Sentinel™ Filament Detector

Dyze Design is a company focused on the world of professional 3D printing dedicated to the development and manufacture of components for 3D printers. Within the wide range of products they offer, their high-flow extrusion systems and their high-quality hotends stand out; which allow professional users to print at high temperatures, necessary when working with technical and advanced materials.

As a complement to its extrusion systems, Dyze Design has developed the Sentinel™ filament sensor. A filament sensor is a switch that acts based on the presence or absence of material.

These accessories are designed to eliminate the risk of unfinished prints by detecting the presence of material as well as its movement. For high-volume prints that require multiple spool changes or for specialty filaments prone to breakage, the sensor automatically detects when material has stopped arriving and pauses printing until it recognizes the filament again.

Sentinel filament sensor

Compatible with a wide variety of FDM 3D printers on the market, regardless of the firmware they use, the Sentinel™ sensor comes as a device just over 3 cm long. Its black metal casing houses a simple circuit board with a light sensor that checks to see if filament is present.

Image 1: Sentinel™ sensor. Source: Dyze Design.

The Sentinel™ filament sensor consumes 31 mA and requires 5V for power. The output logic is 3.3 V and works with 3.3 V and 5 V microcontrollers.

The operation of the system is based on checking the status of a light sensor located on one side of the filament while on the other side there is a light emitter. If at any time there is no filament between the emitter and the sensor, an electronic board turns on a LED as a visual warning and sends a Stop signal through a cable connected to the printer's control board. This command causes the print head to move to one side to make it easier to replace the empty spool with a new one.

The Sentinel™ filament sensor works with all types of filaments: flexible, translucent, opaque, etc. and is available in two versions, compatible with diameters of 1.75 or 2.85 mm. In addition, it is perfectly integrated into the firmware and if it does not detect material in the 3D printer, it will activate the “pause” routine.

As a complement, a dust-proof foam installed inside it makes sure not to allow external elements to enter the extrusion system, and thanks to the two screws provided, the user can install it wherever he wants. A 1m primary cable accompanies the sensor for connection to the 3D printer.

Daisy Chain

In situations in which unforeseen events must be reduced to a minimum, it is very common to place several sensors in series so that if one fails, the user has another. This is This is achieved through a “daisy chain” wiring scheme. When several sensors are connected in a daisy chain, the system compares the signal from its light sensor with that of the previous sensor. If both signals are positive, a positive output signal will be sent.

Dyze Design has its own Daisy Chain Cable designed specifically for the Sentinel™ sensor.

Image 2: Cable daisy chain. Source: Dyze Design.

The Sentinel™ filament sensor is the perfect solution to avoid failed prints when the print volume is large and a large amount of material is needed or for special filaments where the risk of breakage increases.