Powering issues

pert · December 8, 2019, 11:49pm

There's some information on GSM communication issues caused by power on the MKR GSM 1400 here that might be relevant to your situation:

github.com/arduino-libraries/MKRGSM

MKRGSM library not reliable

opened 08:24PM - 20 Nov 18 UTC

alanoatwork

type: imperfection

I've posted this before, but I'll try again. My code is pretty simple. I check f…or SMS messages and then reply back using Hologram's network. I'm using the latest MKRGSM library 1.3.1. I also have a 1400 mAhr lithium battery connected so I'm confident that I don't have a hardware issue related to modem current. Here's my code: ``` #include <MKRGSM.h> const char PINNUMBER[] = " "; const char GPRS_APN[] = "hologram"; const char GPRS_LOGIN[] = " "; const char GPRS_PASSWORD[] = " "; String HOLOGRAM_DEVICE_KEY = "********"; String HOLOGRAM_TOPIC = "_SOCKETAPI_"; GSMClient client; GPRS gprs; GSM gsm(1); // Enable debug GSM_SMS sms; GSMScanner scan; char server[] = "cloudsocket.hologram.io"; int port = 9999; boolean isSMSAvailable = false; char sms_message[145]; void setup() { Serial.begin(115200); //while(!Serial); scan.begin(); connectGSM(); } void connectGSM() { boolean connected = false; while (!connected) { Serial.println("Begin GSM Access"); if ((gsm.begin() == GSM_READY) && (gprs.attachGPRS(GPRS_APN, GPRS_LOGIN, GPRS_PASSWORD) == GPRS_READY)) { connected = true; Serial.println("GSM Access Success"); Serial.println(scan.getCurrentCarrier()); } else { Serial.println("Not connected"); delay(1000); } } } void loop() { if(Serial.available()) { char c = Serial.read(); if(c == 'e') MODEM.debug(); if(c == 'd') MODEM.noDebug(); } // Get any new incoming txt messages int c; if (sms.available()) { int i = 0; while ((c = sms.read()) != -1) { sms_message[i++] = (char)c; } sms_message[i] = '\0'; // Terminate message isSMSAvailable = true; sms.flush(); } if(gsm.isAccessAlive()) { if(gprs.status() != GPRS_READY) { if(gprs.attachGPRS(GPRS_APN, GPRS_LOGIN, GPRS_PASSWORD) == GPRS_READY) Serial.println("GPRS ready!"); else Serial.println("GRPS not ready!"); } } else { Serial.println("Reconnect to GSM..."); connectGSM(); } // Send message back through hologram if(isSMSAvailable) { isSMSAvailable = false; if (client.connect(server, port)) { client.print("{\"k\":\"" + HOLOGRAM_DEVICE_KEY + "\",\"d\":\""); client.print(sms_message); client.println("\",\"t\":\""+HOLOGRAM_TOPIC+"\"}"); client.stop(); } else { MODEM.send("AT+USOER"); } } delay(1000); }` ``` It takes anywhere from a few days to a week or more to exhibit the problem. My logs typically look like this, where the incoming SMS message, "Jdjd", gets received and then repeated back to me via Hologram's network. ``` OK AT+CMGL="REC UNREAD" +CMGL: 19,"REC UNREAD","+19495472010",,"18/11/14,03:53:24+00" Jdjd OK AT+CMGD=19 OK AT+CREG? +CREG: 0,5 OK AT+USOCR=6 +USOCR: 0 OK AT+USOCO=0,"cloudsocket.hologram.io",9999 OK AT+USOWR=0,21,"7B226B223A22433E383375242B57222C2264223A22" +USOWR: 0,21 OK AT+USOWR=0,4,"4A646A64" +USOWR: 0,4 OK AT+USOWR=0,20,"222C2274223A225F534F434B45544150495F227D" +USOWR: 0,20 OK AT+USOWR=0,2,"0D0A" +USOWR: 0,2 OK AT+USOCL=0 OK AT+CMGL="REC UNREAD" OK AT+CREG? +CREG: 0,5` ``` However, after a week or so this happens: ``` `OK AT+CMGL="REC UNREAD" +CMGL: 19,"REC UNREAD","+19495472010",,"18/11/20,19:51:00+00" JDJDJ OK AT+CMGD=19 OK AT+CREG? +CREG: 0,5 OK AT+USOCR=6 +USOCR: 0 OK AT+USOCO=0,"cloudsocket.hologram.io",9999 ERROR +UUSOCL: 0 AT+USOCL=0 ERROR AT+CMGL="REC UNREAD" OK AT+CREG? +CREG: 0,5 OK AT+CMGL="REC UNREAD" OK AT+CREG? +CREG: 0,5 ```` From then on, the library is never able to recover. Any help would be greatly appreciated. The code I submitted is a stripped down version of my application. I've been wanting to release my application using the MKRGSM board but I've been haunted by this issue. I see there's some asynchronous options that aren't well documented and I'm reluctant to use this approach - besides, shouldn't this library be rock solid as documented!

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