Trying to loop a http request using the Arduino Adafruit CC3000 Webclient - arduino

I am trying to retrieve data from a webpage to my Arduino on a looping 5 second interval. I'm building off the Adafruit CC3000 'Webclient' example.
The complete code can be seen here.
Everything works as expected, the Arduino connects to the network and then makes a single request to the specified website.
Now I'm trying to add the loop, so that the Arduino gets the refreshed data. I don't want to disconnect and then have to reconnect to the wifi network so I tried to loop the following code.
void myLoop(uint32_t ip)
{
// START LOOPING
int count = 0;
while(count == 0) {
Adafruit_CC3000_Client www = cc3000.connectTCP(ip, 80);
if (www.connected()) {
www.fastrprint(F("GET "));
www.fastrprint(WEBPAGE);
www.fastrprint(F(" HTTP/1.1\r\n"));
www.fastrprint(F("Host: ")); www.fastrprint(WEBSITE); www.fastrprint(F("\r\n"));
www.fastrprint(F("\r\n"));
www.println();
} else {
Serial.println(F("Connection failed"));
return;
}
/* Read data until either the connection is closed, or the idle timeout is reached. */
//unsigned long lastRead = millis();
while (www.connected()) {
while (www.available()) {
char c = www.read();
content = c;
Serial.print(c);
//lastRead = millis();
}
}
www.close();
Serial.println(F("\n\nDisconnecting"));
cc3000.disconnect();
delay(5000);
}
}
The loop runs perfectly once, but after the first iteration continually outputs "Connection Failed".
It appears that I cannot run the connectTCP function more than once but I cannot understand why
Adafruit_CC3000_Client www = cc3000.connectTCP(ip, 80);
I've also tried removing this from the loop and removing the www.close(); and cc3000.disconnect(); but it still fails to leave the connection open.
Any assistance would be greatly appreciated.

I'm also new using CC3000 and had a same problem with that code before.
you cannot connecting again because you put cc3000.disconnect(); inside the loop()
so just remove it, but keep the www.close(); in the loop().

I had the same issue, the cc3000 connecting only once or 3-4 http requests (Get) before crashing.
Now i have it working like this:
on the loop():
Adafruit_CC3000_Client www = cc3000.connectTCP(ip, WEBPORT);
delay(300);
if (www.connected()) {
//your http request get
//with a connection close:
www.fastrprint(F("GET "));
//inser your stuff
www.fastrprint(F("Connection: close\r\n"));
www.fastrprint(F("\r\n"));
www.println();
} else {
Serial.println(F("Connection failed"));
return;
}
//reading response
while(www.connected()){
while (www.available()) {
char c = www.read();
Serial.print(c);
}
}
www.stop();
delay(100);
www.close();
delay(200);
and stop&close the client at the end.
Hope this helps someone.. took mi so long to have this easy stuff working!

