Hi All,
I am working on a school project that involves data collection. We take 12,000 samples per minute and export this data to a csv file stored on an SD card datalogger shield attached to our arduino. This part works perfectly, however, after collecting this data, we need to send it over wifi to something (it doesn't matter what, could be a server, webpage, etc). Currently to do this, we have a working arduino/ESP8266 setup that can read the SD card file line by line and send it to thingspeak. However, Thingspeak is very slow (1 datapoint every 15 seconds) and with our data rate, it will take 20 days to send a single minute of our data.
We have tried:
-Sending bulk data using json (only could get up to 7 samples at a time)
-Sending a string with multiple entries in it and parsing it after sending it (ran into issues with the Arduino's memory limitations, could only make the string so long)
Does anyone have any suggestions on how to increase the speed of the data sending? Is it even possible?
The code we are currently using for the wifi sending part of our project (15 seconds/data point) is below:
EDIT: Posted the wrong code the code we are actually using is below:
#include <SD.h>
#include <SoftwareSerial.h>
#define errorHalt(msg) {Serial.println(F(msg)); while(1);}
#define RX 2
#define TX 3
String AP = "[removed for privacy]"; // CHANGE ME
String PASS = ""; // CHANGE ME
String API = "[removed for privacy]"; // CHANGE ME
String HOST = "api.thingspeak.com";
String PORT = "80";
String field = "field1";
int countTrueCommand;
int countTimeCommand;
boolean found = false;
String valSensor = "";
const int cs = 10;
SoftwareSerial esp8266(RX, TX);
void setup() {
Serial.begin(9600);
esp8266.begin(9600);
sendCommand("AT",5,"OK");
sendCommand("AT+CWMODE=1",5,"OK");
sendCommand("AT+CWJAP=""+ AP +"",""+ PASS +""",20,"OK");
pinMode(10, OUTPUT);
// see if the card is present
if (!SD.begin(cs))
{
Serial.println("Card failed to initialize, or not present");
return;
}
Serial.println("card initialized.");
File myfile = SD.open("ADC~4BE3.CSV");
Serial.println("open");
// if the file is available, read the file
if (myfile)
{
myfile.seek(0);
size_t n; // Length of returned field with delimiter.
char str[20]; // Must hold longest field with delimiter and zero byte.
int count=0;
while (myfile.available())
{
// Read the file and print fields.
while (true) {
n = readField(&myfile, str, sizeof(str), ",\n");
// done if Error or at EOF.
if (n == 0) break;
// Print the type of delimiter.
if (str[n-1] == ',' || str[n-1] == '\n') {
// Serial.print(str[n-1] == ',' ? F("comma: ") : F("endl: "));
// Remove the delimiter.
str[n-1] = 0;
count++;
} else {
// At eof, too long, or read error. Too long is error.
Serial.print(myfile.available() ? F("error: ") : F("eof: "));
}
// Print the field.
if ((count%2)==0){
Serial.println(str);
valSensor = str;
String getData = "GET /update?api_key="+ API +"&"+ field +"="+String(str);
sendCommand("AT+CIPMUX=1",5,"OK");
sendCommand("AT+CIPSTART=0,"TCP",""+ HOST +"","+ PORT,15,"OK");
sendCommand("AT+CIPSEND=0," +String(getData.length()+4),4,">");
esp8266.println(getData);delay(15000);countTrueCommand++;
sendCommand("AT+CIPCLOSE=0",5,"OK");
}
}
}
myfile.close();
Serial.write("Closed");
}
}
void loop() {
}
int getSensorData(){
return random(1000); // Replace with the SD card file
}
void sendCommand(String command, int maxTime, char readReplay[]) {
Serial.print(countTrueCommand);
Serial.print(". at command => ");
Serial.print(command);
Serial.print(" ");
while(countTimeCommand < (maxTime*1))
{
esp8266.println(command);//at+cipsend
if(esp8266.find(readReplay))//ok
{
found = true;
break;
}
countTimeCommand++;
}
if(found == true)
{
Serial.println("OYI");
countTrueCommand++;
countTimeCommand = 0;
}
if(found == false)
{
Serial.println("Fail");
countTrueCommand = 0;
countTimeCommand = 0;
}
found = false;
}
size_t readField(File* file, char* str, size_t size, char* delim) {
char ch;
size_t n = 0;
while ((n + 1) < size && file->read(&ch, 1) == 1) {
// Delete CR.
if (ch == '\r') {
continue;
}
str[n++] = ch;
if (strchr(delim, ch)) {
break;
}
}
str[n] = '\0';
return n;
}