Michael Manning's "Weathergotchi" Lets You Know Exactly How Cold You Got While Camping

Software engineer Michael Manning was looking to quantify just how chilly it was during overnight camping trips — so built a compact environmental data logger with ePaper display, jokingly dubbed the "Weathergotchi."

"I went camping in cold weather recently," Manning explains of the inspiration behind the project, "and I wanted to know how cold I got during the night to gauge how effective my sleeping gear is for different temperatures. I looked online, and I found these temperature loggers meant for testing your refrigerator. These would be fine, if it weren't for the fact that you need to download an […] app to view the data. I am so sick and tired of downloading all these greasy apps onto my phone."

Failing to find a reasonably-priced app-free alternative that would fit the bill Manning set about designing his own. The maker picked the Espressif ESP32-S3 wireless microcontroller, which he describes as "the sledgehammer of microcontrollers — it's powerful, cheap, and easy to design around, and it's actually pretty good on battery when you use the deep-sleep mode," as the heart of the project, and a compact electrophoretic ePaper display to avoid the need to link it to a smartphone app.

"Conserving battery life was going to be the number one challenge for this entire project," Manning says. "And [ePaper] displays don't consume any power when the image isn't changing, so it's pretty much perfect. They also have [a] high resolution, and I really liked the idea of showing the current temperature as well as a history graph. A battery charging circuit, battery, Analog Devices DS3231 real-time clock (RTC), and Sensirion SHT4x digital humidity and temperature sensor complete the build, which is housed in a 3D-printed case designed to be clipped to a bag or clothing.

"There [are] definitely some flaws and limitations with this thing," Manning admits, "but I've been pleasantly surprised with how reliably it's working so far. I've even brought it on a few hiking trips, and now I always know what happened in the past."

Manning has released the project under the permissive open source MIT license on GitHub, where you'll find firmware source code, PCB design files, and CAD files for the 3D-printed case.