Low Energy Bluetooth (BLE) technology is a new technology introduced in Bluetooth 4.0 and above, which has the advantages of low power consumption, wide coverage, and fast transmission speed. It is suitable for wireless communication of many devices. Here are some steps that can be used to develop low-power Bluetooth outdoor speakers:

1. Select BLE chip: Firstly, it is necessary to select a suitable BLE chip and select the appropriate model and function according to the project requirements.

2. Design circuit and PCB: Design the circuit and PCB according to the design requirements of the selected BLE chip and speaker.

3. Writing firmware: Use C language or other programming languages to write firmware code, including BLE protocol stack, audio encoding and decoding, power amplifier control, etc.

4. Testing and debugging: After completing the firmware writing, testing and debugging are required to ensure that the speaker can work properly, BLE connection is reliable, and audio quality is good.

5. Optimize power consumption: After completing basic functional testing, power consumption optimization is required to reduce system power consumption and extend battery life, such as optimizing BLE connection process and adjusting power amplifier output.

6. Shell design and production: According to the design requirements, design the speaker shell, make a prototype, and then proceed with mass production.

7. Software development: Develop and collaborate with corresponding apps to achieve interaction and control between speakers and apps.

8. Marketing: After testing and production, sales and promotion can proceed.

It should be noted that the outdoor environment is relatively harsh, and factors such as waterproofing and dust prevention need to be considered, requiring protective design. At the same time, the use of low-power Bluetooth technology also needs to consider factors such as connection range and data transmission rate.