The first step is always research. I knew what the problem was, but I needed to figure out which technology I wanted to use. So I went to MIT’s Material Science Department page, where I learned that carbon nanotubes can be used to detect gases. They had so many videos and pictures that I could actually visualize what they were talking about. And I thought if they could detect gases, maybe they could be used to detect lead in water.
I started to put ideas together and had to figure out how to make it react to lead so that there would be a change in the flow of electrons. Then there was the question of how to have it to display. Did I want it to light up a red, yellow, or green LED or did I want to send it off to a mobile phone? And then finally I started to think about the user experience. Clearly a user wouldn’t want a box with electronics on the outside, so I knew I wanted a compact container and came up with the idea for a cartridge.