Data-Driven Backpacking

As the old saying goes, you can’t take it with you. This wisdom is normally pulled out when discussing much weightier matters, but it also applies to backpacking. There is only so much gear you can cram into a backpack before it becomes unmanageable. Yet if you are going to be out in the wilderness for an extended period of time, you will need a lot of equipment.

A software engineer named Michael Manning has struggled with this problem many times, and decided to do something about it. His plan was to collect data that would help him to more intelligently pack his bag. After all, if you misjudge your needs, you could be carrying around unnecessary weight while missing the things you really do need.

In particular, Manning wanted to be sure that he brought along the right sleeping bag. To make sure it is appropriate for the temperature, he built a custom climate logger that records the outside temperature throughout the night. That allows Manning to compare how comfortable he felt in a particular sleeping bag given the outside temperature.

Plugging in to the grid isn’t exactly an option while backpacking, so Manning designed the device to be highly energy efficient. A custom circuit board was designed and populated with an ESP32-S3 microcontroller. A SHT45 temperature and humidity sensor was included to collect environmental data, and a DS3231 real-time clock timestamps the data and also wakes the ESP32 every minute from a deep sleep mode that conserves power.

For readout, a Waveshare 1.54-inch E Ink display module was selected. Because of this choice, the logger is able to get by with a small 400 mAh rechargeable battery and still have enough juice to keep on kicking for a full week.

To keep things as small as possible, Manning wrote a custom driver for the display rather than packing a separate driver board into the case. Speaking of the case, it was 3D-printed with tight clearances to hold the components via mechanical retention. There is no mention of weatherproofing, so it is unclear how well the logger might stand up to rain or other inclement weather.

Manning has not yet decided if the design will be fully open-sourced, so for now you will have to go by the relatively scant details available if you want to reproduce the project. It is not an especially challenging build, however, so that may not be too much of a problem. Check out the full project write-up for more details and inspiration.