David Takehara
This is what a finished enclosure for Demeter will look like. Research into physical enclosures of hydroponic systems has led me to decide on a deep water culture-based design.
As it stands now, this a general block diagram of Demeter's hardware components.
Current Status |
Prototype
Demeter is aiming to be a self-sufficient hydroponic system. Allowing for a variety of plants to be grown all in the same system. This is done by allowing the user to set parameters such as light cycle, air/water temperature thresholds, humidity thresholds, pH thresholds, and nutrients concentration to meet the needs of what they are growing.
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As it can be seen on the existing solutions page, not many other hydroponic systems on the market offer this functionality. With Demeter, the user has control over the plant's growing environment. Allowing for faster growing, larger plants, and higher yields.
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Below lists some of the hardware being implemented on Demeter to offer this functionality.
Keypad
A keypad will be included in the MCU’s system design for user input. This keypad will communicate with the MCU and allow the user to cycle through the software states of the MCU. This keypad will be connected via the MCU’s GPIO ports.
Air Temp/Hum
For plant health, air temperature and humidity sensor will be implemented. Different plants need different ambient temperatures and relative humidity for the best and quickest growing cycles.
Electroconductivity
In a hydroponic system, nutrient density in the water can be measured through electroconductivity (EC) or total dissolved solids (TDS). By applying an alternating test current to the probe’s terminals, a resulting current will be produced. This current is proportional to the EC/TDS of the water and will be sent to the MCU’s ADC for interpretation.
LCD
A liquid crystal display (LCD) will be implemented by the hydroponic controller to provide the user with real-time measurements of the hydroponic system’s environment and allow the user to set desired environmental levels (temperature level, pH level, EC level, etc.).
Water Temp.
It is important to monitor the temperature of the water because of both the nutrients and pH fluids breakdown below 65 degrees Fahrenheit and above 75 degrees Fahrenheit.
pH
The pH level of a hydroponic system is very important to the plants overall health. To monitor the pH level of the water used in the hydroponic system a pH probe will be used and connected to an external circuit, for level translation, to the MCU’s ADC.
As stated above, Demeter is a work in progress. Even though the end of the quarter is here, I am still planning to get a real-time operating system (RTOS) working in Demeter. This will allow for a seamless user-interface (UI) to be implemented and for lower power consumption. I also plan on writing the required driver to get the keypad shown above working with my chosen microcontroller.
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I would like to state that both the pH sensor and electroconductive (EC) sensor are not included in this component list due to shipping issues during the 2020 covid-19 pandemic.