The capacitance sensing tag from E-Garde uses a special IC chip to detect capacitance. The capacitance changes depending on the amount and status. It measures the capacitance of the object and detect its state. There are a wide variety of methods. A typical one is water level detection. By attaching the detection electrode of this tag to the bottle, it is possible to detect the capacitance that changes moment by moment depending on the water level. It is possible to change the shape of the detection electrode according to the object in order to achieve the most accurate detection. This tag can be provided for both the UHF band and HF band.
Various methods have been developed for water level detection, and are widely used in factories and in similar environments. However, many of these methods require a power supply and wiring for data transmission. E-Garde has developed a capacitive sensor tag that can detect water levels.The tag does not require a power supply, and data is transmitted contactlessly via radio waves. Wiring is thus not necessary.
The sensor inlay can be attached to the exterior of liquid containers. As the water level increases in the container, the area of the sensor electrode covered by water increases. The capacitive sensor tag reads out the change in the indicated value.
This corresponds to the change in the dielectric constant. As the dielectric constant of water is relatively large (approx. 80 times that of air), there is also a great amount of change in capacitance when the water level changes. This means that when the water level increases, so does the measured capacitance value.
The capacitance sensor tag makes it possible to detect water levels even in opaque or colored containers, such as medicine or sake bottles, where the contents may be difficult to see. It is also possible to measure water levels in plastic containers as well.
E-Garde is from Japan and was founded in 2007 with a small team, which has now grown as an expert providing credential RFID products.