This program is a simple "challenge-response" sketch.

It is setup to communicate to a modem over a SoftwareSerial line at 9600bps.

The sketch is extensively tested with a SIM7000 modem.

There are two example functions to send restAPI requests to a remote server. The functions restAPIget and restAPIpost are located in the tab's with the same name. You can execute the functions by entering getapi or postapi in the command prompt (the input line in the Arduino Serial Monitor).

You have to tailer these functions for your specific needs.

===> GETAPI
getRestAPI ..
---> AT+CSQ
<--- AT+CSQ
+CSQ: 24,99
OK
---> AT+SAPBR=1,1
<--- AT+SAPBR=1,1
ERROR
---> AT+HTTPTERM
<--- AT+HTTPTERM
ERROR
---> AT+HTTPINIT
<--- AT+HTTPINIT
OK (true state)
---> AT+HTTPPARA="URL","http://httpbin.org/get"
<--- AT+HTTPPARA="URL","http://httpbin.org/get"
OK (true state)
---> AT+HTTPPARA="CID",1
<--- AT+HTTPPARA="CID",1
OK (true state)
---> AT+HTTPACTION=0
<--- AT+HTTPACTION=0
OK
+HTTPACTION: 0,200,255 (true state)
---> AT+HTTPREAD=0,500
<--- AT+HTTPREAD=0,500
+HTTPREAD: 255
{
  "args": {},
  "headers": {
    "Accept": "*/*",
    "Host": "httpbin.org",
    "User-Agent": "SIMCOM_MODULE",
    "X-Amzn-Trace-Id": "Root=1-60b3633d-4a9d49f801e25839122b33bb"
  },
  "origin": "18.197.48.88",
  "url": "http://httpbin.org/get"
}
OK (true state)
---> AT+HTTPTERM
<--- AT+HTTPTERM
OK
==>> Done..

===> POSTAPI
postRestAPI ..
---> AT+CSQ
<--- AT+CSQ
+CSQ: 24,99
OK
---> AT+HTTPINIT
<--- AT+HTTPINIT
OK (true state)
---> AT+HTTPPARA="URL","http://httpbin.org/post"
<--- AT+HTTPPARA="URL","http://httpbin.org/post"
OK (true state)
---> AT+HTTPPARA="CID",1
<--- AT+HTTPPARA="CID",1
OK (true state)
---> AT+HTTPPARA="CONTENT","application/json"
<--- AT+HTTPPARA="CONTENT","application/json"
OK (true state)
AT+HTTPDATA=17,10000
DOWNLOAD
(true state)
---> [{"simple":"json"}]
OK
---> AT+HTTPACTION=1
<--- AT+HTTPACTION=1
OK
+HTTPACTION: 1,200,432 (true state)
---> AT+HTTPREAD=0,500
<--- AT+HTTPREAD=0,500
+HTTPREAD: 432

{
  "args": {},
  "data": "{\"simple\":\"json\"}",
  "files": {},
  "form": {},
  "headers": {
    "Accept": "*/*",
    "Content-Length": "17",
    "Content-Type": "application/json",
    "Host": "httpbin.org",
    "User-Agent": "SIMCOM_MODULE",
    "X-Amzn-Trace-Id": "Root=1-60b3627f-40a256736a4e20064daaeecf"
  },
  "json": {
   "simple" "json"
  }
  "origin: "18.197.48.88",
  "url": "http://httpbin.org/post"
}
OK (true state)
---> AT+HTTPTERM
<--- AT+HTTPTERM
OK
==>> Done..

The following functions handle the "challenge-response" and can be used for your specific needs:

This function sends the string ATcommand to the modem and waits for a maximum of 1000ms for a response. If the modem sends back the string "OK" the function exits immediately with a returncode "1". If the modem sends back the string "ERROR" the function exits immediately with a returncode "-1". If the modem does not send a response the function times-out (returncode "0").

This function sends the string ATcommand to the modem and waits for a maximum of waitTimems for a response. If the modem sends back the string "OK" the function exits immediately with a returncode "1". If the modem sends back the string "ERROR" the function exits immediately with a returncode "-1". If the modem does not send a response the function times-out (returncode "0").

This function sends the string ATcommand to the modem and waits for a maximum of waitTimems for a response. If the modem sends back the string OKstring the function exits immediately with a returncode "1". If the modem sends back the string ERRORstring the function exits immediately with a returncode "-1". If the modem does not send a response the function times-out (returncode "0").

This function waits 50ms for chars send by the modem and prints them.

This function waits waitTimems for chars send by the modem and prints them.

This function checks waitTimems for chars send by the modem and prints them. if the modem sends the OKstring the function exits immediately with returncode "1". if the modem sends the ERRORstring the function exits immediately with returncode "-1". If neither is received before waitTimems the function exits with returncode "0".