Related

esp32 BLE client application - connect to device name

I've hacked apart the ESP32 BLE arduino sketches to do what I want. The server side is easy. Please see code below:
if (con == 0){
digitalWrite(LED, LOW);
}
if (con == 1){
digitalWrite(LED, HIGH);
delay(1000);
digitalWrite(LED, LOW);
delay(1000);
}
if (deviceConnected) {
pCharacteristic->setValue((uint8_t*)&value, 4);
pCharacteristic->notify();
value++;
delay(3); // bluetooth stack will go into congestion, if too many packets are sent, in 6 hours test i was able to go as low as 3ms
con = 1;
}
// disconnecting
if (!deviceConnected && oldDeviceConnected) {
delay(500); // give the bluetooth stack the chance to get things ready
pServer->startAdvertising(); // restart advertising
Serial.println("start advertising");
oldDeviceConnected = deviceConnected;
con = 0;
}
This works exactly how I want. It simply sits idle doing nothing, when a device connects to the BLE server then it will flash an LED.
No problems there, even though I suspect my code isn't 'that pretty.
What i'm having trouble doing however is creating an ESP32 client to connect to the BLE device.
The client has the name set as
BLEDevice::init("BOX_A1");
The example code seems to want UID for both the service and characteristic. Is there any way to just connect to the short advertised name? No data is being shared, it's just simply acting as a beacon to identify a box when connected to.
Thanks
Andrew
You can't connect to a device using the advertised name, not directly at least.
If you want to use the advertised name you have to scan for all BLE devices around you and select the one matching your name. The BLE scan example shows you how this is done. The code scans for a scanTime of 5 seconds, waits 2 seconds and starts scanning again:
void loop() {
// put your main code here, to run repeatedly:
BLEScanResults foundDevices = pBLEScan->start(scanTime, false);
Serial.print("Devices found: ");
Serial.println(foundDevices.getCount());
Serial.println("Scan done!");
pBLEScan->clearResults(); // delete results fromBLEScan buffer to release memory
delay(2000);
}
The example just prints the amount of found devices, you want to search through them and look for the correct name. The BLEScan returns an object of type BLEScanResults. You can access the found devices using getDevice with an index. Something like this might work to print the names of all found devices:
BLEAdvertisedDevice device;
for (int i = 0; i < foundDevices.getCount(); ++i) {
device = foundDevices.getDevice(i);
Serial.println(device.getName().c_str());
}
Now you can compare the names and work with the correct device.
To my understanding,
You want the client to connect to the server with given advertised name.
After connection is success, server turns on led.
You do have notification service running on server, but your client isn't interested.
Below is the client code which only connects to server with name "BOX_A1".
First Set our callback function that checks if device name matches when scanner discovers the devices:
class MyAdvertisedDeviceCallbacks: public BLEAdvertisedDeviceCallbacks
{
void onResult(BLEAdvertisedDevice advertisedDevice)
{
if (advertisedDevice.getName() == "BOX_A1")
{
advertisedDevice.getScan()->stop(); //Scan can be stopped, we found what we are looking for
foundDevice = new BLEAdvertisedDevice(advertisedDevice);
deviceFound = true;
Serial.print("Device found: ");
Serial.println(advertisedDevice.toString().c_str());
}
}
};
Use the BLEAdvertisedDevice object i.e. foundDevice object to connect to this server.
BLEClient* connectToServer(BLEAdvertisedDevice* device) {
BLEClient* pClient = BLEDevice::createClient();
if (pClient->connect(device)){ // Connect to the remote BLE Server.
Serial.println(" - Connected to server");
return pClient;
}
else{
Serial.println("Failed to Connect to device");
return NULL;
}
}
Use following line to call this connect function, it return the client object which can be used to disconnect from server.
if(deviceFound==true){
BLEClient* myDevice = connectToServer(device);
if(myDevice!=NULL){
Serial.print("Connected to the BLE Server: ");
Serial.println(device->getName().c_str());//print name of server
//DO SOME STUFF
//disconnect the device
myDevice->disconnect();
Serial.println("Device disconnected.");
}
}
This was the client side.
At server side to set the connection status flag use the following:
//Setup callbacks onConnect and onDisconnect
class MyServerCallbacks: public BLEServerCallbacks {
void onConnect(BLEServer* pServer) {
Serial.println("Client Connected");
deviceConnected = true;
};
void onDisconnect(BLEServer* pServer) {
Serial.println("Client Disconnected");
deviceConnected = false;
}
};

Data loss during communication via car's CAN bus (Arduino Uno + MCP2515)

I am very new to Arduino and this is my very first topic here. I am currently working on car's CAN BUS (500,000bps) communication in order to read and translate the CAN message real time. The UNO together with MCP2515 are connected to the car OBD2 port in order to sniff all supported PID data and the available output are now printed out and it looks promising enough (attached picture). However, I experienced frequent data loss, even though there is the delay of 5 seconds to read the next loop of data. I did try searching but never get any closer to the proper solution. Is this situation is called either Race Condition or data overflow? or I have to take a look at buffer size of transmitted data?
All source file and sketch are referred to https://github.com/sandeepmistry/arduino-OBD2.
Here is the sketch I used (libraries\OBD2-0.0.1\examples\OBD2_01_SupportedPIDs);
Please see the result of printout attached.
[#include <CAN.h> // the OBD2 library depends on the CAN library
#include <OBD2.h>
void setup() {
Serial.begin(9600);
while (!Serial);
Serial.println(F("OBD2 data printer"));
while (true) {
Serial.print(F("Attempting to connect to OBD2 CAN bus ... "));
if (!OBD2.begin()) {
Serial.println(F("failed!"));
delay(1000);
} else {
Serial.println(F("success"));
break;
}
}
Serial.println();
Serial.print("VIN = ");
Serial.println(OBD2.vinRead());
Serial.print("ECU Name = ");
Serial.println(OBD2.ecuNameRead());
Serial.println();
}
void loop() {
// loop through PIDs 0 to 95, reading and printing the values
for (int pid = 0; pid < 96; pid++) {
processPid(pid);
}
Serial.println();
// wait 5 seconds before next run
delay(5000);
}
void processPid(int pid) {
if (!OBD2.pidSupported(pid)) {
// PID not supported, continue to next one ...
return;
}
// print PID name
Serial.print(OBD2.pidName(pid));
Serial.print(F(" = "));
if (OBD2.pidValueRaw(pid)) {
// read the raw PID value
unsigned long pidRawValue = OBD2.pidReadRaw(pid);
Serial.print(F("0x"));
Serial.print(pidRawValue, HEX);
} else {
// read the PID value
float pidValue = OBD2.pidRead(pid);
if (isnan(pidValue)) {
Serial.print("error");
} else {
// print value with units
Serial.print(pidValue);
Serial.print(F(" "));
Serial.print(OBD2.pidUnits(pid));
}
}
Serial.println();
}][1]
Printout of sketch OBD2_03_DataPrinter.ino
Upgrading from a UNO to a Mega2560 solved my problems. Now my sketches upload much faster and the frequent crashes have disappeared. Clearly, the UNO has insufficient memory to cope with a can-bus shield.

