RF transmission of data seems blocked

Thread Starter

quique123

Joined May 15, 2015
346
I have this 4wd car platform and Im using these as the Rx and Tx sketches. The car uses an Arduino UNO with an L293D driver shield with a RF433Mhz Rx module. The UNO is powered from a 9V barrel jack and the Motors are powered from 4xAA battery pack. The Rx is a nano with a 433Mhz Rx and an MPU6050 module, powered from a mobile phone battery pack.

The problem
If I tilt the MPU6050 left or right, the car correctly turns either 1 wheel or the other, to make it turn. As soon as I return to the "flat" position it stops turning. But when I tilt the MPU6050 to the back or front, it correctly runs forward or backward but it never stops after that.

Here is the Rx:

Code:
// Include RadioHead Amplitude Shift Keying Library
#include <RH_ASK.h>
// Include dependant SPI Library 
#include <SPI.h> 
#include <AFMotor.h>

// Create Amplitude Shift Keying Object
RH_ASK rf_driver;

//Define packet for the direction (X axis and Y axis)
int data[2];

AF_DCMotor motor1(1, MOTOR12_64KHZ); // create motor #1, 64KHz pwm
AF_DCMotor motor2(2, MOTOR12_64KHZ); // create motor #2, 64KHz pwm
AF_DCMotor motor3(3, MOTOR12_64KHZ); // create motor #3, 64KHz pwm
AF_DCMotor motor4(4, MOTOR12_64KHZ); // create motor #4, 64KHz pwm

String str_out;

void setup() {
  Serial.begin(9600);
  rf_driver.init();

  motor1.setSpeed(200);     // set the speed to 200/255
  motor2.setSpeed(200);     // set the speed to 200/255
  motor3.setSpeed(200);     // set the speed to 200/255
  motor4.setSpeed(200);     // set the speed to 200/255

}

void loop() {
// Set buffer to size of expected message
    int receivedData[3] = {0};
    uint8_t buflen = sizeof(receivedData);
    if (rf_driver.recv((uint8_t*)receivedData, &buflen)) {
      //if data is not an array, use &receivedData
    for (byte i = 0; i < 3; i++) {

    }
    if(receivedData[0] > 380){
      left();
      Serial.println("LEFT"); //motor back left
    }
    if(receivedData[0] < 310){
      right();
      Serial.println("RIGHT"); //motor back right
    }
    if(receivedData[1] > 180){
      forward();
      Serial.println("FORWARD"); //motor bl and br direction 1
    }
    if(receivedData[1] < 110){
      backward();
      Serial.println("BACKWARD"); //motor bl and br direction 2
    }
    if(receivedData[0] > 330 && receivedData[0] < 360 && receivedData[1] > 130 && receivedData[1] < 160){
      //brake();
      stopCar();
      Serial.println("STOP");
    }
  }

}

void forward(){
  Serial.println("running forward");
  motor1.run(FORWARD);  
  motor2.run(FORWARD);
  motor3.run(FORWARD);  
  motor4.run(FORWARD);    

}
void backward(){
  Serial.println("running backward");
  motor1.run(BACKWARD);  
  motor2.run(BACKWARD);
  motor3.run(BACKWARD);    
  motor4.run(BACKWARD);    
}

void left(){
  motor3.run(FORWARD);  
}
void right(){
  motor4.run(FORWARD);    
}

void brake(){
  motor1.run(RELEASE);    
  motor2.run(RELEASE);    
  motor3.run(RELEASE);    
  motor4.run(RELEASE);      
}

void stopCar(){
  motor1.run(RELEASE);    
  motor2.run(RELEASE);    
  motor3.run(RELEASE);    
  motor4.run(RELEASE);    
}
And the Tx code:

Code:
// Include RadioHead Amplitude Shift Keying Library
#include <RH_ASK.h>
// Include dependant SPI Library 
#include <SPI.h> 
#include "Wire.h"       //For communicate
#include "I2Cdev.h"     //For communicate with MPU6050
#include "MPU6050.h"    //The main library of the MPU6050

//Define the object to access and cotrol the Gyro and Accelerometer (We don't use the Gyro data)
MPU6050 mpu;
int16_t ax, ay, az;
int16_t gx, gy, gz;

//Define packet for the direction (X axis and Y axis)
int data[2];

// Create Amplitude Shift Keying Object
RH_ASK rf_driver;

void setup() {
  Serial.begin(9600);
  mpu.initialize();              //Initialize the MPU object

  // Initialize ASK Object
  rf_driver.init();

}

void loop() {
  delay(2000);

  //With this function, the acceleration and gyro values of the axes are taken. 
  //If you want to control the car axis differently, you can change the axis name in the map command.
  mpu.getMotion6(&ax, &ay, &az, &gx, &gy, &gz);
    //In two-way control, the X axis (data [0]) of the MPU6050 allows the robot to move forward and backward. 
  //Y axis (data [0]) allows the robot to right and left turn.
  data[0] = map(ax, -17000, 17000, 300, 400 ); //Send aX axis data
  data[1] = map(ay, -17000, 17000, 100, 200);  //Send aY axis data
   
  rf_driver.send((const uint8_t*)data, sizeof(data));
  //(uint8_t *)msg, strlen(msg));
  rf_driver.waitPacketSent();
  Serial.println(data[0]);
  Serial.println(data[1]);
   
}
If you think it necessary to post pictures of the car and wiring I will, but I dont think it would be very clear. Id upload a sketch but I dont think the wiring is the issue because it seems to me its a coding issue rather than a wiring issue.
 
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