Maker Pro
Maker Pro

tacho for comp fan

N

Neil Williams

Jan 1, 1970
0
how would a bar graph be conected to a tacho wire in order for it to show
the approx. speed of the fan when used in conjunction with a fan speed
controller
 
C

cpemma

Jan 1, 1970
0
Neil said:
how would a bar graph be conected to a tacho wire in order for it to
show the approx. speed of the fan when used in conjunction with a fan
speed controller

Via a digital-to-analogue converter and an LM3914, it's 2 pulses per rev
(RPM/30 Hz). Note the fan sensor output is generally open-collector, so
you'll need a pull-up resistor.

LM2917 is a suitable DAC, but it's far easier just to get a bargraph of the
fan voltage. My cpu fan RPM is damn near linear with voltage between 7.5v
and 12v, though it's y=mx+c, not y=mx.
 
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