Arduino Uno with Adafruit CC3000

Question

I am using Arduino Uno with Adafruit CC3000 wifi shield to connect to the internet and get data for Arduino. Everything works fine but I can't figure out how to use HttpClient library. The code is:

#include <Adafruit_CC3000.h>
#include <SPI.h>
#include "utility/debug.h"
#include "utility/socket.h"
#include <HttpClient.h>
#define ADAFRUIT_CC3000_IRQ 3 
#define ADAFRUIT_CC3000_VBAT 5
#define ADAFRUIT_CC3000_CS 10
Adafruit_CC3000 cc3000 = Adafruit_CC3000(ADAFRUIT_CC3000_CS, ADAFRUIT_CC3000_IRQ, ADAFRUIT_CC3000_VBAT,SPI_CLOCK_DIVIDER);
#define WLAN_SSID "ssid" 
#define WLAN_PASS "pwd"
#define WLAN_SECURITY WLAN_SEC_WPA2
void setConnection(){
 Serial.println("Initializing...");
 if (!cc3000.begin())
 {
 Serial.println("Couldn't begin()! Check your wiring?");
 while(1);
 }
 Serial.print("Attempting to connect to ");
 Serial.println(WLAN_SSID);
 if (!cc3000.connectToAP(WLAN_SSID, WLAN_PASS, WLAN_SECURITY)) {
 Serial.println("Failed!");
 while(1);
 } 
 Serial.println("Connected!"); 
 Serial.println(F("Request DHCP"));
 while (!cc3000.checkDHCP())
 {
 delay(100);
 } 
 Serial.println(F("DHCP success!!"));
 }
void dweet(){
 int ctr=0;
 char buff[100];
 int x=0;
 const char* host = "https://dweet.io/get/latest/dweet/for/dunebot";
 Serial.println(F("Initializing dweet client ..."));
 HttpClient client;
 client.get(host);
 Serial.println(F("Client Connected !"));
 while (client.available()) {
 char c = client.read();
 Serial.write(c);
 delay(100);
 }
void setup(){
 Serial.begin(115200); 
 while(!Serial); 
 Serial.print("Free RAM: "); Serial.println(getFreeRam(), DEC);
 setConnection();
}
void loop(){
dweet(); 
}

If all worked fine then I should have got a json string which is:

{"this":"succeeded","by":"getting","the":"dweets","with":[{"thing":"dunebot","created":"2018-05-12T13:27:56.106Z","content":{"0001":""}}]}

When I run the code, Arduino connects to the wifi network but afterwards when I observe the Serial monitor all I get are garbage values.

enter image description here

I need a way to read the key 0001 from the json string. Any help would be appreciated.Thanks.

Answer 1

The HttpClient object must be instantiated with a Client object which will handle the underlying connection. Source:

Requires a networking hardware and a library that provides transport specific Client instance, such as:

Refer to the following code:

• https://github.com/arduino-libraries/ArduinoHttpClient/blob/master/examples/DweetGet/DweetGet.ino
• https://github.com/adafruit/Adafruit_CC3000_Library/blob/master/Adafruit_CC3000.h#L86
• https://github.com/arduino-libraries/ArduinoHttpClient/blob/master/src/HttpClient.h#L51

In the above example, it is done like

WiFiClient wifi;
HttpClient client = HttpClient(wifi, serverAddress, port);

Which means that for your code, you might want to pull out client as global object and instantiate it as:

Adafruit_CC3000 cc3000 = Adafruit_CC3000(ADAFRUIT_CC3000_CS, ADAFRUIT_CC3000_IRQ, ADAFRUIT_CC3000_VBAT,SPI_CLOCK_DIVIDER);
/* Create new Adafruit_CC3000_Client object */
Adafruit_CC3000_Client cc3000_client;
/* Feed this into the client */
HttpClient client (cc3000_client, "dweet.io", 80);

You should also use the example code to see how to print the response after executing client.get():

 // read the status code and body of the response
 statusCode = client.responseStatusCode();
 response = client.responseBody();
 Serial.print("Status code: ");
 Serial.println(statusCode);
 Serial.print("Response: ");
 Serial.println(response);

The example code is pretty much example what you want, you just have to give it a Adafruit_CC3000_Client as the Client.

