Hi guys,
One way of posting multiple data at once is bulk-write JSON Data. There is an example re this here, which shows how to update the data on ESP8266 frequently. I can't work out step 8, which expalins how to update the JSON file. Could you please provide me a reference/tutorial/manual so that I can upskill myself to work this out?
Also, I need to send the temperature readings (variables). Do I need to define the temp data as object or array on JSON?
Below provides the code for step 8.
// Updates the josnBuffer with data
void updatesJson(char* jsonBuffer){
/* JSON format for updates paramter in the API
* This examples uses the relative timestamp as it uses the "delta_t". You can also provide the absolute timestamp using the "created_at" parameter
* instead of "delta_t".
* "[{\"delta_t\":0,\"field1\":-70},{\"delta_t\":3,\"field1\":-66}]"
*/
// Format the jsonBuffer as noted above
strcat(jsonBuffer,"{\"delta_t\":");
unsigned long deltaT = (millis() - lastUpdateTime)/1000;
size_t lengthT = String(deltaT).length();
char temp[4];
String(deltaT).toCharArray(temp,lengthT+1);
strcat(jsonBuffer,temp);
strcat(jsonBuffer,",");
long rssi = WiFi.RSSI();
strcat(jsonBuffer, "\"field1\":");
lengthT = String(rssi).length();
String(rssi).toCharArray(temp,lengthT+1);
strcat(jsonBuffer,temp);
strcat(jsonBuffer,"},");
// If posting interval time has reached 2 minutes, update the ThingSpeak channel with your data
if (millis() - lastConnectionTime >= postingInterval) {
size_t len = strlen(jsonBuffer);
jsonBuffer[len-1] = ']';
httpRequest(jsonBuffer);
}
lastUpdateTime = millis(); // Update the last update time
}
