The Arduino Mega is a microcontroller board with digital input/output pins, analog input pins, a USB connection, I2C connections, and a reset button. The team was able to successfully connect to the Mega board. 

Coding/Circuit Set Up

The EC (green), pH (red), and temperature (black) sensors are connected to their respective circuit boards, which are powered through a Whiteboard device connected to a Raspberry Pi. Each circuit board displays a blue light when connected. The Raspberry Pi will be replaced with an Arduino Mega and a new, Arduino-friendly Whiteboard will be purchased.  Without the Arduino Whiteboard, we cannot connect the sensors to the Arduino board, but each piece worked when using a temporary Raspberry Pi.  

Coding/Circuit Set Up

When the code is uploaded and each probe is placed into the water bin, all three sensors registered values that were expected. The display screen below shows each board taking new readings and outputting them to the user. 

Below are the Arduino code files for the sensors:

The CO2 sensor is connected directly to the Arduino Mega board. This device was not accurate, providing the team with readings of CO2 as high as 9500 ppm (which is above the 420 ppm level that was expected). Efforts to recalibrate and change the code for the sensor were made, but it could not be fixed. The team is currently looking into purchasing a new CO2 sensor.

Coding/Circuit Set Up

The CO2 sensor has three connection wires: power (red), ground (black), and an analog input (blue). When wiring to an Arduino, the code is set up to connect the blue wire to analog pin A0. This can be changed in the code if needed. The sensor has a three-minute warm-up phase and will display readings in the Serial Monitor in Arduino IDE. An image of CO2 readings was taken after these three minutes, yet the results were still higher than expected. This sensor was likely damaged and needs to be replaced. 

Below is the Arduino code file for the sensor:

The humidity and temperature sensor is connected directly to the Arduino Board. Once the code was running, this sensor returned the expected temperature and humidity values.

Coding/Circuit Set Up

The humidity and temperature sensor has four connections to an Arduino board: power (Vin to 5V), ground (GND to GND), a SCL connection (SCL to digital pin 21), and a SDA connection (SDA to digital pin 20). When wired and the code is uploaded, open the Serial Monitor in Arduino IDE to view the relative humidity and temperature of the room. Both values were in an acceptable range for the room the team tested in. 

Below is the Arduino code file for the sensor:

The peristaltic pumps will be used to move a specific amount of pH formula and/or nutrient solution into the tank when needed. The pumps are connected to a wall outlet and an Arduino board. Once the code was running, the pumps moved the testing water into and out of the tank at accurate amounts. 

Coding/Circuit Set Up

The pumps have two different connections: a power connection and a wired connection to a microcontroller. The power connection is plug-in operational. The wired connection includes five wires. Four are used to connect to the microcontroller using I2C. When wired and coded, open the Serial Monitor in Arduino IDE. A list of commands can be used to operate the pump by typing in the command window. The commands are included in the code file. 

Below is the Arduino code file for the pumps:

The water pump will move the water from the tank to the pipe holding the plants. 

Coding/Circuit Set Up

The project has two LED lights to supply plants with a sunlight replacement.  

Coding/Circuit Set Up

Relays are switches that open or close a circuit connection by using an electronic component without mechanical operation. Relays are mainly used to convert a small electrical input into a high-current output, or vice versa. The relays will allow the projects' high voltage/current components to be connected and controlled by the microcontroller. These components are the lights, water pump, and fan. Two of the four relays were able to be manually operated by the team. 

Coding/Circuit Set Up

To test the relays, a battery pack was connected to one side of the relay and the switch within the relay was manually opened and closed. When closed, the relay made a clicking sound and a red light turned on. A multimeter was connected to view the relay's switch opening and closing. 

Below is an example of how to wire the relay:

With the new Arduino Whiteboard, the EC (green), pH (red), and temperature (black) sensors can be connected to the Arduino Mega board. The whiteboard allowed each sensor and probe to successfully connect to the Arduino Mega, displaying a blue light. 

Coding/Circuit Set Up

A fan will be connected to the hydroponics system to move air in and out of the system. This will filter out oxygen gas and filter in CO2 while helping regulate the temperature and humidity of the system. 

Coding/Circuit Set Up

The CO2, temperature, and humidity sensor is connected directly to the Arduino Board. Once the code was running, this sensor returned the expected CO2, temperature, and humidity values.

Coding/Circuit Set Up

The CO2, temperature, and humidity sensor has four connections to an Arduino board: power (red wire to 5V), ground (black wire to GND), a SCL connection (yellow wire to digital pin 21), and a SDA connection (blue wire to digital pin 20). When wired and the code is uploaded, open the Serial Monitor in Arduino IDE to view the CO2, relative humidity, and temperature of the room. All values were in an acceptable range for the room the team tested in. 

Below is the Arduino code file for the sensor:

The LCD screen will display the sensor readings taken within the system. The LCD is connected directly to the Arduino Board using an I2C connection. 

Coding/Circuit Set Up

The LCD Screen has four connections to an Arduino board: a VCC (power), GND, SDA, and SCL. When wired and the code is uploaded, messages should display on the LCD Screen. The backlight of the LCD screen may be too bright to see the messages. If so, take a small screwdriver to turn the blue potentiometer on the back of the LCD. This will increase and decrease the brightness of the backlight. Adjust the backlight until the message is viewable on the LCD Screen.

 Below is the Arduino code file for the LCD: