HY-SRF05 Precision Ultrasonic Sensor An ultrasonic ranging sensor with slightly better accuracy. Ultrasonic sensors overcome many of the weaknesses of IR sensors - they provide distance measurement regardless of color and lighting of obstacles. They also provide lower minimum distances and wider angles of detection to gaurantee that obstacles are not missed by a narrow sensor beam. THIS particular model is an upgrade from the lower precision HC-SRO4. This has 5 pins and can be used in 1pin trigger/echo or 2-pin. The SRF05 UltraSonic range finder lets you find the distance of the objects in front of it. It does that by sending ultrasonic pulses and measures the time it takes for the pulses to travel to the obstacle and back. Ultrasonic ranging module HY-SRF05 provides 2cm - 400cm non-contact measurement function, the ranging accuracy can reach to 3mm. The module includes transmitters, receiver and control circuit. The SRF05 is an evolutionary step from the SRF04, and has been designed to increase flexibility, increase range, and to reduce costs still further. As such, the SRF05 is fully compatible with the SRF04. Range is increased from 3 meters to 4 meters. A new operating mode (tying the mode pin to ground) allows the SRF05 to use a single pin for both trigger and echo, thereby saving valuable pins on your controller. When the mode pin is left unconnected, the SRF05 operates with separate trigger and echo pins, like the SRF04. The SRF05 includes a small delay before the echo pulse to give slower controllers such as the Basic Stamp and Picaxe time to execute their pulse in commands. the module performance is stable, measure the distance accurately: Can and SRF05, SRF02 ultrasonic distance measuring module and other comparable. Module precision, blind spots (2cm) super close, stable ranging success of this product to market under the strong! Pins Details 5-Pin, One each for VCC, Trigger, Echo, Out and Ground. Trig : Plusing a HIGH on this pin will send a Pulse Echo