“Although you can buy analog tide clocks that have a single hand indicating whether the tide is high or low or somewhere in between, what I wanted was something that would tell me at what time low tide will be. I wanted something I could glance at quickly without having to turn it on, or push any buttons, or wait. And I wanted something with long battery life. So I used a TTGO T5 board, which is an ESP32-based board with a 2.13” e-paper display, connected to a TTL5110 chip. The TPL5110 turns on the T5 every 2.5 hours, and once a day the T5 downloads tide data from NOAA and weather data from OpenWeatherMap, displays the data on the e-paper, then tells the TPL5110 to turn the T5 off.”