Sensed sound level based fan speed adjustment

A system in a device, the system comprising:

• a microphone that detects sounds in a particular range of frequencies used by a program of the device;
• a fan motor that controls, based on an input voltage, a speed of a fan of the device;
• and
• a difference logic coupled to receive audio data including sounds sensed by the microphone in the particular range of frequencies, the difference logic being configured to determine, based on both a sound level of the sounds sensed by the microphone and a sound level generated by the fan of the device at a current fan speed, a voltage to apply to the fan motor so that a sound level of the fan is less than a sound level sensed by the microphone of sounds other than fan noise, the difference logic being configured to determine the voltage to apply to the fan motor based on a speed to noise transfer function that identifies the sound level generated by the fan of the device at the current fan speed.

A method implemented in a device, the method comprising:

• detecting a sound level of sounds sensed by a microphone, the sounds including a particular range of frequencies used by a program of the device, and the program receiving audio inputs in the particular range of frequencies via the microphone;
• determining a sound level of a fan of the device at a current fan speed, the determining including using a speed to noise transfer function to identify the sound level generated by the fan of the device at the current fan speed in the particular range of frequencies used by the program, the determining further including selecting one of multiple different speed to noise transfer functions to identify the sound level of the fan of the device at the current fan speed, each of the multiple different speed to noise transfer functions being associated with a different one of multiple microphones of the device, the selecting comprising selecting the speed to noise transfer function associated with an activated one of the multiple microphones;
• and
• adjusting a speed of the fan so that the sound level of the fan is less than a sound level sensed by the microphone that is attributable to sounds other than fan noise, and reducing how quickly the speed of the fan is adjusted by averaging the current fan speed over an amount of time.

A device comprising:

• a microphone configured to detect sounds in a particular range of frequencies;
• a fan motor configured to control, based on an input voltage, a speed of a fan;
• and
• a circuit configured to receive audio data including sounds sensed by the microphone in the particular range of frequencies, the circuit being configured to determine, based on both a sound level of the sounds sensed by the microphone and a sound level generated by the fan at a current fan speed, a voltage to apply to the fan motor so that a sound level of the fan is less than a sound level sensed by the microphone of sounds other than fan noise, and based on a speed to noise transfer function that identifies the sound level generated by the fan at the current fan speed.