Hello everyone,
I am creating a “gateway” which receives messages over LoRa and pushes them to Ubidots. The LoRa and MQTT side work reliably except for the disconnections, which give me a “+QMTSTAT: 0,1” periodically, indicating that the connection is closed by the peer. I am little confused by the terminology; for instance, does that mean the modem is closing the connection or that Ubidots is, or something else entirely? There appears to not be any problem with the cellular network, as checking Hologram during one of the disconnects shows it still live.
As of right now my solution is to just run the connection command again every 6 minutes or so, which always connects back reliably. I’d prefer not to do this forever if possible, and am wondering if anyone here has any insight into this issue. If I should be asking somewhere else please let me know!
I am using the Link.ONE WisTrio as the device, which contains an nRF52 talking serial to a BG77. The code I am using is pasted below, with some things omitted for privacy. Nothing is omitted which affects the AT commands used. Anywhere which says “PL()” is a macro for Serial.println.
#define DEBUG_DEVICE
#include "ArduinoJson-v6.21.3-custom.h"
#include <CircularBuffer.h>
#include <unordered_map>
// CONSTANTS
constexpr uint8_t BG77_POWER_KEY = WB_IO1;
// info for mqtt connection
constexpr char *SERVER = "\"169.55.61.243\""; // direct link not working as of 10/25
// constexpr char *SERVER = "\"industrial.api.ubidots.com\"";
constexpr char *PORT = "1883";
constexpr char *USERNAME = "\"API KEY OMITTED\"";
constexpr char *TOPIC = "/v1.6/devices/";
constexpr int TIME_TO_TX =
3600000; // time for gateway to send info packet to ubidots
constexpr int TIME_TO_RECONN =
420000; // time for gateway to reconnect to ubidots
// constexpr int TIME_TO_TX =
// 30000; // time for gateway to send info packet to ubidots
// lora stuff
constexpr uint32_t US_FREQ = 915000000;
constexpr uint16_t sf = 12, bw = 1, cr = 0, preamble = 8, txPower = 22;
// GLOBALS
GatewayInfo infoPacket; // info aboout gateway
CxInfoLoRa cxinfo; // packet for new lora info
Packet newData; // packet for received info
CircularBuffer<Packet, UINT8_MAX> mainDataBuff; // static queue for rx packets
unordered_map<uint16_t, time_t>
uniqueDevList; // table for amount of devices that have talked to gateway
time_t curr_tx_timer = 0; // timer for sending gateway stuff
time_t curr_reconn_timer = 0; // timer for reconnecting
bool firstBoot = true; // to use to do stuff on first boot
// FUNCTIONS
// read response from modem
String BG77_read(time_t timeout_ms) {
String resp = "";
time_t timeStamp = millis();
while ((millis() - timeStamp) < timeout_ms) {
if (Serial1.available() > 0) {
resp += (char)Serial1.read();
delay(1);
}
}
PL(resp);
return resp;
}
// write commnads to modem.
