Variable Cooling Fan

[Janos]

Has anyone put together a variable cooling fan controlled by the hardware/OS?

The cpu temp is available, see:

The idea being that the fan is off when it can be; 20% on a hot day; and 100% when you start matrix sums.

[9600]

Not that I know of, but this is something I wondered about doing also. Should be simple enough to do by pulse width modulating a GPIO pin (high duty cycle = fast, low = slow) and buffering it — add a transistor — so that you can drive a fan. This would require a breakout board, and perhaps some GPIO logic/routing in the FPGA. Another possibility would be to pick up the I2C bus from the expansion connector and use an I2C fan controller.

Cheers,

Andrew

[Janos]

Thanks Andrew. I've read up a little on these options and it looks like an I2C fan controller is the way to go.