How to have multiple connections to a Arduino webserver?

I have an Arduino running a webserver that is receiving data every 2 seconds. I CAN connect to its IP address by typing into the browser. I also created a web app that pulls data from this IP address every time new data comes in. The issue is that I need to access the IP address with the web app while another program is accessing it. Currently only one program can access at a time. I would like to have a Python script pulling data from the IP address constantly and still allow the web app to connect to view it live. How can I achieve this?
Arduino code with a lot of other stuff removed...
WiFiServer server(80); //server socket
WiFiClient client_1 = server.available();
void setup() {
Serial.begin(9600);
enable_WiFi(); // function to enable wifi
connect_WiFi(); // function to connect to wifi
server.begin();
}
void loop() {
client_1 = server.available();
if (client_1) {
printWEB(client_1); // this posts the data as text to the web IP address
}
delay(2000);
}
void printWEB(WiFiClient client) {
if (client) { // if you get a client,
Serial.println("new client"); // print a message out the serial port
String currentLine = ""; // make a String to hold incoming data from the client
while (client.connected()) { // loop while the client's connected
if (client.available()) { // if there's bytes to read from the client,
char c = client.read(); // read a byte, then
Serial.write(c); // print it out the serial monitor
if (c == '\n') { // if the byte is a newline character
// if the current line is blank, you got two newline characters in a row.
// that's the end of the client HTTP request, so send a response:
if (currentLine.length() == 0) {
// HTTP headers always start with a response code (e.g. HTTP/1.1 200 OK)
// and a content-type so the client knows what's coming, then a blank line:
client.println("HTTP/1.1 200 OK");
client.println("Access-Control-Allow-Origin: *");
client.println("Access-Control-Allow-Methods: GET");
client.println("Content-type: application/json");
client.println();
moistureReading = analogRead(A1);
tmpString = dataPosted;
tmpString.replace("%moistureData%", String(moistureReading) );
client.flush();
client.print( tmpString );
// The HTTP response ends with another blank line:
client.println();
// break out of the while loop:
break;
}
else { // if you got a newline, then clear currentLine:
currentLine = "";
}
}
else if (c != '\r') { // if you got anything else but a carriage return character,
currentLine += c; // add it to the end of the currentLine
}
}
}
// close the connection:
client.stop();
Serial.println("client disconnected");
}
}
The solution here was to take the delay off of the arduino code by simply removing the sleep function (Turns out this is not required). I then had to create a delay in all of my fetching codes. The React.js needed a sleep function and the python script needed a sleep function. This allows the two platforms to collect data from the same IP Address simultaneously. I needed a minimum of about 5-10 second sleep for both apps in order for this to work. I initially tried 1 second for each and it didn't work.
The webserver as programmed on your Arduino can only serve one request from a client at a time, not two simultaneously.
If two clients are doing requests in a loop, and are doing that fairly quickly, there will be situations where one client is blocking access for the other.
Try making the two clients much slower, i.e. retrieve information at a much lower frequency, just to see if the Arduino can keep up then.
Also, make the webserver on the Arduino as fast as possible, and call it as often as possible.
So, don't put delay()s in the loop, or anywhere else, and try to do the analogread() and the return string preparation outside of the webserver code and in the loop() every x seconds using millis(), so as little time as possible is spent in the webserver code.

