Temperature and humidity controlled fan
PRINCIPLE: Basically this device is used to switch on fan, when conditions are good for drying wheat. Conditions are good when the humidity is lower than RH<70% and T<24 ยบ C. When these conditions are met, the fan has to switch on. The fan is big and needs to be switched on rarely and switching on the fan frequently may kill the fan starting schematic. Therefore it doesn't need to change the relay state frequently. HARDWARE: I am using for this Arduino Mini Pro 3,3V, Nokia 5110 LCD, relay, LEDs, AM2305, BC547 transistors and voltage adjuster. The brain of the whole thing is Arduino, directly is connected to it 5110 LCD, relays are being run through the BC547 transistors. AM2305 sensor is connected to Arduino pin. SOFTWARE: For controlling the LCD is used LCD5110_Basic library. The LCD displays info from sensor: temperature, humidity, temperature limit, humitity limit, relay state and countdown timer. The code checks sensor every 30 seconds and updates display accord