Patent ID: 8456129

Claim:
An outdoor monitoring system, comprising: a camera; a direct-current (DC) adapter for converting an alternating current into a direct current; a solar cell unit configured for converting light into electrical energy; and a power management unit, the power management unit comprising a controller, a rechargeable power source, a first voltage detection circuit, a second voltage detection circuit, a first switch, a second switch, and a switch circuit; the solar cell unit electrically connected to the rechargeable power source via the switch circuit, the rechargeable power source electrically connected to a first end of the second switch, the DC adapter electrically connected to a second end of the second switch via the first switch, the DC adapter electrically connected to the rechargeable power source via the first switch, a third end of the second switch electrically connected to the camera, the controller electrically connected to the first switch, the second switch, and the switch circuit, a first end of the first voltage detection circuit electrically connected between the rechargeable power source and an output end of the switch circuit, a second end of the first voltage detection circuit electrically connected to the controller, a first end of the second voltage detection circuit electrically connected between the rechargeable power source and the first end of the second switch, a second end of the second voltage detection circuit electrically connected to the controller; and the first voltage detection circuit configured for detecting a charging voltage of the solar cell unit for charging the rechargeable power source, the second voltage detection circuit configured for detecting an output voltage of the rechargeable power source applied to the camera, the controller configured for selectively connecting the rechargeable power source or the DC adapter to the camera according to the output voltage and configured for connecting or disconnecting the rechargeable power source to or from the solar cell unit according to the output voltage and the charging voltage.