First working version

README.md

@@ -1,7 +1,24 @@
-Arduino Nano mit AtMega328p (old bootloader) einstellen in Arduino IDE einstellen.
 
+@author Kai Lauterbach (klaute@web.de)
+@date 13.4.2023
+@version 1.0
+@license GPLv3
+
+A tiny tank cooler.
+
+The fan is startet i case that the temperature reached 26°C and switched off in case it is down to 24.5°C again.
+
+Used components:
+
+Arduino Nano uses ATMega328p (old bootloader)
+PC fan 120mm 5V
+PWM D4184 MOS breakout board
+USB-C connector
+BMP280 breakout board
+
+Connections between hardware:
 
 D9 (Pin12) wird mit dem PWM-Eingang der PWM Platine verbunden,
 A4 SDA vom BMP280
-D1 SCK vom BMP280
+A5 SCK vom BMP280
 

firmware/firmware.ino

@@ -1,18 +1,18 @@
 
-#define FAN_PIN   12
-#define L_LED_PIN 13
+#define FAN_PIN    9 // D9
+#define L_LED_PIN 13 // D13
 
 #define BMP280_I2C_ADDRESS 0x76  // BMP280 conneciton: D1 = SCL; D2 = SDA
 
 // minimum value to start both fan's is 110
 // without queeking noise is 255
-#define FAN_ON_TEMP      26
-#define FAN_OFF_MAX_TEMP 24
+#define FAN_ON_TEMP      26.0
+#define FAN_OFF_MAX_TEMP 24.5
 
 #define FAN_ON_STATE  HIGH
 #define FAN_OFF_STATE  LOW
 
-#define BMP280_CHECK_INTERVAL_MS 60000 // every 60000 = 60 seconds
+#define BMP280_CHECK_INTERVAL_MS 2000 // every 60000 = 60 seconds
 
 float bmp280_temp = -99.9;
 uint32_t bmp280_lastcheck_millis = BMP280_CHECK_INTERVAL_MS;
@@ -60,7 +60,7 @@ void loop()
 
     Serial.println("FAN state: " + String(fan_state));
 
-    analogWrite(FAN_PIN, fan_state);
+    digitalWrite(FAN_PIN, fan_state);
 
     digitalWrite(L_LED_PIN, LOW);