Autonomous energy development based on EVK1105 and UC/OS-II operating system (Part 2)

2.1 Functional requirements

The system is a multi-user player that can collect energy through solar energy and vibration, that is, it can collect energy through solar energy and vibration, and at the same time has the function of playing music through multiple user channels. Based on such an overall system function, the system has the following functions:

2.1.1 Energy Harvesting

1. Solar energy collection

The system's built-in solar panel can continuously provide power to the system when there is light. The player can be placed in the sun to charge while playing, and it can also be charged in the sun when not in use, and the power is stored in the battery for later use.

2. Vibration energy harvesting

Using the vibration energy conversion device, when the user walks or runs with the player, the vibration energy can be converted into electrical energy to power the player or stored in a battery for later use.

2.1.2 Player Function

1. Multi-user playback

The system adds a multi-user playback function, that is, the same player can meet the needs of different users at the same time. Through multiple channels, the player can play songs selected by multiple different users. This function breaks the limitation that the music player can only play a single song, allowing multiple users to share the same music player at the same time.

2. Wireless two-way communication

The system has added a wireless two-way communication function, which is mainly used for communication between the player and the headphones used by the user. In this way, when the user is indoors, the main part of the player can be placed on the balcony or yard where it can fully receive sunlight to obtain more energy, and only the small and light headphones can be carried with them. Considering that the user may need to adjust the playback status of the player at any time, the wireless two-way communication of the system is necessary, because under the premise of two-way communication, the user can change songs, adjust the volume, etc. without the help of the player, but only on the headphones.

3. Low power consumption, power saving

In addition to the efficient energy harvesting device, the system itself is also designed with a strong low-power power saving function.

In terms of hardware, in addition to the low power consumption characteristics of the EVK1105 platform, CMOS devices are used in the selection of peripherals, such as user headphones, remote controls and other devices to reduce overall power consumption.

In terms of software, a system sleep function is added. Because the system does not need to operate continuously, the system automatically enters a sleep state when it is waiting for the user to trigger it. When the user needs to use the player, the manual control of the system will cause an interrupt trigger on the software, causing the system to enter a working state, thereby reducing system power consumption.

4. LCD display

The system absorbs the advantages of traditional music players: it uses an LCD display to display the player's playback status, such as songs, volume, lyrics and other information, so that users can understand the system status in real time and adjust the system status according to their preferences and needs.

5. Assisted Search

The system is designed with relevant humanized functions to address the inconveniences people often encounter in their daily lives. People often encounter problems in their lives such as finding portable products as mobile phones and watches. Therefore, when a user only wears headphones and puts the player somewhere to charge, it may be difficult to find the player. In order to prevent this from happening, the system has added an auxiliary search function. The user only needs to press the search button on the headphones, and the player will respond with a sound, making it easier to find. Conversely, if the user cannot find the headphones, he can press the search button on the player to find the headphones.

2.1.3 System Architecture

In order to realize the functions of the above systems and coordinate the software and hardware, the overall architecture of the system is as follows:

Figure 1 System architecture

The system uses the UC/OS-II operating system as the basis of software functions, and uses it to implement user interface processing, data processing, user management, communication processing, memory management and device control. The functions of the operating system are combined with hardware such as power modules, EVK1105 platform, Bluetooth headsets, external storage and channel control to achieve the overall functions of the system.

2.2 Performance requirements

2.2.1 Energy harvesting efficiency

The energy harvesting performance of the system is shown in the following table:

Table 1 System energy harvesting performance

2.2.2       Player Performance

In addition to the power harvesting performance, the main performance of the player part of the system is as follows:

Table 2 Main performance of the player