Application Example (1-03)
Coffee Brewer A

Application Example (1-03)

Coffee Brewer A

Sense coffee grounds full


  • ・Display an alarm when the machine is full with coffee grounds.

Issues & Requests

  • ・Want to ensure detection of accumulated coffee grounds.
  • ・Want to isolate the sensor from the moisture of the coffee grounds.

Wet coffee grounds have low reflectance, and the shape of the reflective surface is not uniform, so general reflective sensors may not be able to reliably detect them. Also, moisture from coffee grounds can short-circuit the wiring of sensors.


  • ・Adopted model:
    Light convergent reflective sensor B5W-LB2112-1
  • ・This sensor is optically designed to detect objects with low reflectivity, with black for example. Therefore, it is effective for detecting wet coffee grounds with low reflectivity. Make sure that the sensor should be used within the specified operating temperature range (0 to 60 degree C).
  • ・The sensor can be isolated from moisture of coffee grounds by installing a transparent plate. Place the transparent plate in close contact with the light emitting/receiving surface of the sensor. If the transparent cover is separated from the sensor or is too thick, the transparent cover will be accidentally detected by the reflected light (see the red arrows in the illustrations below)​.

For details, refer to B5W-LB Series: Light Convergent Reflective Sensor User’s Manual.

  • Coffee grounds detection through a transparent cover
  • Recommended conditions:

*The possibility of detecting the object varies depending on the sensing object or how to install the sensor.
Be sure to conduct sufficient evaluation using the actual devices before staring practical use.

*Use this sensor within it‘s operating ambient temperature (-10-60°C).

Recommended models: