This project started when our teacher complained about the difficulty of watering his hanging plants at the back of the class. His process entailed moving a ladder through a narrow cluster of tables and past fragile projects, filling a bucket of water, and carrying it up the ladder. Our group saw this inconvenience and decided to dedicate our project work to making the watering easy.

We decided to take a look into “Fun Theory”, the idea that fun can be a core element (not just a minor improvement) of a successful product. We felt that, after some brainstorming, the most practical “Fun Theory” idea would be to devise a train that would deliver water.

Originally, we had thought to have the track go around the entirety of the classroom. It would provide something interesting to look at, especially when in action. In addition, it would obviously serve a very useful function. In our first thoughts about wrapping the track around the walls, we had thought that having the train descend to a lower height for someone to fill up would be beneficial, but we soon realized that it would take a tremendous amount of power to get the train to climb any slope, much less one the size that we were considering. We then realized that the pump system we had thought of in the more practical iteration could actually serve a purpose in this project.

With that in mind, we set out to create a train system that would be filled up using the pump system, with a bucket on the ground or countertop that could be easily filled. We understood that we would have to find a way to stop the train at the right time to somehow fill it up, and we would need to find a way to store water on a train car. With that in mind, we set out to 3D print a structure that would be able to contain water. Starting with a closed box, we realized that an open container with lips facing inward would both successfully carry the water, as well as keep it from splashing out too much when the train was in motion, or accelerating.

While in the process of printing a holding container, we laser cut new train tracks, as we saw that the easiest and least expensive way to hang track from the ceiling. We originally planned that wooden tracks would be suspended through wires from holes cut in the track to the metal support structures in the ceiling of the school. We later realized that, with the short amount of time we had, we should focus on the train itself.  The laser cut track seemed to work well, however, and we would use it if installing a large system.

What we focused on next was how to stop, and how to decelerate the train on the way in to a Refill Station, or a Plant Station. At first, we found it sensible to use some sort of a “button” that the train would hit as it got close to a station. Of course, it was the rudimentary definition of an electrical button, but it would hopefully do the trick. We thought of having two wires poking out from the sides of the train. When the wires would come in contact with the “switch”, likely a piece of wire or tinfoil, a current would flow, and the train stop would be triggered. We later worried that the constant hitting of the wires might result in the wires bending in ways we wouldn't want. In addition, we thought the train might overrun the switch and keep going. In response to this, we decided the best form of switch would be a distance detector.

Even with our distance sensors, we often found trouble. First off, much of the distance sensors’ software required relatively complicated coding with the Arduino microcontroller, something of which we only had basic knowledge. Second, the distance sensors would often give false reads and triggers, as slight motion or a distance change would set them off, or in some cases, the something would trigger the sensor, and it wouldn't go off. Third, the way we had attached the sensor on the train (angled slightly up and forward) allowed it to read other objects that we did not want it to sense, such as supporting structures, the incoming water tube at the Refill Station, or even nearby bystanders.This issue was easily fixed by adjusting the sensor perpendicular the train and pointing it straight up.

The most difficult issues we had on the train were with timing and the coding. Again, with our rudimentary knowledge of Arduino, we fund it very difficult to code for filling stops, and other variables, such as when to slow down, and how long the pump would draw water for. Luckily, with lots of help from Mr. Moody, we fixed many kinks and the bugs in the programming, and got both our onboard and external Arduinos and sensors running smoothly.

During the last few days of the build, we had realized that the train had started to slow down. We first believed that this was because the batteries were dying, but this proved not to be the case. Second, we thought that the train may be too heavy with water included, and that the battery was struggling to output enough power to the Arduino, pump, and motor. What we later realized was that we had the battery wired directly to the Arduino (5V output, compared to a 7.4 that we wanted), and easily connected new Lithium batteries to power the motor.

The final iteration to the project occurred during our expo day. During the expo, we had started to notice the train struggling to get around the curves. This issue would gradually become more prominent as time passed, with all of us having to assist the train in getting around the turns. After a battery replacement, we found that the train was still struggling to make it around. We then came up with the idea to use not one, but two 8 ohm resistors in parallel to cut the resistance in half and increase the power to the train motor.  (With no resistor, the train would travel way too fast and far overrun the Refill and Plant stations). We found that the addition of another resistor actually made the train more reliable in stopping at the right place, as well as making it around the two major curves of our track.

Overall, response from the Oasis Rail System was very positive, as many saw it as a great product for those looking to simplify life, have a little fun, and maybe even appeal to children. Optimally, we would sell it as a kit designed around programming for kids.  It seemed that Oasis was a terrific balance of fun and practicality that makes a project great.