ST sensors embed wake-up function: small functions solve big problems

Nowadays, various smart devices are gradually being used in people's lives. People's requirements for smart devices are getting higher and higher, and with them comes high requirements for device manufacturers to optimize power consumption. Sometimes, device manufacturers even have to give up some good functions because these functions need to be always on for a good user experience, so the power consumption bottleneck overrides the technical bottleneck.

In fact, sometimes changing your mindset and flexibly using some "small functions" of peripheral devices may solve big problems. The following article uses the wakeup (WU) function, a hardware-embedded function of the MEMS sensor of STMicroelectronics (hereinafter referred to as: ST), as an example to explain how it solves big problems.

Let's first briefly explain the WU function of ST sensors: Most ST three-axis acceleration and six-axis acceleration gyroscope sensors have this function built-in. It intelligently detects the current state of the device at the single sensor level and optionally informs the application processor through hardware interrupts for it to make the next action decision. What needs to be emphasized here is "embedded", which means that there is no need to spend extra money or sacrifice extra power consumption.

Next, let's see how this small thing can solve big problems:

Example: How can smart wearable devices light up the screen by raising the wrist?

Solution 1: The simplest method is that the application processor obtains acceleration data in real time, and then processes the data through a software algorithm running on the application processor to make a judgment.

Solution 2: The acceleration data is also collected in real time, but the hardware hub is used to process the data, that is, the algorithm operation is transferred to the hub, and the application processor with higher power consumption is put into standby mode. Although the application processor does not need to work all the time, the hub still slowly consumes the power of the device.

Solution 3: Use the WU function built into the ST sensor. Normally, the application processor is in standby mode. When the wrist is raised, the sensor detects the WU action and then tells the CPU through a hardware interrupt to run the algorithm for further confirmation.

Comparing the three solutions, solution one has a big problem with power consumption for wearable devices, especially for those devices that cannot be charged, so this solution can basically be abandoned; solution two has some optimization in power consumption, but at the cost of additional hardware costs; solution three uses the application processor in standby mode, and the sensor performs motion detection; in comparison, the advantages of solution three are obvious: it is simple and easy to use, has low power consumption, and does not increase hardware costs.

The above examples are just a starting point, and more interesting and practical functions are waiting for everyone to develop. In fact, in addition to the WU function, ST sensors also have many hardware-level functions, which are convenient for developers to choose. In addition, ST will launch hardware-level gesture recognition function sensors in the future, and they also support customization.

Welcome to follow STMicroelectronics AMGChina WeChat public platform. STMicroelectronics (ST; STMicroelectronics) is a leading global supplier of semiconductor solutions, providing customers with sensors, low-power Bluetooth and long-distance wireless communication chips, power devices, automotive products and embedded processor solutions. From energy management and energy-saving technology to digital trust and data security, from medical fitness equipment to smart consumer electronics, from home appliances, automobiles, to office equipment, from work to entertainment, STMicroelectronics' microelectronic devices are everywhere, playing a positive and innovative role in enriching people's lives. Contact email: st_amschina@st.com Official website:



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