Humidity Datalogger

Projects Programming
1

Hello
I'm new with arduino and i'm writing a code using datalogger and DHT_11 humidity and temperature sensor. I want to save every 30 second datas for 10 minutes in the sd card... also i want arduino to send the last 10 minute datas by bluetooth. The first part is ikay. But i have problems weiting the second part. Can you help me?

2

We can't see your code.
We can't see your schematic.

3

sorry, here is my code: this was for photocell data logging for 30 sec intervals, now i want to write a code which commands from the cellphone and sends back the last 10 minute data. at first i thought if i make an array of 20 buckets, and put it in a loop, then send the loop function to android would make it right, but it just sends me continues data. i only want the last 10 minute data of the program.

float sensorvalue[20];

void setup() {
// put your setup code here, to run once:
Serial.begin(9600);
for (int i = 0; i < 20; i++) {
pinMode(sensorvalue*, OUTPUT);*

  • }*
    }
    void loop() {
  • // put your main code here, to run repeatedly:*
    sendvalues();
    char c;

if(Serial.available())
{

  • c=Serial.read();*
  • if (c=='t')*
    sendvalues();
    }
    }
  • void sendvalues(){*
  • for (int i=0 ; i<20 ; i++){*
    _ Serial.println(sensorvalue*);_
    _ sensorvalue = analogRead(A0);
     delay(30000); //every 30 seconds read data*
    * if (i>=20) {
     i=0; //reset to beginning of array, so you don't try to save readings outside of the bounds of the array*
    * } }
    Serial.println("***********************************");
     }*_
4

Messing about with for loop control variables inside the for loop rarely goes well, unless you really know what you're doing.

Please use code tags when posting code.

5

So any suggestions?

6

So, any code tags?

7 
float sensorvalue[20];

void setup() {
  // put your setup code here, to run once:
Serial.begin(9600);
  for (int i = 0; i < 20; i++) {
    pinMode(sensorvalue, OUTPUT);
  }
}

void loop() {
  // put your main code here, to run repeatedly:
sendvalues();
char c;

 if(Serial.available())
 {
  c=Serial.read();
  if (c=='t')
sendvalues();
}
}
  void sendvalues(){
    for (int i=0 ; i<20 ; i++){
    Serial.println(sensorvalue);
    sensorvalue   = analogRead(A0);
    delay(30000); //every 30 seconds read data

    if (i>=20) {
    i=0; //reset to beginning of array, so you don't try to save readings outside of the bounds of the array
  }  }
 Serial.println("***********************************");
  }
8

Tell us what you think is going on in the for loop in setup.

9

Elements in an array is accessed with an index, like this:

const byte ARRAY_LEN = 10;
float floatArray[ARRAY_LEN];
floatArray[index] = someValue; //index must be in range 0..ARRAYLEN-1

Therefore this is an ooops..

for (int i = 0; i < 20; i++) {
    pinMode(sensorvalue, OUTPUT);
  }

This is another ooops..

Serial.println(sensorvalue);
sensorvalue   = analogRead(A0);

This is useless in a for loop:

if (i>=20) {
    i=0; //reset to beginning of array, so you don't try to save readings outside of the bounds of the array
  }
10

Therefore this is an ooops..

No, it is, at the very least, a double oops.