The explosive expansion of the wearable device market — especially for Health Tech applications — has resulted in unprecedented growth in the demand for sensors. Already a key component of smartphones, tablets, and other mobile devices, the need for more sensors is just starting to take off. The industry tracking firm MarketsandMarkets published a report last fall on the wearable sensor market, including a global forecast through 2020.

The report includes all sorts of sensors in its forecasts. In addition to the motion detection sensors that are essential to most fitness devices, it also includes optical and electronic sensors that measure heart beats to blood pressure. The report also covers sensors that can be used for user interfaces, such as cameras and microphones.

According to the report, this market will reach more than $654 million by 2020. Starting with last year, that’s a heady compound annual growth rate (CAGR) of 47.4% It looks as though the sensor makers are going to be kept busy for the next 15 years.