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Firmware for ATtiny45/85 based temperature dependent fan controller
C++ Makefile
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LICENSE
Makefile
README.md
bb_terminal.hpp
schematics.png
tiny_pwm.cpp
tiny_pwm.eep
tiny_pwm.hex

README.md

tiny_pwm original project

Firmware for ATtiny45/85 based temperature dependent fan PWM controller

See project page at http://www.nomad.ee/micros/tiny_pwm/

tiny_fan: modified for Ruideng power supply case with 5V fan.

See project page at Making Ruideng DPH5005 Power Supply Case Silent

Instead of PWM, simple voltage limiting circuit is used, so fan can be in one of three states:

  • OFF
  • HALF SPEED, with ~1.4V cut off by 1N4148 diode and 2N7000 FET
  • FULL SPEED with ~0.8V cut off by BS170 FET

During the tests I've found that 2N7000 had a bigger voltage drop than BS170 (at least in the batches I have), so I used 2N7000 together with 1N4148 to limit fan speed to the HALF_SPEED mode.

Schematics

tiny_fan schematics

Serial output example

ADC:303 ADJ:300 T:25 Speed:0 %
ADC:304 ADJ:301 T:26 Speed:0 %
ADC:305 ADJ:302 T:27 Speed:0 %
ADC:307 ADJ:304 T:29 Speed:100 %
ADC:308 ADJ:305 T:30 Speed:50 %
ADC:307 ADJ:304 T:29 Speed:50 %
...
ADC:304 ADJ:301 T:26 Speed:50 %
ADC:304 ADJ:301 T:26 Speed:50 %
ADC:303 ADJ:300 T:25 Speed:50 %
ADC:302 ADJ:299 T:24 Speed:0 %
ADC:301 ADJ:298 T:23 Speed:0 %
ADC:301 ADJ:298 T:23 Speed:0 %

Board

See details at http://achilikin.blogspot.com/2019/01/making-roudeng-dph5005-power-supply.html

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