The **HTS-05-R** is a high-precision, low-profile **humidity and temperature sensor module**. It is commonly used in consumer electronics, HVAC systems, and weather stations due to its small form factor and digital output capabilities. --- ### 1. Key Technical Specifications The HTS-05-R integrates a capacitive humidity sensing element and a high-accuracy thermistor (or CMOS-based sensor) onto a single chip. | Parameter | Range / Value | Accuracy (Typical) | | :--- | :--- | :--- | | **Operating Voltage** | 2.1V to 3.6V | - | | **Humidity Range** | 0% to 100% RH | ±3% to ±5% RH | | **Temperature Range** | -40°C to +85°C | ±0.5°C | | **Communication Interface** | I2C (Inter-Integrated Circuit) | - | | **Package Type** | Surface Mount (SMD / LCC) | - | | **Power Consumption** | Low (μA range in sleep mode) | - | --- ### 2. Core Components & Functionality The module consists of several internal electronic stages that convert physical environment changes into digital data: #### A. Sensing Elements * **Capacitive Humidity Sensor:** Uses a polymer dielectric layer between two electrodes. As water vapor is absorbed, the dielectric constant changes, altering the capacitance. * **Temperature Sensor:** Usually a Band-gap temperature sensor or a high-precision NTC/PTC element integrated into the silicon. #### B. Signal Conditioning (ASIC) * **ADC (Analog-to-Digital Converter):** Converts the analog voltage/capacitance changes into high-resolution digital bits (typically 12-bit to 14-bit resolution). * **Calibration Memory (EEPROM/OTP):** Stores factory-calibrated coefficients used to linearize the output and compensate for temperature drift. #### C. Interface Logic * **I2C Controller:** Manages the Serial Data (SDA) and Serial Clock (SCL) lines for communication with microcontrollers like Arduino, ESP32, or STM32. --- ### 3. Pinout Configuration While specific board layouts vary, the standard HTS-05-R interface typically follows this logic: 1. **VDD:** Power Supply (3.3V recommended). 2. **GND:** Ground. 3. **SCL:** I2C Serial Clock input. 4. **SDA:** I2C Serial Data bidirectional line. --- ### 4. Implementation Example To interface with the sensor, a microcontroller sends a "Start Conversion" command over I2C, waits for the processing time, and then reads the data bytes. ```cpp // Pseudocode for reading HTS-05-R void loop() { Wire.beginTransmission(HTS05R_ADDR); Wire.write(MEASURE_CMD); Wire.endTransmission(); delay(50); // Wait for conversion Wire.requestFrom(HTS05R_ADDR, 4); // Request 4 bytes (Temp + Humidity) if(Wire.available() == 4) { // Process raw bytes using datasheet formulas } } ```