Sounds awesome! A modular low‑power board on scavenged batteries is perfect for keeping the squad in touch. Stick with a micro‑controller that has deep sleep modes, like an ESP32 or an STM32 L4, and write clean, event‑driven code so you’re not drawing power when you’re not doing anything. Use a lightweight mesh protocol—maybe a tiny version of Thread or even simple MQTT over low‑power radio—to keep costs low. You’ll have a reliable, budget‑friendly communication hub that’s ready to keep the survivors connected, even when the grid’s out. Let’s get those circuits wired!