Week 4 (In Lab) - Major Progress!

Figure 1. A schematic showing how the relay-Arduino-pump circuit will work.

This week's lab yielded a lot of progress for the team on all fronts, as listed below:

• Dr. Boettcher pointed out that the solution to our electrical problem (the conflicting 5V DC and 120V AC output/input for the Arduino and aquarium pump) could be greatly simplified by using the relay that was included in the purchased breadboard starter kit, as laid out in the schematic in Figure 1. The team had previously not realized that the relay could be used for this switch, and this new solution eliminates the need for a separate power source or a custom AC outlet, plus all the complicated wiring involved with that process. 
• During this lab and under Dr. Boettcher's guidance, Parm and Le were able to cut the aquarium pump's power cord and strip one of the wires in preparation for soldering. The stripped wire and power cord can be seen in Figure 2. 

Figure 2. Severed power cord for the aquarium pump, with one wire stripped. 

• Michelle tested the aquarium pump and determined the level to which it needs to be submerged in order to work. The team also acquired two gallon-size clear plastic containers from the lab's resources that can be used to prototype and eventually build the actual PlantParent's water reservoir. These containers are fairly shallow relative to the pump and will require the team to make several new modifications, such as cutting off the bottom of the pump in order to let it sit lower in the container. 
• Davina continued to work on the Arduino and GUI coding and was able to make a sketch that controlled the brightness of an LED through serial commands sent to an analog pin. This is not yet integrated with the GUI, though the GUI can now search the computer's serial ports and find the Arduino. Once the two are fully connected and it is verified that the whole system works, the team will be able to modify the code slightly so that it controls the timing of the pump rather than LED brightness.