If you are using an older version, contact your 3D printer manufacturer or update your firmware configuration manually.

Configuration.h

//#define FILAMENT_RUNOUT_SENSOR

Configuration_adv.h

//#define FILAMENT_CHANGE_FEATURE

Pins_[BOARD NAME].h

#define FIL_RUNOUT_PIN [REPLACE THIS WITH DIGITAL PIN INPUT NUMBER]

Make sure your firmware has the filament runout feature, you need Marlin 1.1.2 or newer. If you are using an older version, contact your 3D printer manufacturer or update your firmware configuration manually.

Configuration.h

//#define FILAMENT_RUNOUT_SENSOR
//#define NOZZLE_PARK_FEATURE

Configuration_adv.h

//#define ADVANCED_PAUSE_FEATURE
//#define PARK_HEAD_ON_PAUSE
//#define HOME_BEFORE_FILAMENT_CHANGE

Pins_[BOARD NAME].h

#define FIL_RUNOUT_PIN [REPLACE THIS WITH DIGITAL PIN INPUT NUMBER]

Make sure your firmware has the filament runout feature, you need Repetier 0.92.9 or newer. If you are using an older version, contact your 3D printer manufacturer or update your firmware configuration manually.

Configuration.h

#define EXT0_JAM_PIN [DIGITAL PIN INPUT]
#define JAM_ACTION 1

Simple pause

Settings / System Editor / config.g

M581 T1 E0 S0 C0

 

Custom macro trigger

Settings / System Editor / config.g

M581 T2 E0 S0 C0

Settings / System Editor / trigger2.g

Put any custom code you’d like to do once your extruder runs out of filament.
Example:

M83 ; relative extruder moves
G1 E-10 F600 ; retract 10mm of filament
G91 ; relative positioning
G1 Z2 F360 ; lift Z by 2mm
G90 ; absolute positioning
G1 X00 Y00 F6000 ; go to X=10 Y=10

4. Maintenance

Cleaning your SENTINEL

The sentinel clean your filament before it gets to your extruder and hotend. The filter should be checked every 1 kg to 10 kg, depending on your set-up.

  1. Loosen the bottom fitting

    Using a 10mm wrench, loosen the bottom fitting.

     

  2. Remove the filter

    Using a small tweezer, remove the filter from the housing.

     

  3. Clean the filter

    Remove the debrits and dusts that are stuck inside the filter. If the filter appears damaged, replace it with a new one.

     

  4. Install the filter

    Using a small tweezer, install the filter back in the housing.

     

  5. Tighten the bottom fitting
    Using a 10mm wrench, tighten the bottom fitting. Make sure the PTFE tubing does not compress the filter too much.

2 Comments

  1. Schweitzer says:

    So if i connect one side of cable to senitel and the other side to x-max, how do i get the pin number to write it in the code? Which number is x-max?

  2. Simon Duchaine says:

    You need to look inside your pins_[boardname].h file. There, you will find the #define X_MAX_PIN line with the default pin number assigned.

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