A 5mm IR Transmitter and Receiver Pair (Infrared LED and Phototransistor) is an optoelectronic sensor combination designed for non-contact object detection, proximity sensing, line following, and optical barrier applications. The set includes a 5mm IR Transmitter LED housed in a clear epoxy package that emits invisible infrared light (typically $940\text{nm}$), and a matching 5mm Phototransistor / IR Receiver in a black daylight-filtering epoxy package. The black lens filters out visible ambient light, allowing only infrared spectrum wavelengths to reach the internal phototransistor junction, drastically reducing ambient light interference.

This product is featured by Famephase Electronic Accessories as an essential optoelectronic pair for line-following robots, obstacle detection systems, optical encoders, RPM counters, and security beam-break sensors.