Unable to store stream data in variable in Arduino programming

I'm unable to store the serial.port value in a variable. I want to send a message from Android telnet app, on and off. If on comes I want to print fan on, if off comes I want to print off. I'm able to print on and off while I'm statically fixing value. I'm unable to store the stream in a variable.
String stringOne;
void setup() {
digitalWrite(13, LOW);
// Open serial communications and wait for port to open:
Serial.begin(9600);
while (!Serial) {
; // wait for serial port to connect. Needed for native USB port only
}
// send an intro:
Serial.println("\n\nString substring():");
Serial.println();
pinMode(13,OUTPUT);
}
void loop() {
digitalWrite(13,LOW);
// Set up a String:
stringOne ="+IPD 0,14 :ON";
int length = stringOne.length();
Serial.println(stringOne.length());
Serial.println(stringOne);
if (Serial.available() > 0) {
// substring(index) looks for the substring from the index position to the end:
if (stringOne.substring(length-2,length) == "ON") {
Serial.println("FAN ON");
digitalWrite(13,HIGH);
// delay(2000);
}
if (stringOne.substring(length-3,length) == "OFF") {
Serial.println("FAN OFF");
digitalWrite(13,LOW);
// delay(2000);
}
}
// you can also look for a substring in the middle of a string:
// do nothing while true:
while (true);
}
Well, while editing your question, I couldnt help noticing that infinite loop at the end of your code.
// do nothing while true:
while(true)
In this case, even if your code was all right, you cant expect to get next data.
void loop --> Remember it is itself a infinite loop
update 1:
your logic to use the serial port is wrong;
Remember, serial port only recieves a single character at a time.
if you send "hello" from pc, at the other end, arduino will recieve h, e, l, l, o
The trick is to collect all letters into a array. and then use our logic in it.
char commandbuffer[20]; //an array to hold our characters
int i=0;
if (Serial.available() > 0) {
while( Serial.available() >0) { //read until all data we send arrives
char c = Serial.read();
commandbuffer[i]= c; //we are actually storing it one by one
i++;
}
}
commandbuffer[i]='\n';
for(int j = 0; j<i; j++){
Serial.print(commandbuffer[j]);// and show it one by one too
}
now when you send "hello", it will print hello back. I hope this give you some idea. Happy coding.

