After understanding ESP32-C3's power management feature and different low-power modes, users can implement different power management schemes to reduce power consumption during the development of their actual IoT projects. This section introduces how to optimise the power consumption of the Smart Light project, which is also used as an example in other sections of this book, by implementing ESP32-C3's power management scheme and using different low-power modes.
To save energy in general or obtain certification for energy consumption, it is necessary to reduce the power consumption of ESP32-C3 during operation as much as possible in the Smart Light project. As explained in Sections 12.1 and 12.2, when ESP32-C3 is operating in Deep-sleep mode, its LEDC function does not work properly, and its Wi-Fi and BLE connections cannot be maintained. As a result, ESP32-C3 can not receive control commands from the user. Therefore, a power management scheme that utilises Wi-Fi Modem-sleep mode, Bluetooth Low Energy Modem-sleep mode, power management, and automatic Light-sleep mode is commonly employed to minimise power consumption in smart light projects. After implementing this scheme:
When the light is on, the power management lock is acquireed to ensure that the LEDC works normally, while Wi-Fi and Bluetooth LE remain connected to receive the user's control commands. By using the Modem-sleep mode of Wi-Fi and the Modem-sleep mode of Bluetooth LE, the working time of the RF circuit can be reduced to reduce power consumption.
When the light is off, the power management lock is released so CPU can enter Light-sleep mode when it is idle to further reduce power consumption.
Implementing this scheme in the Smart Light project involves two steps:
Configure ESP32-C3's power management feature, enable Automatic Light-sleep mode, turn on Wi-Fi Modem-sleep mode and Bluetooth LE Modem-sleep mode.
Complete the operation of the power management lock in the application so the driver for LEDC dimming works properly.
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