IOE-SR05 โมดูลเซ็นเซอร์วัดระยะทาง Ultrasonic IOE-SR05 Range ultrasonic module ttl serial port output

IOE-SR05 ULTRASONIC RANGING MODULE FEATURES:

• small size, PCB board size is only 2.2 * 3 .6CM, suitable for use with high size requirements;
• at least one IO data port can accept the hexadecimal data of the measured distance; with the data output enable terminal, it can be controlled by the IO port or directly grounded!
• the measurement distance period is only 18ms, which greatly reduces the measurement time, especially for the use of robot control;
• reached the theoretical no blind zone, basically no blind zone test range;
• OVERRANGE AUTOMATICALLY RETURN AAAA DATA, REDUCE THE WAITING TIME AFTER OVERRANGE;
• there is a red LED on the back to indicate the working status, when there is an obstacle, the LED will light up

ultrasonic ranging module wiring mode:

• five 2.54mm pitch pins:
• VCC - wide voltage input: support 3v-5.5v
• TxD——(Serial output, RXD for microcontroller or TTL board;)
• Enable-(Enable end, module works when =0, does not work when =1, PCB printing Trig),
• GND – POWER SUPPLY GROUND
• GND – POWER SUPPLY GROUND

Data format:

THE MODULE OUTPUTS 4 BYTES AT A TIME IN THE FORMAT OF: 0XFF + H_DATA + L_DATA + SUM

• 0XFF: Is a set of starting data that is used for judgment.
• H_DATA: 8 bits higher than the distance data.
• L_DATA: 8 bits lower than the distance data.
• SUM: Data and, for validation. Its 0XFF + H_DATA + L_DATA = SUM (only 8 bits lower).

NOTE: H_DATA SYNTHESIZES 16 BITS OF DATA WITH L_DATA, I.E. DISTANCE VALUES IN MILLIMETERS.

H_DATA * 256 +L_DATA
OVERRANGE FIXED OUTPUT: FF AA AA 53

THERE IS A RED LED ON THE BACK TO INDICATE THE WORKING STATUS, AND WHEN THERE IS AN OBSTACLE, THE LED WILL LIGHT UP.

Electrical parameters:

How to use this product: after confirming the polarity of the power supply and the voltage is connected, the module will automatically measure in 18ms cycle, if the echo is received, it will output the protocol data containing distance information (in mm) through the TXD output, and the output is very stable after actual testing.

how the module works:

• the module automatically sends 8 40khz square waves with a period of 18ms to automatically detect whether there is a signal return;
• THERE IS A SIGNAL RETURN, AFTER INTERNAL CALCULATION AND PROCESSING, THE DISTANCE INFORMATION IS OUTPUT THROUGH TXD;

• ultra-miniature, only equivalent to two transmitters, the area of the receiving head, can no longer be small.
• there is no blind spot (the error of forming triangles within 12mm is large).
• the reaction speed is fast, the measurement period of 18ms, it is not easy to lose the high-speed target.
• the transmitter head, the receiving head is close to each other, and the measured target is basically in a straight line relationship (within 12mm or a large triangle, this is the transmitter, the physical shape of the receiving head is determined).
• THERE ARE LED INDICATIONS ON THE MODULE, WHICH IS CONVENIENT FOR OBSERVATION AND TESTING!

frequently asked questions (faq):

 1: ultrasonic ranging principle

Ultrasonic is a sound with a relatively high frequency and strong directivity. The principle of ultrasonic ranging is to use the ultrasonic propagation speed in the air to be known, measure the time when the sound wave encounters an obstacle after transmission and reflect back, and calculate the actual distance from the transmission point to the obstacle according to the time difference between the transmission and reception. It can be seen that the principle of ultrasonic ranging is the same as the principle of radar.
The formula for ranging is expressed as: L = C× T
formula in which L is the measured distance length; C is the propagation speed of ultrasonic waves in the air; T is the time difference between the measured distance propagation (T is half of the value of the transmitted time to receive).
Known ultrasonic speed C=344m/s (20°C room temperature)

