Hey! Sounds like you’re chasing some sweet aerial secrets. For the sensor stack, keep it simple: start with a high‑resolution LIDAR for the fine topography, add an infrared camera for thermal mapping at dusk, and slap on a low‑frequency sonar just in case the valleys have some subterranean trickery. If you’re tight on weight, swap the LIDAR for a solid‑state one—it’s lighter and still gives good range. If you need a hack, try pairing the LIDAR data with your GPS for real‑time triangulation; that way you can auto‑adjust the flight path on the fly. Need help wiring or firmware tweaks? I’ve got a spare microcontroller and some firmware snippets that might just do the trick. Let me know where you’re stuck and we’ll dive in!

Here’s a quick snippet in C for a simple GPS triangulation loop—just plug it into your microcontroller’s main file: ```c #include <GPS.h> #include <Wire.h> GPS gps; // Assume you have a GPS library float lastLat, lastLon; unsigned long lastTime; void setup() { Serial.begin(115200); gps.begin(); lastTime = millis(); } void loop() { if (gps.available()) { float lat = gps.latitude(); float lon = gps.longitude(); unsigned long now = millis(); float deltaTime = (now - lastTime) / 1000.0; // seconds float deltaLat = lat - lastLat; float deltaLon = lon - lastLon; // Simple distance in meters (rough) float distance = sqrt(deltaLat*deltaLat + deltaLon*deltaLon) * 111320.0; float speed = distance / deltaTime; // m/s Serial.print("Speed: "); Serial.print(speed); Serial.println(" m/s"); lastLat = lat; lastLon = lon; lastTime = now; } } ``` Power‑saving tips: 1. Put the LIDAR and sonar into sleep mode when you’re above the valley—wake them only when you’re getting into the mapping zone. 2. Use a buck‑converter instead of a linear regulator; that saves a ton of heat and energy. 3. Keep the GPS running on a low‑frequency update (like 1 Hz) instead of 10 Hz unless you need real‑time speed. 4. Add a small capacitor at the GPS module’s Vcc to smooth out transient spikes. 5. If the microcontroller supports it, run the processor in a low‑power core mode when you’re just collecting data. Let me know if you hit any snags—happy to tweak the code further!

Here’s a quick sleep routine you can drop in. I’m assuming you’re using a typical microcontroller with an RTC pin for the interrupt. ```c // Put LIDAR/sonar into low‑power mode void sensorSleep() { digitalWrite(LIDAR_EN_PIN, LOW); // power‑down LIDAR digitalWrite(SONAR_EN_PIN, LOW); // power‑down sonar // Disable ADC channels if you’re using them } // Wake‑up when the plane is in the valley void sensorWake() { digitalWrite(LIDAR_EN_PIN, HIGH); digitalWrite(SONAR_EN_PIN, HIGH); } // Set up the interrupt: when the GPS reports a latitude change > 0.001°, // consider that a valley entry void setupInterrupt() { attachInterrupt(digitalPinToInterrupt(VALLEY_DETECT_PIN), sensorWake, RISING); } // In loop() you just keep the sensors sleeping most of the time void loop() { sensorSleep(); // keep them asleep delay(1000); // 1 second sleep cycles // When the interrupt fires, sensorWake() runs automatically } ``` Battery specs: a 3‑cell Li‑Po pack (11.1 V) around 5000 mAh is a good middle ground. With the buck converter you’ll get about 10 – 12 W of power at peak (LIDAR, sonar, GPS, MCU). That’s enough for a 30‑minute high‑resolution run and still leaves a cushion for unexpected power spikes. If you go for a 4‑cell pack, you’ll double the runtime but you’ll need to keep an eye on the voltage regulator’s input range. Happy hacking, and keep those valleys quiet!

Sounds like a solid plan—your valley mission should fly smooth. If anything hiccups, just ping me. Happy mapping!