Reflection on the experimentation process

By Steve Wang

The sun, with its radiant warmth and life-giving energy, is an integral part of our daily existence. Its golden rays can uplift our spirits and bestow upon us a healthy dose of vitamin D. However, hidden within this celestial embrace lies an invisible danger: ultraviolet (UV) radiation. As we get exposed to more and more of it, we need to understand that there are potential health risks from overexposure to UV radiation. One of the most effective ways to combat this is to seek shelter. Some people do this very well by using umbrellas in high UV radiation conditions, but how effective is this method of protection? How does this method of shelter fare against different conditions we may face? This report will document the journey of attempting to answer this question, including the tools we used, the issues we encountered, and the conclusions we managed to draw from the experiments conducted.

To test how effective umbrellas are against UV radiation, we first need a UV sensor and many types of real-world conditions. For the real-world conditions, tests were run in different locations and at different times. For the UV sensor, we needed one that could constantly record the current UV index and be able to store the readings. So, we opted for the UV sensor called GUVA-S12SD UV Sensor Module which we connected to an Arduino UNO. We then connected the Arduino to laptops.

In theory, the UV sensor setup would work, but because it had to be portable and durable, it made the task more difficult. The Arduino did not have soldering joints to which the UV sensor could be directly soldered. To work around that issue, we soldered wires from the UV sensor to a circuit board, which we then drilled holes and screwed onto the screw holes on the Arduino. We then packed the whole thing into a box to protect it and make it portable. The end product looked something like this:

To retrieve the sensor values, we used a JavaScript library called Johnny-Five after compiling the standard Firmata code into the Arduino. We also implemented our custom code, which we refined over many versions. When the code receives the input, it will find a file to output the data and start recording for a specified amount of time. This process can be stopped and restarted at any time. Over multiple versions, this process was improved to make things easier. For example, in the latest version, the code can start all the sensors automatically, differentiate between multiple Arduinos, and have the ability to use multiple Arduinos on one laptop.

We then decided that we were ready to go and record data. After observing the data, we realized that the UV sensor we bought was defective and maxed out at less than 1 UV index. It was so bad that we could max it out with a phone flashlight. We are currently working on calibrating our sensors so that we will be able to record UV indexes accurately. Due to our failure to identify the issues with the sensor, no conclusions can be made about how well umbrellas act as protection from UV radiation. In the future, if we manage to get the UV sensors working, the effectiveness of umbrellas for UV protection can be tested by visiting multiple locations and conducting two tests at each location. One test will involve using an umbrella, while the other test will be conducted without an umbrella. Conducting multiple tests will demonstrate the effectiveness of umbrellas in providing UV protection.