So far, we have seen the TSOP and SM devices as examples of transmitters. We also saw IR LEDs as transmitters. There is one more category of components known as transceivers. As the name suggests, transceivers are a combination of a transmitter and a receiver built-in together as a single electronic component or module.
We have already seen an example of a transceiver in Chapter 6, Day 4 - Building a Standalone Device. The HC-SR04 Ultrasonic sensor is actually a transceiver. It transmits ultrasonic waves and also receives the reflected ultrasonic waves.
Similarly, just like the HC-SR04 Ultrasonic sensor we can pair an IR Transmitter LED with a photodiode to build a transceiver component to measure distances. This type of Infrared transceiver is used as a proximity sensor of various robotic vehicles to sense obstacles and navigate itself.