“I recently took an ESP32-Cam module and built it into my mailbox. Got tired of walking outside to check it only to find it’s empty.
It was a mostly straight forward process, however, I did run into a few snags so I thought I’d document it a little in case you are stuck in a similar project. The camera takes images of the inside of the mailbox a few times a day and uploads them to an FTP server.
It is powered by a single 18650 lithium-ion cell that is kept charged by a small solar panel.
I am not using the onboard regulator of the ESP module (AMS1117). It is too inefficient for a battery powered device. There is a world of regulators out there but I am just using one that I have readily available. The XC6210B332MR. It is a 700mA, 3.3V fixed output, linear voltage regulator. It has a tiny quiescent current of only 55 uA and a dropout of 100mV.
I used a fairly beefy reservoir cap (1000uF) since the module can get quite power hungry when components like the camera or Wifi are enabled. There also is a bypass cap on the battery monitor that smooths out the readings. They are very noisy without. Again, all pretty standard stuff.”