Method and apparatus for measuring remaining power level of device

An apparatus for calculating remaining electric quantity of a device, comprising:

• a detecting module configured to check status of flags, and trigger a password calculating module when a first flag is set, or trigger a total power consumption calculating module when a second flag is set, in which
• the password calculating module is configured to activate a timer to start counting, calculate a password, close the timer after finishing calculation of the password, stop counting to obtain time for calculating the password, reset the timer, add the time for calculating the password to a fourth register, and trigger a displaying module;
• the displaying module is configured to display the password and the remaining electric quantity, reset the first flag, and trigger the detecting module;
• and
• the total power consumption calculating module is configured to check battery voltage, obtaining a preset wake-up current value, a password calculating current value and a displaying current value according to the detected battery voltage and a pre-stored first data table, obtain a total power consumption by summing up a product of the wake-up current value and data in a first register, a product of the password calculating current value and data in a fourth register, and a product of the displaying current value and a result of a first preset value minus data in the fourth register;
• a remaining electric quantity updating module configured to update the remaining electric quantity according to the total power consumption and a second preset value, reset the second flag, and trigger the detecting module;
• and
• a real time clock module configured to calculate time of the device, and trigger a waking up module every first preset time period, in which
• the waking up module is configured to activate a timer to start counting, update a second register and a sixth register by adding the first preset time period to the data in the second register and the data in the sixth register, respectively;
• when the data in the sixth register is equal to a fourth preset value, set the first flag, clear the data in the sixth register, close the timer for stopping counting, obtain a time period for waking up, and add the time period for waking up into the first register;
• when the data in the second register is equal to the first preset value, set the second flag, close the timer to stop counting, obtain a time period for waking up, and add the time period for waking up into the first register.