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5 years ago.
Compatibility with SIM900
I am developing device based on Nucleo-F401RE and SIM900 GPRS module. Now, I want to add MQTT subscribe functionality in it, and I think this code will be a good basis.
My understanding from the code, there are two steps in achieving GPRS MQTT. First, connect interface (SIM900) to network. Second, initialize MQTT client and connect to server.
I am done with first step and have successfully connect SIM900 to network (as the module get IP address). Although, I use simple AT command (illustrated by code below) to bring connection up:
//set operator apn, username, password sim900.printf("AT+CSTT=\"apn\",\"username\",\"password\"\r\n"); rcvReply(rcv,5000); DBG.printf("rspn[CSTT]:%s",rcv); //bring up wireless connection sim900.printf("AT+CIICR\r\n"); rcvReply(rcv,3000); DBG.printf("rspn[CIICR]:%s",rcv); //get local ip address sim900.printf("AT+CIFSR\r\n"); rcvReply(rcv,3000); DBG.printf("rspn[CIFSR]:%s",rcv);
Now, the problem is related initializing MQTT client and connecting it to server. If I put:
PubSubClient mqtt(serverIpAddr, port, callback);
then my program hangs. I already dig the code, and even setup debug port in PubSubClient.cpp where "PubSubClient" definition resides. However, my program didn't go in there.
- Has anybody tried this code working with either SIM900 or other GPRS module? Please give me links or explanation to do that.
- Please provide alternative library for SIM900 MQTT or SIM900 firmware that support MQTT if any.
Thanks for your time to answer my questions!
Question relating to:
5 years ago.
The code works with Arch GPRS (SIM900) to connect opensensor.io (an MQTT server). Although it's not stable.
Or you may take a look at https://developer.mbed.org/teams/ublox/code/Cellular_HelloMQTT/