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AGS10 TVOC Gas Sensor

The AGS10 is a digital TVOC gas sensor for measuring the total amount of volatile organic compounds (TVOCs) in the air. It is suitable for applications such as indoor air quality monitoring, smart home systems, and IoT projects.

Overview

  • Measured quantity: TVOC (Total Volatile Organic Compounds)
  • Interface: I²C
  • Supply voltage: 3.3 – 5.0 V
  • Logic level (I²C): compatible with 3.3 V and 5 V
  • I²C pull-ups: available on the breakout board
  • Output: TVOC value in ppb
  • Warm-up time: approx. 2–3 minutes

Typical Applications

  • Indoor air quality measurement
  • Smart home & building automation
  • Air monitoring in offices & workshops
  • Maker & IoT projects

Technical Data

Parameter Value
Measurement range 0 – 1000 ppb TVOC
Resolution 1 ppb
Interface I²C
I²C address 0x1A (default)
Supply voltage 3.3 – 5.0 V
Logic level 3.3 V / 5 V tolerant
Current consumption typically approx. 30 mA
Operating temperature -10 °C to +50 °C

Pinout & Connections

Pin Name Description
VCC Supply 3.3 – 5.0 V
GND Ground Ground
SDA I²C Data I²C data line
SCL I²C Clock I²C clock line

Note:
The I²C pull-up resistors are already integrated on the breakout board used.
Therefore, the sensor can be connected directly to 3.3 V or 5 V I²C buses.

Electrical Characteristics

  • Operation with 3.3 V or 5 V supply voltage
  • I²C logic levels compatible with 3.3 V and 5 V
  • Internal level adaptation via the breakout board
  • Stable quiescent current after warm-up phase

Communication (I²C)

  • Bus: I²C
  • Address: 0x1A
  • Pull-ups: available on the board
  • Data format: 16-bit TVOC value (ppb)

Reading a measurement (simplified)

  1. Start condition
  2. I²C address + read
  3. Receive 2 bytes
  4. Calculate TVOC value

Example Code

Arduino (I²C)

## Beispielcode (Arduino)


#include <Wire.h>

#define AGS10_ADDR 0x1A
#define REG_DATA_ACQ        0x00
#define REG_READ_VERSION    0x11
#define REG_READ_RESISTANCE 0x20
#define CMD_DELAY_MS        30
#define READ_DELAY_MS       1500

uint8_t calcCRC8(const uint8_t *data, uint8_t len) {
  uint8_t crc = 0xFF;
  for (uint8_t b = 0; b < len; b++) {
    crc ^= data[b];
    for (uint8_t i = 0; i < 8; i++)
      crc = (crc & 0x80) ? (crc << 1) ^ 0x31 : (crc << 1);
  }
  return crc;
}

bool i2cRead5(uint8_t reg, uint8_t *out) {
  Wire.beginTransmission(AGS10_ADDR);
  Wire.write(reg);
  if (Wire.endTransmission() != 0) return false;
  delay(CMD_DELAY_MS);

  if (Wire.requestFrom((int)AGS10_ADDR, 5) != 5) return false;
  for (uint8_t i = 0; i < 5; i++) out[i] = Wire.read();

  return (calcCRC8(out, 4) == out[4]);
}

bool readTVOC(uint32_t &tvoc, uint8_t &status) {
  uint8_t buf[5];
  if (!i2cRead5(REG_DATA_ACQ, buf)) return false;

  status = buf[0];
  tvoc = ((uint32_t)buf[1] << 16) | ((uint32_t)buf[2] << 8) | buf[3];
  delay(READ_DELAY_MS);
  return true;
}

bool readVersion(uint8_t &ver) {
  uint8_t buf[5];
  if (!i2cRead5(REG_READ_VERSION, buf)) return false;
  ver = buf[3];
  return true;
}

bool readResistance(uint32_t &res) {
  uint8_t buf[5];
  if (!i2cRead5(REG_READ_RESISTANCE, buf)) return false;
  res = ((uint32_t)buf[1] << 16) | ((uint32_t)buf[2] << 8) | buf[3];
  return true;
}

void setup() {
  Serial.begin(115200);
  Wire.begin();

  Serial.println("Paradisetronic - AGS10 TVOC Sensor Test");
  Serial.println("Bitte mindestens 2 Minuten Vorheizzeit beachten...");
  delay(2000);

  uint8_t fw;
  if (readVersion(fw)) {
    Serial.print("Firmware-Version: 0x");
    Serial.println(fw, HEX);
  }

  uint32_t r;
  if (readResistance(r)) {
    Serial.print("Sensor-Widerstand: ");
    Serial.print(r / 10.0, 1);
    Serial.println(" kOhm");
  }

  Serial.println("Starte TVOC-Messung...");
}

void loop() {
  uint32_t tvoc;
  uint8_t status;

  if (readTVOC(tvoc, status)) {
    Serial.print("Status: 0x");
    Serial.print(status, HEX);
    Serial.print(" | TVOC: ");
    Serial.print(tvoc);
    Serial.println(" ppb");
  } else {
    Serial.println("Fehler beim Lesen der TVOC-Daten.");
  }

  delay(2000);
}

Calibration & Notes

  • After power-up, a warm-up time of approximately 2–3 minutes is required before stable measurements are available.
  • The TVOC measurement is relative and intended for trend and comparison analysis, not as a laboratory-grade reference.
  • For meaningful results, the sensor should be initialized in clean reference air.
  • Sudden changes in air composition (e.g. alcohol, cleaning agents, solvents) will cause significantly increased readings.
  • The sensor is not suitable for safety-critical applications (e.g. gas alarm or warning systems).

Troubleshooting

No I²C communication

  • Ensure SDA and SCL are connected correctly
  • Check the supply voltage (3.3 V or 5 V)
  • No external I²C pull-up resistors are required (already present on the board)
  • Verify the I²C address (0x1A)
  • Test the I²C bus using an I²C scanner if necessary

Downloads

  • Datasheet (PDF)
  • Manufacturer documentation
  • I²C specification
  • Indoor air quality guidelines (TVOC)

Revision / Changelog

Version Date Change
1.0 2025-01-08 Initial release