Patent ID: 8598979

Claim:
A keyboard comprising: a fingerprint input unit to receive fingerprint information of a user; a storage unit storing a fingerprint model; a switch unit; a control unit connected to the fingerprint input unit, the storage unit, and the switch unit, wherein the control unit receives the fingerprint information of the user from the fingerprint input unit and compares the received fingerprint information with the fingerprint model stored in the storage unit, upon a condition that the received fingerprint information being consistent with the fingerprint model, the control unit controls the switch unit to be turned on, to output a control signal to power on a computer connected to the keyboard, wherein the control unit comprises a microcontroller, a battery, a first diode, a first resistor, and a second resistor, a voltage pin of the microcontroller is connected to a power source and a cathode of the first diode, an anode of the first diode is connected to a positive pole of the battery, a negative pole of the battery is grounded, the first resistor is connected between the positive pole of the battery and a first input and output (I/O) pin of the microcontroller, the second resistor is connected between the first I/O pin of the microcontroller and ground, a ground pin of the microcontroller is grounded, and an alarm unit comprising a transistor, a second diode, and a buzzer, a base of the transistor is connected to a first output pin of the microcontroller, an emitter of the transistor is grounded, a collector of the transistor is connected to an anode of the second diode, a cathode of the second diode is connected to the power source, the buzzer is connected between the anode and the cathode of the second diode; wherein when the battery is at a low level, a voltage of the node between the first and second resistors drops below a certain value, the microcontroller detects a voltage at the first I/O pin is less than a certain value, the first output pin of the microcontroller is at a high level, the transistor is turned on, the anode of the second diode is at a low level, the second diode is turned off, and the buzzer outputs a sound, to indicate a charge of the battery.