7Semi STS3x Arduino Library

Arduino driver for the STS3x digital temperature sensor.

The STS3x is a high-accuracy digital temperature sensor from Sensirion featuring an I²C interface, fast response time, and high measurement precision. It is designed for applications such as environmental monitoring, industrial control systems, and IoT sensing devices.

This library provides a simple interface for configuring the sensor and reading temperature values in degrees Celsius.

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Features

• High accuracy temperature measurement
• Single-shot measurement mode
• Periodic measurement mode
• Configurable measurement repeatability
• Configurable measurement rate
• Status register reading
• Sensor soft reset
• CRC data validation for reliable communication

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Supported Platforms

• Arduino UNO / Mega
• ESP32
• ESP8266
• Any board supporting the Wire (I²C) library

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Hardware

Supported sensor:

7Semi Digital Temperature Sensor I2C Breakout – STS3x

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Connection

The STS3x communicates using I²C.

I²C Connection

STS3x Pin	MCU Pin	Description
VCC	3.3V	Sensor power
GND	GND	Ground
SCL	SCL	I²C clock
SDA	SDA	I²C data

I²C Notes

Default sensor address: 0x4A

Recommended I²C speed: 100 kHz – 400 kHz

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Installation

Arduino Library Manager

1. Open Arduino IDE
2. Go to Library Manager
3. Search for 7Semi STS3x
4. Click Install

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Manual Installation

1. Download this repository as ZIP
2. Arduino IDE → Sketch → Include Library → Add .ZIP Library

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Example

#include <7Semi_STS3x.h>

STS3x_7Semi sensor;

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

  if(!sensor.begin())
  {
    Serial.println("STS3x not detected");
    while(1);
  }
}

void loop()
{
  float temperature;

  temperature = sensor.readTemperature();

  Serial.print("Temperature: ");
  Serial.print(temperature);
  Serial.println(" C");

  delay(1000);
}

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## Library Overview
### Reading Temperature
```cpp
float temperature;

temperature = sensor.readTemperature();

Serial.print("Temperature: ");
Serial.println(temperature);

Returns the measured temperature in degrees Celsius.

Single Shot Measurement

float temperature;

sensor.measureSingleShot(REPEATABILITY_HIGH, false, temperature);

Parameters:

• Repeatability – Measurement precision level

• Clock stretching – Enable or disable clock stretching

Repeatability options:

REPEATABILITY_LOW
REPEATABILITY_MEDIUM
REPEATABILITY_HIGH

Periodic Measurement

sensor.startPeriodicMeasurement(REPEATABILITY_HIGH, MPS_2);

float temperature;

sensor.blockingReadMeasurement(temperature);

Measurement rates:

MPS_0_5
MPS_1
MPS_2
MPS_4
MPS_10

These correspond to measurements per second.

Sensor Status

The sensor status register can be read for debugging and system monitoring.

uint16_t status;

sensor.readStatusRegister(status);

Serial.print("Status: ");
Serial.println(status, HEX);

The status register contains flags for:

• Alert pending

• Heater status

• Temperature tracking alerts

• Reset detection

• Command errors

• Write checksum errors

Sensor Reset

This performs a sensor soft reset and clears the internal state machine.

sensor.softReset();

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Example Applications

Typical applications include:

• Environmental temperature monitoring

• Industrial control systems

• IoT sensing devices

• Data logging systems

• HVAC systems

• Smart home monitoring

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License

MIT License

Author

7Semi