Mailbox Sensor

Well... after a couple more weeks my 6-AA batteries still proved to be insufficient to keep powering the ESP32 (or at least enough to power up the WiFi). It's been chilly here, but barely below freezing at night, so temperature clearly isn't the culprit this time (or at least not the main one). Considering that it's in deep-sleep all the time, except for about 30 seconds every day, it seems that my power calculations were WAY off. My best guess is that the voltage regulator on the development board burns a LOT of power (well, lots is relative depending on your power source), and hence the order of magnitude less battery time I'm seeing. Fortunately, it dawned on me a few weeks ago that my mailbox is on an exterior wall that happens be be directly behind my washer/dryer AND there also happens to be a free outlet right there as well. It feels quite silly to say, but I just got done drilling a small hole through the exterior of my house so I could run a USB cable into my mailbox (and yes, I caulked it on both sides).

Not quite as satisfying as getting it all running on batteries, but now I won't ever have to deal with them either. Win some, lose some.

Well, this might set a record for the shortest working project that I thought was 'done'. Turns out AA batteries drop in voltage when cold a lot more than I expected. After some very mild cold weather (barely below freezing), the voltage dropped enough that the ESP32 wasn't able to fully boot/connect to Wi-Fi on being woken up. Obviously there are much more elegant ways to handle it, but based on what I had on hand I decided to just double the number of AA batteries I use (yes, I realize how excessive it is using 6xAA batteries to power such a simple and small device). Size of the finished project isn't really an issue, and presumably the extra voltage should mean I can eek out every bit of juice out of the batteries now. My only real concern is whether the loss from the voltage regulator on the board will start adding up more. Time will tell...