Full code:

#include <Arduino.h>
#include <Adafruit_CC3000.h>
#include <SPI.h>
#include "utility/debug.h"
#include "utility/socket.h"
#include <HttpClient.h>
#define ADAFRUIT_CC3000_IRQ 3
#define ADAFRUIT_CC3000_VBAT 5
#define ADAFRUIT_CC3000_CS 10
Adafruit_CC3000 cc3000 = Adafruit_CC3000(ADAFRUIT_CC3000_CS, ADAFRUIT_CC3000_IRQ, ADAFRUIT_CC3000_VBAT,SPI_CLOCK_DIVIDER);
/* Create new Adafruit_CC3000_Client object */
Adafruit_CC3000_Client cc3000_client;
/* Feed this into the client */
HttpClient client (cc3000_client, "dweet.io", 80);
#define WLAN_SSID "ssid"
#define WLAN_PASS "pwd"
#define WLAN_SECURITY WLAN_SEC_WPA2
int statusCode = 0;
String response;
void setConnection(){
 Serial.println("Initializing...");
 if (!cc3000.begin())
 {
 Serial.println("Couldn't begin()! Check your wiring?");
 while(1);
 }
 Serial.print("Attempting to connect to ");
 Serial.println(WLAN_SSID);
 if (!cc3000.connectToAP(WLAN_SSID, WLAN_PASS, WLAN_SECURITY)) {
 Serial.println("Failed!");
 while(1);
 }
 Serial.println("Connected!");
 Serial.println(F("Request DHCP"));
 while (!cc3000.checkDHCP())
 {
 delay(100);
 }
 Serial.println(F("DHCP success!!"));
}
void dweet(){
 int ctr=0;
 char buff[100];
 int x=0;
 const char* host = "https://dweet.io/get/latest/dweet/for/dunebot";
 Serial.println(F("Initializing dweet client ..."));
 client.get(host);
 Serial.println(F("Client Connected !"));
 // read the status code and body of the response
 statusCode = client.responseStatusCode();
 response = client.responseBody();
 Serial.print("Status code: ");
 Serial.println(statusCode);
 Serial.print("Response: ");
 Serial.println(response);
 /*
 Typical response is:
 {"this":"succeeded",
 "by":"getting",
 "the":"dweets",
 "with":[{"thing":"my-thing-name",
 "created":"2016-02-16T05:10:36.589Z",
 "content":{"sensorValue":456}}]}
 You want "content": numberValue
 */
 // now parse the response looking for "content":
 int labelStart = response.indexOf("content\":");
 // find the first { after "content":
 int contentStart = response.indexOf("{", labelStart);
 // find the following } and get what's between the braces:
 int contentEnd = response.indexOf("}", labelStart);
 String content = response.substring(contentStart + 1, contentEnd);
 Serial.println(content);
 //There was a missing brace here. Was the code cut off?!
}
void setup(){
 Serial.begin(115200);
 while(!Serial);
 Serial.print("Free RAM: "); Serial.println(getFreeRam(), DEC);
 setConnection();
}
void loop() {
 dweet();
}

• codedump: So i did what you told but it throws an error no matching function for call to 'HttpClient::HttpClient(Adafruit_CC3000&, const char [9], int)'. Does HttpClient work with Adafruit cc3000?
• Maximilian Gerhardt: @AshishKafle in the library code I linked it says that it derives from the class Client. I will test this my self in just a moment.
• Maximilian Gerhardt: @AshishKafle Could you retry that again. I referenced the Adafruit_CC3000 class when it should have been the Adafruit_CC3000_Client class.
• codedump: the code works nice but after Serial.println(F("Client Connected !")); nothing seems to work for me. After that i get nothing.
• Maximilian Gerhardt: Could you try this sketch and post the output on pastebin. pastebin.com/2kUqACgB