HY-SRF05 Ultrasonic distance sensor module 5 pins (OT3624)

The HY-SRF05 Ultrasonic Range Finder module uses ultrasonic sound waves to detect presence and measure the distance of objects in front of it.
KEY FEATURES:2cm - 450cm (15 feet) detection range40 kHz operation±15 degrees field of view5V operation
The detection and measurement range is from 2cm to 450cm with a stated accuracy of ± 2mm. The ultrasonic sound pulses at 40 kHz and is inaudible to the human ear. The HY-SRF05 is a higher precision version of the HC-SR04, but is otherwise similar in functionality.
These modules are often used on robotic vehicles for obstacle detection and avoidance. Because they use sound waves for detection, they are not sensitive to light sources or optically reflective surfaces as IR can be. Furthermore, by using sound instead of light it is possible to measure the time it takes for the sound to echo back and therefore the distance to the object can be calculated with a fair amount of accuracy which can be quite useful .
The modules have a 'sight' of around ±15 degrees, so they are sometimes mounted on a servo motor to allow the sensor to 'see' around its surroundings. The fact that the sensors act like a pair of eyes also adds to the cool factor.

HOW THE HY-SRF05 ULTRASONIC RANGE FINDER MODULE WORKS
The module is normally idle. A 10uSec or wider logic HIGH pulse is sent to the TRIG pin on the module, usually by a microcontroller. This will cause the module to enter a detection cycle.
The module will send out eight bursts of 40KHz sound and set its ECHO pin output HIGH. When the signal is reflected back from an object and detected by the module, the ECHO pin is set back to LOW.
By measuring how long the ECHO pin is held HIGH, the distance to the object can be calculated using the basic formula (Time ECHO is held HIGH * Speed of sound / 2) Divide by 2 because the sound has to travel in both directions (there and back) and we only want to know the distance.
If there is no echo return (no object detected or signal is blocked), the module will still lower the ECHO pin after a fixed delay. This delay can vary, but is around 200mSec on the modules I have measured. This is necessary to prevent the module from hanging when there is no echo.
The speed of sound varies slightly with air temperature, so for maximum accuracy the air temperature can be measured and used to calculate the current speed of sound, but it is not required for basic collision detection purposes.
Module Connections:There is a 5 pin header on the assembly. The GND pin is connected to system ground and the Vcc pin is connected to 5V. The TRIG pin is an input pin which is applied with a 10uSec pulse to start the measurement cycle. The ECHO pin is an output pin which is held HIGH for the time from when the module sends out a 40KHz pulse until it receives the echo back. The OUT pin is not used.
1 x 5 header
VCC – Connect to 5V. TRIG – Trigger Input – Connect to a digital output pin on the MCU. A pulse of 10 uSec or wider starts a measurement cycleECHO - Echo Output - Connect to a digital input pin on the MCU. This pin is held high during the measurement cycle.OUT - Not usedGND - Connect to system ground. This ground must be common with the MCU.