For a forest node you’ll want something that stays in deep sleep most of the time and wakes for just a few seconds to read the sensor and transmit. A good pick is the nRF52832 or the STM32L0‑x; both have <1µA in standby, built‑in BLE or sub‑GHz radio, and plenty of low‑power peripherals. If you need more RAM or a richer stack, the ESP32‑S2 is a solid choice, but it draws a bit more when awake, so you’ll need a tighter duty cycle. Solar side: a 2‑3 W panel is enough if you place it on a small mount and feed it through a tiny buck‑boost or MPPT converter to a 3.7 V Li‑pol. The battery can be a 1‑2 Ah Li‑pol or a small supercap bank if you’re only running for a few minutes per day. Keep the charge controller low‑power; a simple MPPT IC like the MCP1640 or a DC‑DC step‑up with a sleep mode will do. Do a quick power budget: say 5 µA in sleep, 10 mA for 10 s a day, that’s about 10 mAh per day – a 2 Ah battery will last months if your panel is angled right. Just remember to keep the firmware lean: disable all peripherals you don’t use, put the MCU in sleep immediately after transmission, and keep the radio off until you need it. That way you’ll get a year of autonomous operation out of a single solar panel and battery.

Yeah, the enclosure is key—something like a polycarbonate case with a gasket and a small port for the panel. Keep the panel angled to the sun but out of reach of branches, maybe a rigid mast to keep it upright. And remember to add a small vent for heat; even a low‑power MCU can overheat if sealed too tight. Once you lock that down, the node will sit there like a silent sentinel.

Right, a 2‑mm slit is enough for air but big enough that a squirrel can’t fit. Just run a thin wire through it if you need a fan in the future, and add a little mesh over the slot. That keeps the internals cool without inviting critters. Happy building!

Sounds like a perfect little watchtower—just remember to put a tiny thermal cut‑off if you ever push the battery past 3.3 V, and you’ll have a quiet, critter‑proof node. Happy tinkering!