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in the below code write is working fine, but read is failing ( 404 error) can you please help me reslove this.
/*
Go to thingspeak.com and create an account if you don't have one already.
After logging in, click on the "New Channel" button to create a new channel for your data. This is where your data will be stored and displayed.
Fill in the Name, Description, and other fields for your channel as desired, then click the "Save Channel" button.
Take note of the "Write API Key" located in the "API keys" tab, this is the key you will use to send data to your channel.
Replace the channelID from tab "Channel Settings" and privateKey with "Read API Keys" from "API Keys" tab.
Replace the host variable with the thingspeak server hostname "api.thingspeak.com"
Upload the sketch to your ESP32 board and make sure that the board is connected to the internet. The ESP32 should now send data to your Thingspeak channel at the intervals specified by the loop function.
Go to the channel view page on thingspeak and check the "Field1" for the new incoming data.
You can use the data visualization and analysis tools provided by Thingspeak to display and process your data in various ways.
Please note, that Thingspeak accepts only integer values.
You can later check the values at https://thingspeak.com/channels/2005329
Please note that this public channel can be accessed by anyone and it is possible that more people will write their values.
*/
#include <WiFi.h>
const char *ssid = "xxxx"; // Change this to your WiFi SSID
const char *password = "xxxxx"; // Change this to your WiFi password
const char *host = "api.thingspeak.com"; // This should not be changed
const int httpPort = 80; // This should not be changed
const String channelID = "2805914"; // Change this to your channel ID
const String writeApiKey = "xxxxxxxxxxxxxxxx"; // Change this to your Write API key
const String readApiKey = "xxxxxxxxxxxxxxxx"; // Change this to your Read API key
// The default example accepts one data filed named "field1"
// For your own server you can ofcourse create more of them.
int field1 = 20;
//int field1 = 20;
int numberOfResults = 1; // Number of results to be read
int fieldNumber = 1; // Field number which will be read out
void setup() {
Serial.begin(115200);
while (!Serial) {
delay(100);
}
// We start by connecting to a WiFi network
Serial.println();
Serial.println("******************************************************");
Serial.print("Connecting to ");
Serial.println(ssid);
WiFi.begin(ssid, password);
while (WiFi.status() != WL_CONNECTED) {
delay(500);
Serial.print(".");
}
Serial.println("");
Serial.println("WiFi connected");
Serial.println("IP address: ");
Serial.println(WiFi.localIP());
}
void readResponse(NetworkClient *client) {
unsigned long timeout = millis();
while (client->available() == 0) {
if (millis() - timeout > 5000) {
Serial.println(">>> Client Timeout !");
client->stop();
return;
}
}
// Read all the lines of the reply from server and print them to Serial
while (client->available()) {
String line = client->readStringUntil('\r');
Serial.print(line);
}
Serial.printf("\nClosing connection\n\n");
}
void loop() {
NetworkClient client;
String footer = String(" HTTP/1.1\r\n") + "Host: " + String(host) + "\r\n" + "Connection: close\r\n\r\n";
// WRITE --------------------------------------------------------------------------------------------
if (!client.connect(host, httpPort)) {
return;
}
client.print("GET /update?api_key=" + writeApiKey + "&field1=" + field1 + footer);
readResponse(&client);
delay(200);
// READ --------------------------------------------------------------------------------------------
String readRequest = "GET /channels/" + channelID + "/fields/" + fieldNumber + ".json?results=" + numberOfResults + " HTTP/1.1\r\n" + "Host: " + host + "\r\n"
+ "Connection: close\r\n\r\n";
if (!client.connect(host, httpPort)) {
return;
}
client.print(readRequest);
readResponse(&client);
// -------------------------------------------------------------------------------------------------
//++field1;
delay(10000);
}
Hello Everyone,
I'm running an IoT project at my university using a free . Basically, my system uploads the sensor data to 4 different fields of a ThingSpeak channel and I'm reading from or writing to the channel through Simulink. I have a few questions regarding this topic:
- I'm trying to upload to the server every 3 seconds (which seemed to be providing the best results so far). Since the channel only accepts data transmit every 15 seconds, what is the optimized upload interval rate to match the interval rate of the channel? Because otherwise I have realized that my interval rate can go up to 1min sometimes for some reason.
- Is reading from/writing to the channel through simulink while the system is uploading data to the channel slow down th whole process? What is your overall suggestion in this case?
I'm excited to hear your suggestions and experiences!
Regards,
Ege
Hello!
I`ve got problems with reading last input of a channel field using AT commands, here follows the sketch I'm currently using:
/* String tx_data_r = "GET https://api.thingspeak.com/channels/CHANNEL/fields/4/last.txt?api_key=API_READ_KEY&results=1"; */
String tx_data_r = "GET https://api.thingspeak.com/channels/"; tx_data_r += "CHANNEL"; tx_data_r += "/"; tx_data_r += "fields"; tx_data_r += "/4/"; tx_data_r += "last.txt?api_key="; tx_data_r += "API_READ_KEY"; tx_data_r += "&results=1"; tx_data_r += "\r\n";
Serial.print("AT+CIPSEND=");
delay(1000);
Serial.println(tx_data_r.length()); delay(1000);
Serial.println(tx_data_r); delay(1000);
This piece of code doesn`t return a valid response, however if I copy/paste https://api.thingspeak.com/channels/CHANNEL/fields/4/last.txt?api_key=API_READ_KEY&results=1" using a browser I get the right data.
One more thing, if instead of using a microcontroller I use an USB serial PC interface program directly connected to my RF module, with GET https://api.thingspeak.com/channels/CHANNEL/fields/4/last.txt?api_key=API_READ_KEY&results=1 along with other commands I get the right data too!
Can anybody tell me what's going on?
There are no problems with any read related commands.
If a working sketch is available it will be most welcome!
Tks in advance for any help!
