Laser sensor for particle density detection

A laser sensor apparatus comprising:

• at least one first laser;
• at least one first detector circuit;
• at least one electrical driver,
• wherein the first laser is arranged to emit a first laser light in reaction to signals provided by the at least one electrical driver,
• wherein the at least one first detector circuit is arranged to detect a first self-mixing interference signal of an optical wave within a first laser cavity of the first laser,
• wherein the first self-mixing interference signal is caused by first reflected laser light reentering the first laser cavity,
• wherein the first reflected laser light is being reflected by a particle receiving at least a part of the first laser light,
• wherein the laser sensor-apparatus is arranged to reduce multiple counts of the particle,
• wherein the laser sensor-apparatus is arranged to interrupt detection of particles for a predetermined time period,
• wherein the predetermined time period is selected such that multiple detection of the particle is reduced;
• and
• a controller circuit,
• wherein the controller circuit is arranged to evaluate the first self-mixing interference signal provided by the sensor in order to count the particle,
• wherein the controller circuit is arranged to interrupt the detection of particles,
• wherein the controller circuit is arranged to interrupt evaluation of the first self-mixing interference signal provided by the sensor for the predetermined time period,
• wherein the controller circuit is arranged to generate a control signal upon detection of the particle,
• wherein the controller circuit is arranged to interrupt the detection of particles for the predetermined time period after detection of the particle.