Building BUNYAG, the Mom-Approved Plant Savior.
Learn how BUNYAG, an automated watering system, can simplify plant care, especially for busy moms.
Introduction
Discrete Structures is a fundamental subject in any ICT course since it deals with mathematical structures that are fundamentally discrete rather than continuous. This subject is crucial because it provides the mathematical foundations and tools needed to understand and solve problems in computer science.
As a final project for this subject, we were separated into groups of five to six students and we were tasked to create a device with a functionality that can be used from day to day living with only the use of integrated circuits. For context, an integrated circuit or IC is a combination of multiple components such as transistors, resistors, capacitors, and logic gates. These components have specific functions that work together to manipulate electricity to perform various functions.
After each student has been grouped, me and my groupmates brainstormed ideas and on the very last day of the submission of the proposed project, we settled for a device that can automatically water plants on a specific time of day and based on a temperature threshold. This idea came up because we thought that at present, the rising heat was not only dangerous for people, but for plants as well. After the submission, we researched ways on how we could achieve such a function. Unfortunately, our device functionality was not possible with only the use of integrated circuits and would require programming. For that reason, our group had to think of a different approach. We had the idea to have the same function, but the execution would be different.
What Kind Of Approach Would This Be?
This would be a semi automatic approach where the user will press a button and the device will water the plants for a certain duration. And to complement this function, we also decided to add a water level detector on the water container of the device to indicate that it is almost empty. This would be done using an LED which will light up when the water level has reached close to empty, indicating that the user needs to refill the container.
Project Start
Our group skipped a few steps here and there and started by researching what integrated circuit would fit our functionality rather than what logic gate it would utilize. Eventually, we stumbled upon the 555 Timer IC. A versatile and widely used integrated circuit that can be configured to perform various timing and oscillation tasks. Its primary functions include generating precise time delays, oscillation, and pulse width modulation. It has three modes: A-stable Mode, Monostable Mode, and Bi-stable Mode. We won’t dive into each mode, just the ICs monostable mode since it is perfect for our device functionality. In monostable mode, the 555 timer generates a single pulse of a specific duration in response to an external trigger. Once triggered, it returns to its stable state after the pulse duration, which is exactly how our device functions. Right after, our group started simulating in Tinkercad to figure out how to set up the timer IC in monostable mode free of mistakes and financial loss.
Collection of Materials
After many attempts, we managed to get our setup in Tinkercad to work with the output being an LED. At this point, we were confident enough that it would work so we decided to buy the materials needed for this project and started working on this project. The materials were the following:
- 9v Power Supply (2x)
- NE555 Timer IC
- Resistors
- Capacitors
- Transistors
- 7404 Inverter
- 5v regulator
- LEDS
- Wires
- Breadboard
- Housing
- Tube/Hose
The Problems We Faced.
We thought it would be as simple as replacing the input (LED) with a water pump, but we were very wrong. It took us days of researching as to why it works with an LED but not a water pump. We were tired of searching so we decided to ask around in a private Facebook page about circuits. Luckily for us, the community was very engaging and everyone was willing to interact. A few people commented on our post and gave solutions, but this one guy’s suggestion was what helped us solve our problem. He told us that our setup is only strong enough to power LEDs because the power is being dissipated because of the resistors. By the time it reaches the output, the voltage would not be enough. He proposed that we use a relay module because of two reasons. First is to make the input from the Timer IC the switch that turns on the module, and so that the water pump can have its own separate power supply that is closed, and will be open once the relay receives an input.
After the advice given to us, we decided to buy a relay module and follow tutorials on YouTube on how to properly set up the relay. After which we were able to set up the relay to be normally closed and open when input is received. And viola, all we have to do now is add the pipe to the water pump and our first function was working properly.
Second Functionality
After finishing the first function we moved over to the water level indicator aspect of the device. We took advantage of the conductivity of water so that we can use it as an input. The whole concept of this device is that the water acts as a conductor, two wires will be placed at the bottom of the container, one of them being the ground, so when water level rises and touches a wire, the circuit between that wire and ground is complete. Then, the wire will be connected to a NOT gate so that if there is water, meaning there is a connection, then the output on the LED, rather than on, will be off. But if no connection is established, the output, rather than off, will be on. Perfect indication that there is no water left inside the container.
Thankfully there were a lot of sources online on how to build this type of device so we had an easy time trying to figure out how this device works. With the use of the 7404 inverter, we managed to create the second functionality, much faster than the first one, mind you. Now all we had to do was combine both functionalities and design the project housing.
Finalizing
The next step was combining both devices and making the project housing. We made the housing out of an old cardboard box. Instead of having a very basic rectangle shape as its housing, we decided to have a sort of “L” shaped box. The container would be sticking out the top for easy refill, and the indicator right beside it, while the rest of the device goes on the horizontal part of the box. With two levels in it, the first level was the timer function and the water level indicator function was on the second. We also allowed the second level platform to be detachable so that if any issue were to occur at the device at the bottom, we could easily make repairs.
Testing
Finally, we decided to test our device. The whole process should go like this: A button is pressed, it triggers the timer IC to send an input signal of a certain duration (around 6 to 7 seconds, a duration that can hydrate plants without drowning them), the relay module then receives this signal, and opens it ports, enabling electricity and power to go through the water pump allowing water to be siphoned out. If water is running short, the LED on top of the project housing should light up, indicating that a refill is needed. And to our relief, it worked.
Conclusion
this plant watering device with a water level indicator stands as a testament to the transformative power of applying theoretical knowledge to real-world applications. Our journey began with the foundational concepts of Discrete Structures, a subject that explores the building blocks of digital systems. However, the true learning came through the process of translating those concepts into a tangible device.
Our initial ambition to create a fully automated watering system proved to be beyond the limitations of using only integrated circuits. This initial setback, however, fostered a spirit of creative problem-solving. We pivoted to a semi-automatic design, requiring user interaction but still offering the benefits of timed watering and a low-water level indicator.
The project also highlighted the power of collaboration. As a group, we brainstormed ideas, researched solutions, and celebrated successes together. The online community’s willingness to share knowledge proved invaluable, reminding us of the importance of fostering a culture of open exchange in the pursuit of learning.
“Hakuna Matata! It means no worries for the rest of your days.” — Timon & Pumbaa (The Lion King)
