The **HAP-D1-R** is an ultra-miniature, high-sensitivity thermal infrared sensor module, typically utilized for non-contact temperature measurement. It is widely known for its integration in consumer electronics like smartphones (notably the Blackview rugged phone series) and IoT devices. --- ### ## Technical Specifications Overview The HAP-D1-R is a Thermopile-based sensor. Below are the core electronic characteristics: | Parameter | Specification | | :--- | :--- | | **Sensor Type** | Thermopile (Non-contact Infrared) | | **Operating Voltage** | 2.6V to 3.6V | | **Interface** | I2C (Inter-Integrated Circuit) | | **Object Temp Range** | -20°C to +100°C (Standard range) | | **Accuracy** | ±2°C to ±3°C (Depending on calibration) | | **Package Size** | Ultra-small (Approx. 3.2 x 3.2 x 1.45 mm) | --- ### ### Key Electronic Components The HAP-D1-R is not just a raw sensor; it is a **System-in-Package (SiP)**. It contains three main internal stages: 1. **Thermopile Die:** * Consists of a series of thermocouples connected in series. * Converts incoming infrared radiation from an object into a tiny micro-volt ($\mu V$) signal. 2. **Low-Noise Amplifier (LNA) & ADC:** * Because the voltage generated by the thermopile is extremely weak, an internal ASIC (Application-Specific Integrated Circuit) amplifies the signal. * A high-resolution Delta-Sigma ADC converts the analog signal into digital data. 3. **Thermistor (Reference):** * Measures the "Ambient Temperature" (the temperature of the sensor itself). * This is critical because the infrared reading is relative; the electronic controller uses this reference to calculate the absolute temperature of the target object. --- ### ### Pinout and Integration For electronic hobbyists or engineers integrating this into a circuit, the module typically follows a standard I2C wiring schema: * **VDD:** Power supply (3.3V typical). * **GND:** Common ground. * **SCL:** Serial Clock for I2C communication. * **SDA:** Serial Data for I2C communication. --- ### ### Operational Principles The sensor electronics function based on the **Stefan-Boltzmann Law**. The HAP-D1-R detects the intensity of infrared energy at specific wavelengths (usually 8-14 $\mu m$). ```c // Example Pseudocode for reading the HAP-D1-R via I2C void readSensor() { Wire.beginTransmission(HAP_D1_R_ADDRESS); Wire.write(DATA_REG_START); Wire.endTransmission(); Wire.requestFrom(HAP_D1_R_ADDRESS, 2); int rawData = (Wire.read() << 8) | Wire.read(); // Formula for conversion based on manufacturer datasheet float temperature = convertToCelsius(rawData); } ```