These sensor modules are based on Vishay's TSSP77038 modulated infrared receivers. Unlike most IR receiver modules designed for remote control of appliances like televisions, the TSSP77038 has a fixed gain (sensitivity) that makes the sensor more predictable when used in proximity or reflectance sensors. The Pololu carrier module combines the TSSP77038 with an IR LED driven by a 555 timer-based circuit to make a complete sensor module that requires only a 3.3 V to 5 V power connection. An enable input allows control of whether or not the IR LED is on, and a digital output indicates whether or not an object is detected. The module is available in low-brightness and high-brightness versions, which provide detection ranges of up to approximately 12 inches (30 cm) and 24 inches (60 cm), respectively. The actual performance depends on many factors, including object size, reflectivity, and ambient lighting conditions.

We carry several through-hole IR receivers that work nicely with the high-brightness LED and 38 kHz modulation circuit of these proximity sensors: the TSSP58038 is a through-hole version of the surface-mount TSSP77038 detector on these proximity sensors, and the TSSP58P38 is a unique modulated IR receiver with an output that can be used to measure distance. You can use several of the proximity sensors with these discrete IR receivers to make sophisticated sensing solutions in which you enable one emitter at a time and monitor the reflections with the other sensors.