Implementing adaptive sleep intervals for battery-powered LoRa sensor node based on transmission urgency

Question

I'm working on a battery-powered environmental monitoring system using an Arduino Nano 33 IoT with a LoRa module (RFM95W). I need to implement an adaptive sleep interval algorithm that adjusts based on sensor reading variations. Currently, my code uses fixed intervals:

void loop() {
  float currentTemp = readTemperature();
  float currentHumidity = readHumidity();
  
  sendLoRaData(currentTemp, currentHumidity);
  LowPower.deepSleep(SLEEP_INTERVAL);  // Fixed 15-minute interval
}

How can I modify this to implement dynamic sleep intervals that:

• Decrease sleep time when sensor readings show significant changes
• Increase sleep time during stable periods
• Consider battery level in the decision
• Maintain a maximum sleep time of 30 minutes
• Ensure critical alerts are still sent immediately

I've tried using simple thresholds, but this leads to frequent wake-ups during minor fluctuations. What would be an efficient algorithm for this?

I implemented this approaches to solve this:

• Simple threshold-based:

const float TEMP_THRESHOLD = 0.5;  // Celsius
const float HUMIDITY_THRESHOLD = 2.0;  // Percent
unsigned long calculateSleepTime() {
    float tempDiff = abs(currentTemp - lastTemp);
    float humDiff = abs(currentHumidity - lastHumidity);
    
    if (tempDiff > TEMP_THRESHOLD || humDiff > HUMIDITY_THRESHOLD) {
        return MIN_SLEEP_TIME;  // 5 minutes
    }
    return MAX_SLEEP_TIME;  // 30 minutes
}

This led to frequent wake-ups due to normal sensor noise.