Light Length

My first version of LightLength with one transmitting node and one receiving node.

In my Junior year of high school, I worked on a device that would wirelessly measure distances using radio waves. I worked through two versions of this device and presented it during my school’s science fair. This was the first time I programmed an Arduino and admittedly I was a bit out of my depth. My general approach was to use two Arduinos to track how long it would take for a radio signal to travel from one node to another.

In my first prototype, I had one Arduino send a signal and the other receive it. Then I would have the receiving Arduino multiply the time it took for a signal to travel by the speed of light to obtain the distance. This approach assumed my Arduinos had very precise clocks that could capture the time it took for light to travel just a few centimeters. It also assumed that light travels at exactly the speed of light through the air and my Arduinos had perfectly synchronized clocks. Although all these assumptions made calculations easy, they were far from reality and my device would measure millions of kilometers rather than a few centimeters.

Light Length V2

My second version of LightLength, which used two transceiver nodes

My second version used a transceiver rather than a transmitter-receiver combination. This prototype created two-way communication between my nodes, whereas the first prototype had one-way communication. Unlike the first prototype, the nodes were constantly sending pings to each other to measure distances. One of the Arduinos would keep track of these measured distances and output a moving average. Theoretically, this meant that the longer the two nodes were in the same position, the more accurate the measurements became. However, This prototype relied on whatever Arduino libraries were pre-coded with the transceivers. These libraries may have had delays in them for the sake of maintaining a stable communication protocol. So, my device would still measure obscenely large distances. However, this was still an improvement over the original design since the distances were technically more accurate and more precise. Although I wasn’t successful, I developed a foundational understanding of microcontrollers and coding with Arduinos. I presented my findings in a technical report for the science fair, which you can download below.

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