void BG77_write(const char *command) {
while (*command) {
Serial1.write(*command);
command++;
}
Serial1.println();
}
// send packet of info to ubidots
void cell_cmds(const char *jsonString, const char *id) {
// AT CMDS FOR BG77
String command = "AT+QMTPUBEX=0,0,0,0,\"";
command += TOPIC;
command += id;
command += "\",\"";
command += jsonString;
command += "\"\r";
BG77_write(command.c_str());
BG77_read(3000);
}
// generic function to send any form of struct to JSON
template <typename T> void send_to_cell(T infoPacket) {}
template <> void send_to_cell<GatewayInfo>(const GatewayInfo infoPacket) {
StaticJsonDocument<256> infoJSON;
infoJSON["eui"] = infoPacket.node_id;
infoJSON["r"] = 1; // generic heartbeat send
infoJSON["b"] = double(infoPacket.batteryVoltage / 1000.0);
infoJSON["s1"] = infoPacket.numDevicesConnected;
infoJSON["s2"] = infoPacket.waterDetected;
infoJSON["s3"] = infoPacket.mainsPowerConnected;
infoJSON["s4"] = UINT16_MAX;
infoJSON["s5"] = UINT16_MAX;
infoJSON["dt"] = infoPacket.device_type;
char jsonString[256];
serializeJson(infoJSON, jsonString);
PL(jsonString);
cell_cmds(jsonString, infoPacket.node_id);
}
template <> void send_to_cell<Packet>(const Packet dataPacket) {
StaticJsonDocument<300> packetJSON;
packetJSON["r"] = dataPacket.reason;
packetJSON["dt"] = dataPacket.device_type;
packetJSON["eui"] = dataPacket.node_id;
packetJSON["s1"] = dataPacket.sns_reading_1;
packetJSON["s2"] = dataPacket.sns_reading_2;
packetJSON["s3"] = dataPacket.sns_reading_3;
packetJSON["s4"] = dataPacket.sns_reading_4;
packetJSON["s5"] = dataPacket.sns_reading_5;
packetJSON["b"] = double(dataPacket.batt_reading / 1000.0);
packetJSON["snr"] = dataPacket.snr;
packetJSON["rssi"] = dataPacket.rssi;
char jsonString[300];
serializeJson(packetJSON, jsonString);
PL(jsonString);
cell_cmds(jsonString, dataPacket.node_id);
}
// lora rx callback
void recv_cb(rui_lora_p2p_recv_t data) {
memcpy(&newData, data.Buffer, data.BufferSize);
newData.rssi = data.Rssi;
newData.snr = data.Snr;
mainDataBuff.unshift(newData);
}
// check if cellular is connected
bool checkConnection() {
// wait until cell is registered
String command = "AT+CREG?\r";
while (true) {
BG77_write(command.c_str());
String bg_rsp = BG77_read(300);
{
int v = bg_rsp.indexOf('0,');
if (v > 0) {
if (bg_rsp[v + 1] == '5') {
PL("Registered: Roaming");
return true;
} else if (bg_rsp[v + 1] == '1') {
PL("Registered: Home");
return true;
}
}
}
}
}
// setup modem
void configureCell(const char *id) {
// turn verbose errors on
String command = "AT+CMEE=2\r";
BG77_write(command.c_str());
BG77_read(300);
// disable gps
command = "AT+QGPSEND\r";
BG77_write(command.c_str());
BG77_read(300);
// set full functionality of radio
command = "AT+CFUN=1,0\r";
BG77_write(command.c_str());
BG77_read(1000);
// check if sim is ready or needs password
// should return +CPIN: READY
command = "AT+CPIN?\r";
BG77_write(command.c_str());
BG77_read(1000);
command = "AT+COPS=0\r";
BG77_write(command.c_str());
BG77_read(1000);
// set emtc lte mode
command = "AT+QCFG=\"iotopmode\",0,1\r";
BG77_write(command.c_str());
BG77_read(1000);
// check signal strength
command = "AT+CSQ\r";
BG77_write(command.c_str());
BG77_read(1000);
// check sim operator?
