Edwar Baihaqi

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10 years, 10 months ago.  This question has been closed. Reason: has been answered

LM35+Xbee PRO+MBED = subscript out of range

hi guys, i am working with temprature sensor(LM35), an xbee pro, and an mbed right now. i want to make a very simple prototype of nanosatellite. the system will measure the prototype temprature and transmit the temprature data using Xbee Pro. as the ground segment, i just using Xbee PRO+Xbee adapter+XTCU software. i tried to make the program based on the cookbook, modified it, and here it is, the program. but the problem is, when i compiled it, there are two warning statement.

  1. subscript out of range
  2. write to variable 'tempC' with offset out of bounds

main.cpp

#include "mbed.h"
#include "xbee.h"

//Print temperature from LM35 analog temperature sensor

//set p19 to analog input to read LM35 sensor's voltage output
AnalogIn LM35(p19);
xbee xbee1(p9,p10,p11); //Initalise xbee_lib
Serial pc(USBTX, USBRX); //Initalise PC serial comms

//also setting unused analog input pins to digital outputs reduces A/D noise a bit
//see http://mbed.org/users/chris/notebook/Getting-best-ADC-performance/
/*DigitalOut P16(p16);
DigitalOut P17(p17);
DigitalOut P18(p18);
DigitalOut P19(p19);
DigitalOut P20(p20);*/

int main()
{
    float tempC[202];
    char b[202];
        
    while(1) {
        //conversion to degrees C - from sensor output voltage per LM61 data sheet
        tempC[202] = ((LM35*3.3)-0.6)*100.0;
        printf("%5.2f C \n",tempC[202]);
        memcpy(b, &tempC, 202);
        wait(1);
        xbee1.SendData(b);
        }
}

i have no idea to resolve these problems. is there any idea to resolve these problems?

2 Answers

Erik -
10 years, 10 months ago.

It is handy to mention where the error is found, then we know where to look.

Anyway you have two buffers of 202 bytes. You use only tempC[202], but if a buffer is 202 bytes long it is defined from zero to 201 bytes, 202 is outside its scope.

Problem two is you copy tempC into b. However tempC is a float, and a float is 4 bytes long, while b is a char, and a char is a single byte. So that doesn't fit.

Accepted Answer
Edwar Baihaqi
poster
10 years, 10 months ago.

thank you very much, it works well!!!