SGP40 VOC Sensor with a Raspberry Pi Pico

// SGP40 VOC Sensor on Raspberry Pi Pico: wiring and a free simulation at https://www.tinkered.ai/components/sgp40-voc-sensor/raspberry-pi-pico
#include <Wire.h>
#include "Adafruit_SGP40.h"

Adafruit_SGP40 sgp;

// The SGP40 compensates for humidity and temperature. With no sensor for them, pass the
// library's defaults, 25 °C and 50 %RH; with an SHT4x or a BME280 beside it, pass its readings.
const float TEMPERATURE_C = 25.0;
const float HUMIDITY_RH = 50.0;

void setup() {
  Serial.begin(115200);
  if (!sgp.begin()) {                 // fixed I2C address 0x59
    Serial.println("SGP40 not found");
    while (1) delay(10);
  }
  Serial.println("SGP40 ready: the VOC Index reads 0 for its first 45 s");
}

uint32_t lastSample = 0;

void loop() {
  // Sensirion's VOC algorithm expects one sample a second. The library waits about 250 ms
  // for each measurement, so time the loop with millis() rather than delay(1000).
  if (millis() - lastSample < 1000) return;
  lastSample = millis();
  // Both calls take (temperature, humidity), in that order. measureVocIndex() measures and runs
  // the algorithm: 100 is this air's recent average, higher means more VOCs than usual, lower fewer.
  int32_t vocIndex = sgp.measureVocIndex(TEMPERATURE_C, HUMIDITY_RH);
  Serial.print("VOC Index: ");
  Serial.println(vocIndex);
}