prototype of the complete circuit. The white connector at top of circuit
board (right of regulator) is where the 2-color LED is connected.
a 92mm fan with circuit mounted - with glue :-). The complete unit can be
used as a regular fan - just remember that the RPM is much lover and monitor
software have to be adjusted to avoid low-RPM alarms appearing.
simpler variant - just a regulator (5V with three diodes) for 7V. This is
a safer way than tapping 7V from the PSU by connecting the fan between the
+12V and +5V leads. For big fans - don't forget to put a small heatsink
on the regulator (up to 100mA can be taken without cooling, 1A max can be
delivered with proper cooling) - or put the regulator in the airflow of
the fan... ;-)