With rapid development of social economy, coffee is gradually integrated into people’s daily life as a kind of drinks. However, it is impossible for everyone to learn the traditional manual extraction method of coffee, instead, professional training and long-term practice are necessary for a good barista with a higher extraction level. In addition, high-quality coffee has strict requirements on extraction ratio and water temperature. Each producer has different extraction techniques. Even if it is the same person who extracts coffee, final quality of coffee would be influenced by emotional fluctuations inevitably. Therefore, coffee machine was born.

A coffee machine contains a variety of sensors, mainly including photoelectric water level sensor, pressure sensor, temperature sensor and flow sensor. Even if we have checked stability of pressure and temperature of a coffee machine, accuracy of the amount of powder and the standard of filling and pressing powder, the extraction time and taste of the coffee are still hard to control even with careful processing. Main reason causing the mentioned problem is flow which is one of the most overlooked variables in making coffee. Flow has an influence on flow velocity and stability of extraction, impacting final results of extraction. Controlling the flow is the key to improve the quality of the extraction.

The flow sensor is an essential component of a coffee machine. Main working principle of a coffee machine flow sensor is based on the Hall effect, that is, when an electric current flows through a conductor in the direction perpendicular to the applied magnetic field, an additional electric field that is perpendicular to the current and magnetic field can be generated and produce a voltage difference at the two ends of the electrical conductor. This change of flow is monitored by the voltage difference.

Misensor has provided our domestic client with the flow sensor that has the advantages of simple structure, reliable safety, sensitive response, long service life, etc. Our flow sensors are installed at the outlets of coffee machines. When water is flowing by rotor, magnetic rotor rotates and its rotate speed changes with the flow rate. At the same time, pulse signals are sent from a Hall sensor to the controller that can finally display the flow rate. It can not only effectively eliminate the disadvantage of outflow error, but also control the flow of water into brewing head. If pressure sensor and temperature sensor are also equipped with the machine, the produced coffee will have a rich and velvety taste.

With continuous expansion of coffee consumption market, coffee machine production has also grown at a rapid speed. With improvements of design and manufacturing technology, coffee machine has evolved from low-end (semi-automatic) to high-end (full-automatic) one, and from single functional to multifunctional one. Other than used in coffee machines, flow sensors can be also applied in various smart home appliances such as water heaters, water dispensers, etc. There is no doubt that the application range of flow sensors is going to be wider and wider, influencing our daily life step by step.