[SOLVED] Rare Spark Core connection problem

IoT Devices
1

Just a little note for those using a Spark Core. There is a know issue with the TI WiFi modem where on some slow networks the DNS server is not set up correctly. Simple to solve instead of

request.hostname = "things.ubidots.com";

Use

IPAddress ubidotsIP = (50,23,124,68);
request.ip = ubidotsIP;

Enjoy, and let’s hope your IP address does not change anytime soon.

2

For reason I do not understand it appears that the solution above does not work either. You need

byte ubidotsIP[] = { 50,23,124,68 };
request.ip = ubidotsIP;

3

Thanks @Howard Indeed, there’s a known issue with some Sparks not doing DNS resolution. Here’s the code that solved it for us:

#include "dnsclient/dnsclient.h"
#include "HttpClient/HttpClient.h"

HttpClient http;
char resultstr[64];
float value = 0.0;

#define VARIABLE_ID "5499ba207625421efc176fdc"
#define TOKEN "j2aawKrPRmPRszEbwauSlnJEA2xxxx"


http_header_t headers[] = {
    { "Host", "things.ubidots.com" },           
    { "Content-Type", "application/json" },
    { "X-Auth-Token" , TOKEN },
    { NULL, NULL }                              
};

http_request_t request;
http_response_t response;

IPAddress dnsServerIP(8,8,8,8);
IPAddress remote_addr;
DNSClient dns;
char serverName[] = "things.ubidots.com";

void setup() {     
    request.port = 80;
    dns.begin(dnsServerIP);
    dns.getHostByName(serverName, remote_addr);
    request.ip = remote_addr;
    request.path = "/api/v1.6/variables/"VARIABLE_ID"/values";
    Serial.begin(9600);
}

void loop() {     
    value++;
    sprintf(resultstr, "{\"value\":%.4f}", value);
    request.body = resultstr;
    http.post(request, response, headers);
    Serial.println(response.status); 
    Serial.println(response.body);
}

This code uses some kind of internal DNS server inside the Spark, which can be seen in this line:

IPAddress dnsServerIP(8,8,8,8);