“sustainability. In November, we’d installed three thousand sensors at wells across Ethiopia—no small feat, considering we had to make them ourselves. In the last three years, we’d built numerous prototypes and ended up with several duds. The challenge was unique: Our sensor needed to be made of UV-resistant, food-grade plastic that was durable enough to sit out in the open blazing sun and not get broken by people or animals. It had to measure chaotic water flow—not just water going evenly through a pipe, but water splashing up and around. And the batteries needed to last ten years without having to be changed. Most important, our sensor had to reliably transmit to us all the data it was collecting. So, we specially sourced a universal SIM card from a start-up in Hong Kong that had preexisting roaming agreements with every telecom company in the world—that way, the SIM card could work wherever we installed it. But when we tested our first prototype in Harrison, Scott. Thirst: A Story of Redemption, Compassion, and a Mission to Bring Clean Water to the World (pp. 288-289). The Crown Publishing Group. Kindle Edition. Harrison, Scott. Thirst: A Story of Redemption, Compassion, and a Mission to Bring Clean Water to the World (p. 288). The Crown Publishing Group. Kindle Edition. ”
