## Overview of the TSSP40 Series The **TSSP40** is a compact infrared (IR) sensor module designed specifically for **sensor applications** rather than traditional remote control data transmission. It is manufactured by Vishay Intertechnology and is commonly used for proximity sensing and light barriers. --- ### 1. Key Technical Specifications | Parameter | Value/Range | | :--- | :--- | | **Supply Voltage (Vcc)** | 2.5 V to 5.5 V | | **Supply Current (Is)** | 0.7 mA (typical) | | **Carrier Frequency** | 38 kHz or 56 kHz (model dependent) | | **Transmission Distance** | Up to 8 meters (with TSAL6200 emitter) | | **Output Type** | Active Low (Open Collector/Internal Pull-up) | | **Operating Temperature** | -25 °C to +85 °C | --- ### 2. Internal Electronic Architecture The TSSP40 integrates several electronic components into a single mold (epoxy package): 1. **Photo Diode:** A high-speed PIN photodiode that converts infrared light into electrical signals. 2. **Preamplifier:** Boosts the weak signal from the photodiode. 3. **Automatic Gain Control (AGC):** Stabilizes the signal in different ambient light conditions. 4. **Band Pass Filter:** Specifically tuned to the carrier frequency (e.g., 38 kHz) to reject noise from sunlight or fluorescent bulbs. 5. **Demodulator:** Converts the carrier signal into a simple binary logic level (High/Low). --- ### 3. Difference: TSSP vs. TSOP It is important to distinguish the **TSSP** series from the more common **TSOP** series: * **TSOP (Remote Control):** Designed to ignore continuous carrier waves to prevent noise. It requires "bursts" of data. * **TSSP (Sensing):** Designed to handle **continuous** carrier signals. This makes it ideal for: * **Proximity Sensing:** Detecting if an object reflects light back. * **Light Barriers:** Detecting if a beam is broken (e.g., in a doorway). --- ### 4. Basic Circuit Connection To use the TSSP40, a simple 3-pin setup is required. It is recommended to use an RC filter on the supply line to minimize power supply noise. ```cpp // Schematic Logic [VCC] --- [47 Ohm Resistor] ---+--- [Pin 3: Vs] | [4.7uF Capacitor] | [GND] -------------------------+--- [Pin 2: GND] [Pin 1: OUT] --- [To Microcontroller GPIO] ``` --- ### 5. Applications * **Reflective Sensors:** Used in automated faucets or soap dispensers. * **Beam Interrupters:** Used in counting items on a conveyor belt or garage door safety sensors. * **Distance Estimation:** When combined with PWM on the IR LED, it can be used for rough distance measurements.