alt Hacker NewsOne could go farther and complain that it's a waste of a microcontroller at all to control a fan when an analog circuit for fan speed vs temperature would work fine.
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pjc50 • today at 12:40 PM
Nah, it's a much lower part count and much simpler to put a microcontroller in. If you're concerned about cost cheaper parts are available.
True, a very simple analog circuit would be enough.
However the bane of analog circuits was that they age, so a control circuit that works perfectly today will drift and no longer work as intended after some years.
The second problem is that analog circuits need adjustments to set them at the exact desired parameters.
Adjustments can be done either by using an adjustable element in the circuit, e.g. an adjustable resistor or capacitor or inductor, or by measuring many resistors and/or capacitors and/or inductors and selecting the ones with the right values to be used by your device.
Redoing periodically the adjustments also solves the aging problem. However, both the initial adjustment and any periodic readjustments need a lot of work, so they are no longer acceptable in the industry.
When doing something for yourself, you may make an analog controller and the initial adjustment would not be a problem, but even in this case it would be annoying to keep track and remember something like having to readjust a fan controller every 6 months, to be sure that it still works as intended.