### DESCRIPTION

Controller for small swamp/evaporative cooler. Logic is controlled through an Arduino Nano soldered to the controller board. Headers are provided to hook up inputs and outputs. Source voltage would be car batteries at 10 – 14.4 VDC.

Selector switch has four functions, no signal is to drain tank and close fan doors. Second position is fan only with fan speed based on potentiometer setting. Third position is manual swamp cooler with fan speed set though potentiometer. Fourth position is for temperature hover were the fan speed is varied to achieve and hold a desired temperature. Temperature is set using two buttons to lower or raise the set temperature. Information about the run mode, fan speed, temperature and set temperature are displayed on the OLED screen. Temperature and Humidity are read in by the DHT11 Temperature sensor.

### TECHNICAL DETAILS / COMPONENTS

DHT11 Temp Sensor
Buttons, momentary (3)

Limit Switches (2)

Float Switches (2)

OLED display (I2C)

Buzzer

Selector switch (four position)

Fan

Water Pump

Motors (2)

Valve

D1 NA

D2 Temp Sensor read

D3 Water Pump

D4 Valve

D5 Fan (PWM)

D6 Buzzer

D7 Temp down button

D8 Temp up button

D9 Selector 1

D10 Selector 2

D11 Selector 3

D12 Fan Door Open (H Bridge L293D)

D13 Fan Door Close (H Bridge L293D)

A0 Fan Door Limit Switch Open

A1 Fan Door Limit Switch Closed

A2 Float Switch Low Water

A3 Float Switch High Water

A4 OLED (SDA)

A5 OLED (SCL)

A6 NA

A7 Fan Speed (Potentiometer)

Component Value Quantity

Capacitor 0.1 uF 2

Capacitor 0.33 uF 1

Capacitor 1000 uF 3

Diode 1N4004 2

1X2 Header 1X2-3.5MM 13

1X4 Header 1X4-3.5MM 4

Resistor 2 Ohms 3

Resistor 1K Ohms 4

Resistor 10K Ohms 2

Fuse Holder 200 mA 1

Fuse Holder 3 A 1

Transistor TIP122 3

V Regulator L7806 1

### LEARN / TOPIC / BUILD INSTRUCTIONS