I have created this board to control 2, 3, and 4 pins fans based on the temperature read from the DS18B20 sensor. it features an OLED display and a button for user input. Board works with a wide range of input voltage which is the supply voltage to the fan.

HOW DOES IT WORK?

The user specifies three temperature values:

• ON temperature (the temperature at which the fan starts working)
• Max speed temperature (the temperature at which the fan reaches maximum speed for most cooling - 4-pin fans only)
• OFF temperature (the temperature at which the fan turns off)

The board does its magic to operate the fan based on these inputs and presents current conditions to the user on the display.

CASE EXAMPLE

The three temperatures are 28, 35, and 26. When the sensor heats up to 28 degrees, the fan starts working with a 25% duty cycle. While the temperature rises the fan speed increases reaching 100% at 35 degrees. Fan blasting at full speed will cool down the sensor to 26 degrees when it switches off.

OLED shows an animation of whether the fan is working, fan speed and PWM duty cycle, sensor temperature, and programmed working range.

FEATURES:

• programmable temperature range
• OLED display with animated state of the fan and details about speed and temperatures
• changeable display orientation for different mounting positions
• footprint for either a 4-pin fan connector and 2-pin screw terminal
• onboard button for user input
• available with DIN rail mount

SPECS:

• Input voltage 5-30V (recommended 7-24V)
• Fan output voltage equals the input voltage
• RPM display (for 3 and 4-pin fans)
• Speed control (4-pin fans)

CUSTOMISATION:

• Soldered chosen fan connector / unsoldered
• DIN mount
• included temperature sensor (not by default)