Warning ------- This tool will allow you to write values to the SMC which could irreversably damage your computer. Manipulating the fans could cause overheating and permanent damange. USE THIS PROGRAM AT YOUR OWN RISK! Background ---------- I created this program because I was unhappy with my MacBook Pro running so hot and it annoyed me that Apple didn't make any way for end users to set fan preferences. This program will allow you to read and write values to the SMC using the AppleSMC kernel extension. The purpose of this is to show how to talk to the controller. I've made no effort to make it user friendly, however I'm releasing this in hopes that someone will take the next logical step and make a nice *free* GUI. I think it's absurd that some people are trying to charge for simple programs to manipulate this type of data. In my testing I've been able to lower the average system temperature by 15C just by running the fans at a low speed like 3500 RPM, which you can barely hear. Usage ------ # smc -h Apple System Management Control (SMC) tool 0.01 Usage: ./smc [options] -f : fan info decoded -h : help -k : key to manipulate -l : list all keys and values -r : read the value of a key -w : write the specified value to a key -v : version Fan control ----------- To decode: # smc -f To manually query and control: FNum - tells you how many fans are in the system To read data from each fan: F0Ac - Fan actual speed F0Mn - Fan minimum speed F0Mx - Fan maximum speed F0Sf - Fan safe speed F0Tg - Fan target speed FS! - See if fans are in automatic or forced mode [Replace 0 with fan #. In the MacBook Pro there two fans so this applies for 0 (left) and 1 (right).] To set a fan to a specific speed: FS! - Sets "force mode" to fan. Bit 0 (right to left) is fan 0, bit 1 is fan 1, etc F0Tg - Sets target speed, make sure you fp78 encode it (left shift by 2) For example, to force both fans to 3500 RPM: # python -c "print hex(3500 << 2)" 0x36b0 # smc -k "FS! " -w 0003 # smc -k F0Tg -w 36b0 # smc -k F1Tg -w 36b0 ..to force fan 0 to 4000 RPM and leave fan 1 in automatic mode: # smc -k "FS! " -w 0001 # smc -k F0Tg -w 3e80 ..to return both fans to automatic mode: # smc -k "FS! " -w 0000 Temperature sensors ------------------- TB0T TC0D TC0P TM0P TN0P Th0H Ts0P TN1P Th1H Light sensors ------------- ALV0 - Left ALV1 - Right Motion sensors -------------- MO_X MO_Y MO_Z