How to read data from ThingSpeak and control led using sim800L?

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Su Kyi
Su Kyi 2020-12-15
评论： Anzaku Engla 2023-4-27
I'm working on SIM800L with arduino and try to read data from ThingSpeak. I can read my channel field last value (1 or 0) using AT+HTTPREAD command. But the content get from sim800L.read() is -1 not one or zero. I want to read 1 or 0 and then turn on/off LED. How to get the data of field from the response of AT+HTTPREAD? Please find the code as follows:
{.....
SIM800L.println("AT+HTTPPARA=\"URL\",\"http://api.thingspeak.com/channels/xxxxxxx/fields/3/last?api_key=xxxxxxxxxxxxxx\"");
delay(1000);
ShowSerialData();
SIM800L.println("AT+HTTPACTION=0");
delay(10000);
ShowSerialData();
SIM800L.println("AT+HTTPREAD");
delay(300);
ShowSerialData();
changeled();
ShowSerialData();
SIM800L.println("");
delay(100);
}
void changeled()
{
String content = "";
Serial.println(SIM800L.read());
content = content + String(SIM800L.read());
Serial.print("Content:");
Serial.println(content);
}
  3 个评论
显示 1更早的评论
Christopher Stapels
Christopher Stapels 2022-10-14
-1 is for unauthorized. Perhaps it is a private channel you are trying to read?
Anzaku Engla
Anzaku Engla 2023-4-27
First of all you have to be sure you can read AT command reply from the SIM800 first. If you can do this your solution is close

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回答（1 个）

Vinod
Vinod 2021-9-21
编辑：Vinod 2021-9-21
Is the SIM card activated? Have you confirmed that you can connect to the internet with the SIM800L module and your SIM card? Does your GSM provider support the use of their SIM card in the SIM800L module? See this video.

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