... supply,so it can be widely used in mobile phone,camera,MP3,MP4 . For example, we can use the lithium battery that ... charge up aboveelectronic product,or use the power existing in interior directly . Of course, in daylight, we can also use thesolar battery from ... ,once the person left, it will switch off automatically. In condition of absence,the above function achieves the saving-energy and decreases ...