Ultrasonic propagation speed error
The propagation speed of ultrasonic waves is affected by the density of air, the higher the density of air, the faster the propagation speed of ultrasonic waves, and the density of air has a close relationship with temperature, the approximate formula is: C = C0 + 0.607 × T ° C
formula: C0 is zero when the sound wave speed is 332m / s;
T is the actual temperature (°C).
40khz ultrasonic wavelength is about 8mm, and the detection is the peak level, so it is easy to error a wavelength of 8mm, so it is not possible to achieve very high precision, and do not have to care about the influence of temperature (temperature influence is second)

2: why is the farthest distance only 2000mm?

this sensor is designed for smart cars and other micro equipment, suitable for small range, small space, closed space occasions, we all know, ultrasonic transmission speed is low, long attenuation time, if blindly pursue distance, it will lead to long response time, loss of target, in the indoor and other closed occasions will form multiple emission shocks, the sensor can not work properly.

the following analyzes the distance problem from the sensor's reaction time:

ultrasonic air speed of about 340 meters per second, converted into milliseconds, is 340mm / ms, detection distance of 2000mm, the distance detected to the echo is 4000mm, ultrasonic transmission time is 12ms, plus circuit delay, sensor energy delay, and then reserve some protection time (let the last ultrasonic energy disappear), each measurement time is 18ms.18ms the reaction speed is suitable for smart cars, and the target will not be lost when moving at high speed.

Now there is a sensor on the market is 5 meters, this 5 meters is the maximum distance, the detection target is generally a large emission surface such as the wall, for small targets is impossible to achieve, first regardless of how far this small target is, we analyze from the sensor's reaction time. The timing of this sensor is different from ours in that it receives feedback first and then feeds back from echo's pulse width, rather than from the jet lag between echo and trig, doubling the sensor's response time! The minimum response time of this 5-meter sensor is (the minimum time of 1 meter calculated above is 6ms): 5 *6*2=60ms! Even if the fastest measurement cycle of 60ms is too slow for smart cars! When the master CPU detects the target, the car may have crashed!

3: your ultrasonic transmitter and receiver head are very close, why?

the ultrasonic sensor we see is generally separated from the transmitter and the receiving head, because the closer to the transmitter head, the higher the transverse wave energy is transmitted to the receiving head, resulting in a large blind spot, or even unable to work properly, so that the transmitter and the receiving head are separated from the point is not allowed, so the disadvantage of the belt is the transmitter, and the triangle connection between the receiving head and the measuring object is! obviously, the closer the distance, the greater the angle of the triangle, which brings error. the transmitter and receiver heads of the sensors are closely adjacent, and the detection target is a parallel relationship, not a triangular relationship.

4: does your ultrasonic module really have no blind spots?

the originality of this ultrasonic sensor eliminates lateral interference waves and the minimum measurement distance starts from 0.

5: different objects measure different distances?

right! because ultrasonic waves are sounds with higher frequencies, different materials and shapes of objects have different absorption rates of sound, different reflection angles, and only the energy reflected to the receiving head (that is, the direction of ultrasonic emission) will be detected, so the effective measurement distance of different objects is different. in general, the flat smooth object (such as the mirror surface) reflection distance is the farthest, usually said that the maximum detection distance refers to this type of object, the detection distance of small objects is very close, such as fine cotton line, the area is small, and absorb the sound, it can not be detected.

the maximum detection distance for an actual object is listed below:

• ballpoint pen, 200mm
• hand, 400mm
• 1mm thick wire with plastic sleeve, 30mm
• vernier caliper, 450mm
• human body (wear thick clothes), 400mm
• wall, 2.200mm (maximum about 2300mm, vertical measurement required)
• 1mm thick cotton thread, undetectable
• bamboo toothpick, 40mm