Initializing Xbee S1 by an Arduino mini pro

I am trying to configurate my XBee module by an Arduino pro mini that is connected to my computer by de FTDI basic from sparkfun.
I already can write and send data from the Xbee to another Xbee module by the Arduino.
My problem is that I want to configure the Xbee by the arduino. I am sending ‘+++’ with the arduino to my Xbee and want to receive the ‘OK’ from the Xbee with the serial monitor from the arduino editor. The problem is that I can send it but never receive and ‘OK’, and when I am trying to configure the Xbee the configuration never happened. So I cant reach the Xbee command line.
uint8_t pinRx = 0, pinTx = 1; //Initialise pins on the Arduino
char GotChar;
long BaudRate = 4800;
int incomingByte=0;
SoftwareSerial mySerial( pinRx , pinTx ); //Initialise SoftwareSerial
void init_USB()
{
Serial.begin(BaudRate);
Serial.println("Start");
mySerial.begin(BaudRate);
}
void init_XBee()
{
Serial.begin(9600);
int check = 0;
while(T_XBEE_CONTROLLER_CheckOK() == 0)
{
Serial.println("CheckOK");
Serial.write("+++");
delay(2000);
}
Serial.println("ATCH 8\r");
delay(2000);
Serial.write("ATID 1234\r");
delay(2000);
Serial.write("+++");
delay(2000);
Serial.write("ATPL 0\r");
delay(2000);
Serial.write("+++");
delay(2000);
Serial.write("ATAP 2\r");
delay(2000);
}
int T_XBEE_CONTROLLER_CheckOK()
{
char ch[2];
ch[0] = 0x00;
while(! ((ch[0] == 'O' ) && (ch[1] == 'K') ))
{
ch[0] = mySerial.read();
ch[1] = mySerial.read();
if((ch[0] != 'O') && (ch[1] != 'K') && (ch[2] != '\r'))
{
Serial.println("FAILED");
return 0;
}
Serial.println("SUCCES");
return 1;
}
return 0;
}
it is a stupid answer but first of all, you should check that your Xbee is configured as AT device instead of API device. If it is API mode, the module wont understand the messages.
To do that you just have to use X-CTU application and read the configuration of the module, and change it to AT device.
Hope that helps.
Thanks for the response and the help, and also sorry for the late response.
I already solved the problem. The problem was the function write(). If you want to reach the command mode from the XBee you should only send "+++". If there is some kind of character behind the "+++" you can't reach the command line. The function write put a (for me) unknown character behing the "+++". So that's the problem for not reaching the command line.
To resolve this problem just use the function print("+++"). After using this function it is possible to reach the command line.
You have to read from the serial right after you send the +++ command, because this is where the xbee writes 'OK'. Also a better way to respect the guard times is to wait for a reply, and test to see if it is 'OK'.
Here is my code, I don't remember if it was working the last time I checked but I will just paste it here and you can modify it as you like. All it does is broadcast A1, B2, C3, etc.
There's a lot of commenting out where I was experimenting, but the regular comments are informative. Make sure you go through it step by step, it's quite simple when you get your head around it. Don't forget to change the destination address low to 0xFFFF if you want to broadcast.
In the end you'll come to the same realisation I did that AT mode is not suitable for configuring the xbee by writing programs.
For example I had an xbee constantly transmitting the number '2', and when another xbee was entering command mode using this code, it would receive the number 2 from the remote xbee when it should have received the 'OK' message from the local xbee, thus the program didn't acknowledge it being in command mode and breaking. When entering command mode you'd think an xbee would turn it's receiver off, but that's not the case so you can easily get into trouble.
If you want to do it the right way, have a look at API mode. I have series 1 xbee's so I'm implementing the Digimesh protocol, which so far I haven't seen anyone online do, but it's almost identical to the Zigbee so it's easy. If you'd like I can give you my code for that which can serve as a simple example.
/*
unicast_configure
Configure an XBee for unicast transmission and transmit
some characters to test
*/
#include <SoftwareSerial.h>
// Pins on Bees Shield:
SoftwareSerial xbee(2, 3); // TX, RX
boolean configured;
char c = 'A';
boolean configureRadio() {
// Set the data rate for the SoftwareSerial port:
xbee.begin(9600);
// Put the radio in command mode:
Serial.write("Entering command mode\r");
delay(1000);
while(xbee.available()>0) {xbee.read();}
xbee.write("+++");
while(xbee.available()>0) {xbee.read();}
//delay(1000);
//while(xbee.available() > 0) {Serial.write(xbee.read());}
String ok_response = "OK\r"; // The response we expect
// Read the text of the response into the response variable
// This satisfies the guard time by waiting for the OK message
String response = String("");
while (response.length() < ok_response.length()) {
if (xbee.available() > 0) {
response += (char) xbee.read();
}
}
Serial.println("response1: " + response);
// If we got received OK, configure the XBee and return true:
if (response.equals(ok_response)) {
Serial.println("Enter command mode successful");
// Restore to default values:
Serial.println("Restoring default values before making changes");
xbee.write("ATRE\r");
Serial.println("Setting addr high");
xbee.write("ATDH0\r"); // Destination high
//while(xbee.available() > 0) {Serial.write(xbee.read());}
Serial.println("Setting addr low");
xbee.write("ATDL1\r"); // Destination low-REPLACE THIS
//while(xbee.available() > 0) {Serial.write(xbee.read());}
Serial.println("Setting MY address");
xbee.write("ATMYFFFF\r");
// Apply changes:
Serial.println("Applying changes");
xbee.write("ATAC\r");
/*
///////////////////////////////////////////////
// Write to non-volatile memory:
// Use similar technique as above to satisfy guard time
Serial.write("Saving\r");
xbee.write("ATWR\r");
String response2 = String("");
//while (xbee.available() > 0) {Serial.write(xbee.read());}
while (response2.length() < ok_response.length()) {
if (xbee.available() > 0) {
response2 += (char) xbee.read();
}
}
Serial.println("response2: " + response2);
if (response2.equals(ok_response)) {
Serial.println("Save successful");
}
else { Serial.println("Save not successful");
return false;
}
// And reset module:
Serial.println("Resetting");
xbee.write("ATFR\r");
///////////////////////////////////////////////
*/
Serial.write("Exit command mode\r");
xbee.write("ATCN\r"); // Exit command mode
//while(xbee.available() > 0) {Serial.write(xbee.read());}
Serial.write("Finished\r");
return true;
} else {
return false; // This indicates the response was incorrect
}
}
void setup() {
Serial.begin(9600); // Begin serial
configured = configureRadio();
}
void loop() {
// Test transmission:
if (configured) {
xbee.print(c);
Serial.print(c);
c = c + 1;
if (c > 'Z') { c = 'A'; }
}
else {
Serial.println("Not configured (in loop)");
delay(5000);
Serial.println("Retrying configuration");
configured = configureRadio();
}
delay(1500);
}

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