Created for the purpose of syncing the RPM speeds of the Sycthe Flex II and Flex II slim models on an arduino. This gets rid of a weird noise frequency when both fans are stacked near each other.
An Arduino Uno R3 was used for this project
PWM signal is directly connected to the pins.
A pontimeter is hooked up to A0 input for RPM controller
Additional components were used on RPM signal to help get rid of noise:
Component lay used to filter noise, each RPM signal uses the following inpuit:
graph TB
%% Invisible link to position RPM to the left of the subgraph
RPM ~~~~subGraph0
RPM["PC FAN RPM<br>Green Wire<br>(Tachometer output)"]
subgraph subGraph0["Fan Tachometer Input Circuit"]
FAN_TACH["Tach Signal Line"]
R_PU["R1: 10kΩ<br>Pull-up Resistor"]
R_FILT["R2: 100Ω<br>Filter Resistor"]
C_FILT["C1: 0.1µF<br>Ceramic Capacitor<br>Noise Filter"]
MCU_PIN["Arduino input <br>(ATmega328P Pin 2)"]
end
V5["+5V"] --> R_PU
RPM --> FAN_TACH
R_PU --> FAN_TACH
FAN_TACH --> R_FILT
R_FILT --> C_FILT & MCU_PIN
C_FILT -.-> GND["GND"]
RPM@{ shape: rounded}
V5:::power
GND:::power
RPM:::rpmSignal
FAN_TACH:::signal
R_PU:::component
R_FILT:::component
C_FILT:::component
MCU_PIN:::micro
classDef power fill:#ffcccc
classDef signal fill:#ccffcc
classDef component fill:#ccccff
classDef micro fill:#ffffcc
classDef rpmSignal fill:#00D100
a 12v power supply with a 5.5x2.1 barrel jack is used, is used and split out to power each item: PC fans use a DC power to PC fan adapter, a Y cable splits that out to both fans. Fans are connected with jumper cables
4-Pin PWM PC fans use the following pin outs, and generally use these colors: Pin 1: GND ( black ) Pin 2: PWR ( yellow ) Pin 3: RPM ( Green ) Pin 4: PWM ( Blue )
In the case of all black wires, Pin 1, GND, is often stripped in gray. The PC fan connector has the notch directly on the edge connector as well for the gnd pin as, 4pin connectors are 3pin compatible the other notch is offset and not flush with the edge of the connector.
graph TB
%% Invisible link to position 12V to the left of the subgraph
V12 ~~~~subGraph0
V12["12V DC INPUT<br>(Power Supply)"]
subgraph subGraph0["Power Distribution Circuit"]
FAN1_PWR["Fan 1 Power<br>Red Wire"]
FAN2_PWR["Fan 2 Power<br>Red Wire"]
ARD_PWR["Arduino<br>Barrel Jack"]
end
V12 --> FAN1_PWR & FAN2_PWR
V12 --> ARD_PWR
FAN1_PWR --> GND["GND"]
FAN2_PWR --> GND
ARD_PWR --> GND
V12@{ shape: rounded}
V12:::power
FAN1_PWR:::yellow
FAN2_PWR:::yellow
ARD_PWR:::yellow
GND:::power
classDef power fill:#ffcccc
classDef yellow fill:#ffffcc