From 88a5d2a45ec3f7ebbe2e0e2a2a923283d78247a9 Mon Sep 17 00:00:00 2001
From: Ksan <djordje.ksan@gmail.com>
Date: Sat, 12 Apr 2025 22:55:14 +0200
Subject: [PATCH] Added basic functionality to control fans of nvidia gpu

---
 .gitignore |  1 +
 README.md  | 22 +++++++++++++++++
 main.cpp   | 69 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 92 insertions(+)
 create mode 100644 main.cpp

diff --git a/.gitignore b/.gitignore
index 259148f..27fbe49 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,3 +1,4 @@
+/fanControl
 # Prerequisites
 *.d
 
diff --git a/README.md b/README.md
index 441df3d..d188ccf 100644
--- a/README.md
+++ b/README.md
@@ -1,2 +1,24 @@
 # fanControl
 Simple script  for controlling your system fans
+
+Currently only works for nvidia gpu.
+
+To install just clone the repo and compile the code:
+<code> g++ -O3 -o fanControl main.cpp</code>
+
+Best used with tmux and running <code> sudo ./fanControl </code>
+<br>
+<h2> Setting custom fan curve </h2>
+To make your own custom fan curve just edit "TEMP_THRESHOLD" and "FAN_SPEED".
+<b>Example:</b><code>  TEMP_THRESHOLD[] = {30, 50, 80}; 
+                FAN_SPEEd[] = {0, 30, 50, 80};            
+</code>
+
+When the GPU temperature is below 30°C, the fans will not spin (0% speed).
+
+Once the temperature reaches 30°C or higher, the fans will spin at 30% speed.
+
+When the temperature reaches 50°C or higher, the fan speed increases to 50%.
+
+At 80°C or higher, the fans will spin at full speed (80%).
+
diff --git a/main.cpp b/main.cpp
new file mode 100644
index 0000000..151033b
--- /dev/null
+++ b/main.cpp
@@ -0,0 +1,69 @@
+#include <iostream>
+#include <sstream>
+#include <unistd.h>
+
+const int MIN_TEMP = 30;
+const int MAX_TEMP = 80;
+const int TEMP_THRESHOLD[] ={30, 40, 55, 60, 70, 80, 85};
+const int FAN_SPEED[] =	{ 0, 30, 40, 50, 60, 65, 80, 100};
+
+int getTemperature(){
+	std::string command = "nvidia-smi --query-gpu=temperature.gpu --format=csv,noheader,nounits";
+
+	FILE* fp = popen(command.c_str(), "r");
+	if(fp == NULL){
+		std::cerr << "Failed to run command to get GPU temperature." << std::endl; 
+		return -1;
+	}
+	char buffer[128];
+	std::string result = "";
+	while(fgets(buffer, sizeof(buffer), fp) != NULL){
+		result += buffer;
+	}
+
+	pclose(fp);
+
+	int temp;
+	std::stringstream(result) >> temp;
+
+	return temp;
+
+}
+
+void setGpuFanSpeed(int speed){
+	if(speed < 0 || speed > 100){
+		std::cerr << "Invalid fan speed:" << speed << ", speed must be between 0 and 100." << std::endl;
+		return;
+	}
+
+	std::string command = "nvidia-settings --assign 'GPUTargetFanSpeed=" + std::to_string(speed) + "'";
+	
+	if(system(command.c_str()) == 0){
+		std::cout << "Fan speed set to " << speed << "%" << std::endl;
+	}else{
+		std::cerr << "Failed to change fan speed." << std::endl;
+	}
+}
+int getFanSpeedFromTemperature(int temperature){
+	for(size_t i = 0; i < std::size(TEMP_THRESHOLD); i++){
+		if(temperature < TEMP_THRESHOLD[i]) return FAN_SPEED[i];
+		
+	}
+	return FAN_SPEED[std::size(FAN_SPEED) - 1];	// max speed
+
+}
+int main(int argc, char *argv[]){
+
+	while(true){
+		int temperature = getTemperature();
+
+		if(temperature == -1){
+			return 1;
+		}
+
+		std::cout << "GPU temperature: " << temperature << "°C" << std::endl;
+		setGpuFanSpeed(getFanSpeedFromTemperature(temperature));
+		sleep(5);
+
+	}
+}