Description:

• Working Voltage : 5V(DC)
• Static Current: Less than 2mA.
• Output Signal: Electric frequency signal, high level 5V, low level 0V.
• Sensor Angle: Not more than 15 degrees.
• Detection Distance: 2cm-450cm.
• High Precision: Up to 0.3cm
• Input Trigger Signal: 10us TTL impulse
• Echo Signal : output TTL PWL signal
• Mode of connection:
• VCC
• trig(T)
• echο(R)
• GND

Use method:

Supply module with 5V, the output will be 5V while obstacle in range, or 0V if not.The out pin of this module is used as a switching output when anti-theft module, and without the feet when ranging modules.

Note : the module should be inserted in the circuit before been power, which avoid producing high level of misoperation;if not, then power again.

Module Working Principle:
1. Adopt IO trigger through supplying at least 10us sequence of high level signal.
2. The module automatically send eight 40khz square wave and automatically detect whether receive the returning pulse signal.
3. If there is signals returning, through outputting high level and the time of high level continuing is the time of that from the ultrasonic transmitting to receiving. Test distance =(high level time * sound velocity (340M/S) / 2.

Note :
This module is not suitable to connect with electric power, if you need to connect this module with electronic power,then let the GND terminal of this module to be connected first,otherwise, it will affect the normal work of the module

Ultrasonic Sensor Pinout Configuration

HC-SR04 Ultrasonic Sensor – Working

As shown above the HC-SR04 Ultrasonic (US) sensor is a 4 pin module, whose pin names are Vcc, Trigger, Echo and Ground respectively. This sensor is a very popular sensor used in many applications where measuring distance or sensing objects are required. The module has two eyes like projects in the front which forms the Ultrasonic transmitter and Receiver. The sensor works with the simple high school formula that

Distance = Speed × Time

The Ultrasonic transmitter transmits an ultrasonic wave, this wave travels in air and when it gets objected by any material it gets reflected back toward the sensor this reflected wave is observed by the Ultrasonic receiver module. Now, to calculate the distance using the above formulae, we should know the Speed and time. Since we are using the Ultrasonic wave we know the universal speed of US wave at room conditions which is 330m/s. The circuitry inbuilt on the module will calculate the time taken for the US wave to come back and turns on the echo pin high for that same particular amount of time, this way we can also know the time taken. Now simply calculate the distance using a microcontroller or microprocessor.

How to use the HC-SR04 Ultrasonic Sensor

HC-SR04 distance sensor is commonly used with both microcontroller and microprocessor platforms like Arduino, ARM, PIC, Raspberry Pie etc. The following guide is universally since it has to be followed irrespective of the type of computational device used.

  Power the Sensor using a regulated +5V through the Vcc ad Ground pins of the sensor. The current consumed by the sensor is less than 15mA and hence can be directly powered by the on board 5V pins (If available). The Trigger and the Echo pins are both I/O pins and hence they can be connected to I/O pins of the microcontroller. To start the measurement, the trigger pin has to be made high for 10uS and then turned off. This action will trigger an ultrasonic wave at frequency of 40Hz from the transmitter and the receiver will wait for the wave to return. Once the wave is returned after it getting reflected by any object the Echo pin goes high for a particular amount of time which will be equal to the time taken for the wave to return back to the sensor.

The amount of time during which the Echo pin stays high is measured by the MCU/MPU as it gives the information about the time taken for the wave to return back to the Sensor. Using this information the distance is measured as explained in the above heading.

 HC SR04 Ultrasonic Sensor Datasheet