A method for controlling a transmitter, comprising: awaking and initiating the transmitter by a trigger signal generated by a timer; detecting whether the transmitter receives an input control parameter from outside of the transmitter, and if yes, updating an input control parameter stored in the transmitter by using the received input control parameter; reading the input control parameter currently stored in the transmitter; performing operations based on the read input control parameter so as to control the transmitter to select one sensor signal from a plurality of sensor signals, amplify the selected sensor signal with a gain within a first gain range, and output the amplified sensor signal; and after determining that the transmitter has accomplished a task specified by the read input control parameter, resetting the timer, and entering into a sleeping state until the timer generates the trigger signal.