command = "AT+COPS?\r";
BG77_write(command.c_str());
BG77_read(1000);
command = "AT+CGATT=1\r";
BG77_write(command.c_str());
BG77_read(1000);
// check connection to service
checkConnection();
// check current network info
command = "AT+QNWINFO\r";
BG77_write(command.c_str());
BG77_read(3000);
// open network for mqtt client
command = "AT+QMTOPEN=0,";
command += SERVER;
command += ",";
command += PORT;
command += "\r";
BG77_write(command.c_str());
BG77_read(30000);
// checking to make sure were good
command = "AT+QMTOPEN?\r";
BG77_write(command.c_str());
BG77_read(30000);
// connect to client
command = "AT+QMTCONN=0,\"";
command += "CMPS";
command += __RAK_NODE_ID_LOWER;
command += "\",";
command += USERNAME;
command += ",\"\"\r"; // password = ""
BG77_write(command.c_str());
BG77_read(30000);
// check if we connected
command = "AT+QMTCONN?\r";
BG77_write(command.c_str());
BG77_read(10000);
}
// if modem off, wake it up
void wakeupCell() {
time_t timeout = millis();
bool moduleSleeps = true;
Serial1.println("ATI");
while ((millis() - timeout) < 6000) {
if (Serial1.available()) {
String result = Serial1.readString();
PL("Modem response after start:");
PL(result);
moduleSleeps = false;
}
}
if (moduleSleeps) {
// Module slept, wake it up
pinMode(BG77_POWER_KEY, OUTPUT);
digitalWrite(BG77_POWER_KEY, 0);
delay(1000);
digitalWrite(BG77_POWER_KEY, 1);
delay(2000);
digitalWrite(BG77_POWER_KEY, 0);
delay(1000);
}
PL("BG77 power up!");
}
void setup() {
CN(115200);
Serial1.begin(115200);
delay(1000);
// setup device info
infoPacket.device_type = Gateway; // 0 = gateway
ID_Builder(infoPacket.node_id);
// TOPIC += infoPacket.node_id;
wakeupCell();
configureCell(infoPacket.node_id);
// setup default settings
if (api.lorawan.nwm.get() != RAK_LORA_P2P) {
PL("Setting device into P2P mode and restarting..");
api.lorawan.nwm.set(RAK_LORA_P2P);
api.system.reboot();
}
PL("Configuring");
api.lorawan.pfreq.set(US_FREQ);
api.lorawan.psf.set(sf);
api.lorawan.pbw.set(bw);
api.lorawan.pcr.set(cr);
api.lorawan.ppl.set(preamble);
api.lorawan.ptp.set(txPower);
cxinfo.RESERVED = 0x0;
cxinfo.sf = sf;
cxinfo.bw = bw;
cxinfo.cr = cr;
cxinfo.txPower = txPower;
// register callbacks
api.lorawan.registerPRecvCallback(recv_cb);
api.lorawan.precv(65533);
// TODO: set pins for water interrupts
// TODO: setup adc
}
void loop() {
if (false) // TODO: commissioning mode again
{ // commissioning mode is active
api.lorawan.psend(sizeof(cxinfo), (uint8_t *)&cxinfo);
delay(10000); // wait 10 seconds inbetween sends
} else {
while (!mainDataBuff.isEmpty()) {
// get node from queue and remove
Packet currData = mainDataBuff.pop();
const char *lastFourChars =
&currData.node_id[strnlen(currData.node_id, 17) - 4];
uniqueDevList[atoi(lastFourChars)] = millis();
// send info over mqtt to ubidots
send_to_cell(currData);
}
if (millis() - curr_tx_timer > TIME_TO_TX || firstBoot) {
// check if any devices have stopped communicating
for (const auto &iterator : uniqueDevList) {
// if not heard from in x minutes, remove from list
if (millis() - iterator.second > 18000) // > 3600000) // one hour
{
uniqueDevList.erase(iterator.first);
}
}
// get info to send
firstBoot = false;
infoPacket.numDevicesConnected = uniqueDevList.size();
// info.batteryVoltage = []
// {
// uint16_t voltage_adc = analogRead(BATT_READ);
// return (uint16_t)((3.3 / 4096) * voltage_adc) * 1000;
// }();
// info.mainsPowerConnected = !digitalRead(PGOOD_LOW);
infoPacket.batteryVoltage = uint16_t(3.3F * 1000); //! set as 3.3V for now
infoPacket.mainsPowerConnected = 1; //! leave as true for now
// send info over mqtt to ubidots
send_to_cell(infoPacket);
infoPacket.waterDetected = 0;
// reset timer
curr_tx_timer = millis();
}
if (millis() - curr_reconn_timer > TIME_TO_RECONN) {
String command = "AT+QMTOPEN=0,";
command += SERVER;
command += ",";
command += PORT;
command += "\r";
BG77_write(command.c_str());
BG77_read(10000);
command = "AT+QMTCONN=0,\"";
command += "CMPS";
command += __RAK_NODE_ID_LOWER;
command += "\",";
command += USERNAME;
command += ",\"\"\r"; // password = ""
BG77_write(command.c_str());
BG77_read(10000);
curr_reconn_timer = millis();
}
}
}
Thank you all for your time!
