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Use LinkIt 7697 to Make Fall Device


MediaTeklaunched LinkIt 7697 itis a powerful development board, but only used to do remote control car? Itrecklessly waste God's good gifts. The strengths of LinkIt 7697 is theperformance of processors and memory, it is faster and larger than most of 8bits ATMEL 328 series which used in the Arduino series. Of course, if addingthe complex calculus effect function , make it more interesting!

 

Atfirst, let's take a look at simple comparison tables for the LinkIt 7697 andArduino Uno:

comparisontable for LinkIt 7697 / Arduino Uno

 

Also, donot forget that LinkIt 7697 comes with BLE and WiFi radio, and if you want touse Arduino UNO to do radio value-added service, you have to pay extra moneyfor an Adapter!

 

If youwant to make it a strong effect of calculus,there is a lot of practicalapplications, the Arduino of this kind of device is suitable for LinkIt 7697.

 

After referringto several international journals, we can use LinkIt 7697 and MPU6050 module tomake a prototype for detecting fall signals.

 

How do I use LinkIt 7697 to make a fall detection device?

 

Materialrequirements

LinkIt7697 *1

MPU6050module *1

Femaleto female DuPont line *4

 

LinkIt7697 / Arduino Uno hardware jumper

 

Insimple terms, use the acceleration on the XYZ three axes, The intensity values(XYZ on the three axes of the value, this time with the previous difference,and then into the formula)of the XYZ variables obtained by time “t” ( set afixed interval) are analyzed and compared (compare to a set value).

 

If youare interested in international journals, you can find that some people aslsoconside the  angular speed (the extent of the changein the degree of self rotation) into account! (The same formula! Just ax, ay,az replaced gx, gy, gz only). In short, in a period of time, if the detectedstrength exceeds the set value, it is determined to fall.

 

Maybesomeone will be confused for those mathematical journals which dazzle the eyes.In fact, those international journals and seminars to write the theme of theliterature, that is: what kind of data collection methods (their own set oftheir own formula) to determine the intensity value should be set, it has beenconsidered a fall .

 

Code

<< fall.ino >>

#include “I2Cdev.h”

#include “MPU6050.h”

#include “Wire.h”

MPU6050 accelgyro;

int16_t ax, ay, az;

int16_t gx, gy, gz;

int time_interval = 500;   //500ms

unsigned long current, lastTime = 0;

int16_t prev_accx = 0;

int16_t prev_accy = 0;

int16_t prev_accz = 0;

float acc_upv = 2.8;  //Thethresholds for fall detection

void setup()

{

  Wire.begin();

  Serial.begin(115200);

  accelgyro.initialize();

  accelgyro.getMotion6(&ax,&ay, &az, &gx, &gy, &gz);

  prev_accx = ax;

  prev_accy = ay;

  prev_accz = az;

  lastTime = millis();

}

void loop()

{

  current = millis();                //Set for every interval

  if(current – lastTime >=time_interval)

  {

    lastTime = current;

   accelgyro.getMotion6(&ax, &ay, &az, &gx, &gy,&gz);

    

    float accx = ((ax –prev_accx) / 16384) * ((ax – prev_accx) / 16384);

    float accy = ((ay –prev_accy) / 16384) * ((ay – prev_accy) / 16384);

    float accz = ((az –prev_accz) / 16384) * ((az – prev_accz) / 16384);

    Serial.print(accx);Serial.print(“\t”);

    Serial.print(accy);Serial.print(“\t”);

    Serial.print(accz);Serial.println();

    if( sqrt(accx + accy +accz) > acc_upv )

     Serial.println(“GOT!!!”);

    prev_accx = ax;

    prev_accy = ay;

    prev_accz = az;

  }

}

Author:Lai Jian红


Articlesource:https://makerpro.cc/2017/07/design-falling-sensing-device-by-linkit-7697/



1092663243Aug 13,2017 23:54 PMAdd Comment

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