Initial version

main.c

@@ -0,0 +1,79 @@
+/*
+ *      Ferit Yiğit BALABAN,    fybalaban@fybx.dev
+ *      rpi-fan-control         2023
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <pigpio.h>
+
+#define TEMP_PATH "/sys/class/thermal/thermal_zone0/temp"
+#define FAN_PIN 17
+
+#define HIGH 1
+#define LOW 0
+
+int main(int argc, char** argv) {
+    int fd;
+    char buffer[6];
+    int fanRunning;
+    double temperature;
+    int threshold;
+    int variance;
+
+    if (argc != 3) {
+        printf("Expected threshold temperature and variance\n");
+        return -1;
+    }
+
+    threshold = atoi(*(argv + 1));
+    variance  = atoi(*(argv + 2));
+
+    if (!threshold) {
+        printf("Expected integer for threshold temperature: %s\n", *(argv + 1));
+        return -2;
+    } else if (!variance) {
+        printf("Expected integer for variance: %s\n", *(argv + 2));
+        return -3;
+    }
+
+    if (gpioInitialise() < 0) {
+        printf("Failed to initialize GPIO.\n");
+        return 1;
+    }
+
+    gpioSetMode(FAN_PIN, PI_INPUT);
+    fanRunning = gpioRead(FAN_PIN);
+    gpioSetMode(FAN_PIN, PI_OUTPUT);
+
+    fd = open(TEMP_PATH, O_RDONLY);
+    if (fd < 0) {
+        printf("Error opening temperature file\n");
+        return 2;
+    }
+
+    if (read(fd, buffer, sizeof(buffer)) < 0) {
+        printf("Error reading temperature\n");
+        close(fd);
+        return 3;
+    }
+
+    close(fd);
+    temperature = atof(buffer) / 1000.0;
+    printf("CPU Temperature: %.2f°C\n", temperature);
+
+    if (!fanRunning && temperature >= threshold + variance) {
+       gpioWrite(FAN_PIN, HIGH);
+       printf("Setting pin GPIO17 to HIGH\n");
+    } else if (temperature <= threshold - variance) {
+        gpioWrite(FAN_PIN, LOW);
+        printf("Setting pin GPIO17 to LOW\n");
+    } else {
+        printf("Pin GPIO17 is already HIGH\n");
+    }
+
+    gpioTerminate();
+    return 0;
+}