// Drop into any ESP32/Arduino sketch — works on all EmberSignal-compatible boards
void encodeEmberPayload(uint8_t *buf,
                         float temp_c, float rh_pct,
                         float pm25,   float wind_kmh,
                         uint16_t voc_ppb, uint8_t battery_pct) {
  int16_t  t = (int16_t) (temp_c   * 10.0f);
  uint16_t h = (uint16_t)(rh_pct   * 10.0f);
  uint16_t p = (uint16_t)(pm25     * 10.0f);
  uint16_t w = (uint16_t)(wind_kmh * 10.0f);
  buf[0]=t&0xFF;  buf[1]=t>>8;
  buf[2]=h&0xFF;  buf[3]=h>>8;
  buf[4]=p&0xFF;  buf[5]=p>>8;
  buf[6]=w&0xFF;  buf[7]=w>>8;
  buf[8]=voc_ppb&0xFF; buf[9]=voc_ppb>>8;
  buf[10]=battery_pct;
}