The transmitter and receiver are in the same housing in this type of ultrasonic sensor. A single ultrasonic transducer is switched cyclically between transmit and receive mode. The object itself acts as the sound reflector.

Product features:

• The sensing range depends on the reflectivity of the object, including the surface properties and the angle of incidence. These effects can be compensated for (within limits) by a sensitivity adjustment
• Low installation expense, since the sensor consists of just one unit
• Sensitive to changes in the reflective properties of the target

Placing separate transducers for transmitting and receiving next to each other in the same housing significantly reduces the blind range since there is no need to wait for the transmitter signal to decay.

Ultrasonic sensors with discrete outputs and analog outputs are available as direct detection sensors. All direct detection sensors that support the "Window mode" output function can also be used as retro-reflective sensors (see retro-reflective sensors).