Height meter on an Arduino Uno

// Height meter: a VL53L1X laser ranger looks straight down for the height
// above the floor, and a DPS310 barometer works out how far it has climbed
// from the change in air pressure, the way a drone keeps its height.
//
//   VL53L1X, DPS310   SDA -> A4   SCL -> A5   VIN -> 5 V   GND -> GND
//
// The laser is exact to a few millimeters but only reaches 4 m. The
// barometer reaches any height, but air pressure only falls about 12 Pa a
// meter near the ground, so it needs the DPS310's precision. Together they
// cover both.
//
// Things to try. Drag the distance slider on the VL53L1X. Then drag the
// pressure slider on the DPS310 down by 12 hPa: that is about 100 m of climb.

#include <Wire.h>
#include <VL53L1X.h>
#include <Adafruit_DPS310.h>

VL53L1X ranger;
Adafruit_DPS310 baro;
float startPressure = 0;

void setup() {
  Serial.begin(9600);
  Wire.begin();
  ranger.setTimeout(500);
  if (!ranger.init()) {
    Serial.println("No VL53L1X");
  }
  ranger.setDistanceMode(VL53L1X::Long);
  ranger.setMeasurementTimingBudget(50000);
  ranger.startContinuous(100);
  if (!baro.begin_I2C(0x76)) {
    Serial.println("No DPS310");
  }
  baro.configurePressure(DPS310_16HZ, DPS310_16SAMPLES);
  baro.configureTemperature(DPS310_16HZ, DPS310_16SAMPLES);
  // Throw away the reading taken at the old settings, then wait for the
  // first at the new ones.
  sensors_event_t temp, pressure;
  baro.getEvents(&temp, &pressure);
  while (!baro.temperatureAvailable() || !baro.pressureAvailable()) {
    delay(10);
  }
  baro.getEvents(&temp, &pressure);
  startPressure = pressure.pressure;
  Serial.println("Height meter ready");
}

void loop() {
  uint16_t mm = ranger.read();
  sensors_event_t temp, pressure;
  baro.getEvents(&temp, &pressure);
  // About 8.3 m of height for each hectopascal near sea level.
  float climbed = (startPressure - pressure.pressure) * 8.3;

  Serial.print("floor ");
  if (ranger.ranging_data.range_status == VL53L1X::RangeValid) {
    Serial.print(mm);
    Serial.print(" mm");
  } else {
    Serial.print("out of range");
  }
  Serial.print("  climbed ");
  Serial.print(climbed, 1);
  Serial.println(" m");
  delay(400);
}