Yeah, I’ve built a few of those. Start with a cheap MCU like the ESP32 or STM32, then add a solar panel that can give at least 2‑3 W. Put a charge controller in the middle, maybe a small battery like a 12 V lead‑acid or a lithium pack. Keep the firmware lean – just log the sensor data, timestamp, and push it when Wi‑Fi is available. Use a low‑power mode between samples so you don’t drain the battery. The trick is to size the panel and battery for the worst‑case daylight, and keep the code simple so it can run on a single core. I can show you the schematic if you need it.