Inaccurate result when combining LM35 + XBee

[cutie_lovely_92]

I am currently doing a project reading Body temperature and pulse sensor that will sent the result wirelessly through XBee.
I started by trying each components separately and everything works fine.

Problem:
Inaccurate result when I combine the XBee and LM35 sensor.
The sensor keep giving the same result. Here's the sketch output.

Code: Select all

LM35 Thermometer 
Analog in reading: 1023 - Calculated Temp: 109.8
Analog in reading: 1023 - Calculated Temp: 109.8
Analog in reading: 1023 - Calculated Temp: 109.8
Analog in reading: 1023 - Calculated Temp: 109.8

I am very sure that before combining it with XBee everything works just fine.
Can anyone explain to me what's the problem here?
Do it need any voltage adjustment or something?

[adafruit_support_bill]

Post a photo showing all your connections. And post the code you are using too.

[cutie_lovely_92]

Post a photo showing all your connections. And post the code you are using too.

Code: Select all

#include <SoftwareSerial.h>

SoftwareSerial xbee(2, 3); //RX, TX

int potPin = 0;
float temperature = 0;
void setup()
{
  Serial.begin(9600);
  Serial.println("LM35 Thermometer ");
  analogReference(INTERNAL);
  xbee.begin(9600);
}
void printTenths(int value) {
  // prints a value of 123 as 12.3
  Serial.print(value / 10);
  xbee.print(value/10);
  Serial.print(".");
  xbee.print(".");
  Serial.println(value % 10);
  xbee.print(value % 10);
}
void loop() {
  int span = 20;
  int aRead = 0;
  for (int i = 0; i < span; i++) {
    aRead = aRead+analogRead(potPin);
  }
    aRead = aRead / 20;
    temperature = ((100*1.1*aRead)/1024)*10;
    // convert voltage to temperature
    Serial.print("Analog in reading: ");
    Serial.print(long(aRead));
    // print temperature value on serial monitor
    Serial.print(" - Calculated Temp: ");
    xbee.print(" - Calculated Temp: ");
    printTenths(long(temperature));
    
    delay(500);
}

[adafruit_support_bill]

Appears to be wired right. But your raw reading is at max scale. You should contact the seller of the LM35.

[Yeoh]

I face same problem when combining my LM35 +Xbee series 1 pro.
i connected Vref to Vcc on xbee explorer. as i read the data sheet the adc input voltage is 3.3v. My program on calculation suppose to *3.3v but I still unable to achieve proper reading.



#include <SoftwareSerial.h>]

SoftwareSerial xbee(0, 1); //RX, TX

int potPin = 0;
float temperature = 0;
void setup()
{
Serial.begin(9600);
Serial.println("LM35 Thermometer ");
analogReference(INTERNAL);
xbee.begin(9600);
}
void printTenths(int value) {
// prints a value of 123 as 12.3
Serial.print(value / 10);
xbee.print(value/10);
Serial.print(".");
xbee.print(".");
Serial.println(value % 10);
xbee.print(value % 10);
}
void loop() {
int span = 20;
int aRead = 0;
for (int i = 0; i < span; i++) {
aRead = aRead+analogRead(potPin);
}
aRead = aRead / 20;
temperature = ((100*3.3*aRead)/1024)*10;
// convert voltage to temperature
Serial.print("Analog in reading: ");
Serial.print(long(aRead));
// print temperature value on serial monitor
Serial.print(" - Calculated Temp: ");
xbee.print(" - Calculated Temp: ");
printTenths(long(temperature));

delay(500);
}