For ARM architecture (M series microcontroller, the province electricity has always been a big bright spot, but it is well known that the use of wifi will greatly speed up the use of electricity, the power saving features do not to come out, for the project need low power consumption, can use BLE to transfer a small amount of data, and compared with wifi, BLE is a more focused on low power wireless protocol, at the expense of the bandwidth and connection distance, greatly reduces the power consumption, by adjusting the BLE connection interval and other connection parameters, users can choose to further reduce the bandwidth, in order to minimize power consumption, this does not need large amounts of data transmission in the Internet of things project is very useful,

materials prepared
RTL8722DM x 1
RGB LED x 1
Android/iOS smartphone

examples



In this example, through mobile applications for BLE UART transmission to control the PWM output and change the color of the RGB LED,



As shown in the figure below, connect the RGB LED to RTL8722 development board, according to the types of leds (a total of anode/cathode), may need to share the LED pin connected to 3.3 V or GND,



Make sure your smart phone has installed support BLE UART applications,
Open the application on your phone, scan and link to display as "AMEBA_BLE_DEV" panel, and then choose the controller in the application - & gt; The color picker function,

code description

RGB values in three consecutive bytes sent, and to "! C "character as the prefix,"!" Used to indicate the following data is the command, "C" character used to indicate the data is RGB values,

demonstration video

https://www.bilibili.com/video/BV1Xz4y1o7uZ/

Want to know more details, click on: https://www.amebaiot.com/cn/amebad-arduino-ble-pwm/