feature/lora: Enable LoraWAN supported hardware

* Allows OpenEVSE units (with a LoraWAN compatible modem)
  to announce their status up to several miles to TheThingsNetwork
  or Helium IoT gateways.
* Must be using a ESP32 with a built-in LoRA modem, or by
  manually attaching a LoRA modem to a stock ESP32

Author: kallisti5

platformio.ini

@@ -87,6 +87,8 @@ build_flags =
   -D AO_DBG_LEVEL=AO_DL_INFO
   -D AO_MG_VERSION_614 ; use MG v6.14
   -D AO_CA_CERT_LOCAL ; manage certificate locally
+  -D ARDUINO_LMIC_PROJECT_CONFIG_H_SUPPRESS
+  -D hal_init=LMICHAL_init ; Workaround mcci arduino-lmic bug 714 on esp32
   #-D ENABLE_DEBUG
   #-D ENABLE_DEBUG_MONGOOSE_HTTP_CLIENT
   -D RAPI_MAX_COMMANDS=20
@@ -316,6 +318,10 @@ upload_speed = 921600
 
 [env:openevse_esp32-heltec-wifi-lora-v2]
 board = heltec_wifi_lora_32_V2
+lib_deps =
+  ${common.lib_deps}
+  MCCI LoRaWAN LMIC library
+# https://github.com/mcci-catena/arduino-lmic#selecting-the-lorawan-region-configuration
 build_flags =
   ${common.build_flags}
   ${common.src_build_flags}
@@ -328,3 +334,11 @@ build_flags =
   -D RAPI_PORT=Serial1
   -D RX1=25
   -D TX1=27
+  -D CFG_us915        ; USA 915Mhz
+  -D CFG_sx1276_radio ; SX1275 radio
+  -D ENABLE_LORA=1
+  -D LORA_NSS=18
+  -D LORA_RST=14
+  -D LORA_DIO0=26
+  -D LORA_DIO1=35
+  -D LORA_DIO2=34

src/app_config.cpp

@@ -62,6 +62,11 @@ String mqtt_vehicle_range;
 String mqtt_vehicle_eta;
 String mqtt_announce_topic;
 
+// LoraWAN network settings
+String lora_deveui;
+String lora_appeui;
+String lora_appkey;
+
 // OCPP 1.6 Settings
 String ocpp_server;
 String ocpp_chargeBoxId;

src/app_config.h

@@ -49,6 +49,11 @@ extern String mqtt_vehicle_range;
 extern String mqtt_vehicle_eta;
 extern String mqtt_announce_topic;
 
+// LoraWAN Settings
+extern String lora_deveui;
+extern String lora_appeui;
+extern String lora_appkey;
+
 // OCPP 1.6 Settings
 extern String ocpp_server;
 extern String ocpp_chargeBoxId;
@@ -97,6 +102,7 @@ extern uint32_t flags;
 #define CONFIG_OCPP_AUTO_AUTH       (1 << 22)
 #define CONFIG_OCPP_OFFLINE_AUTH    (1 << 23)
 #define CONFIG_THREEPHASE           (1 << 24)
+#define CONFIG_SERVICE_LORA         (1 << 25)
 
 
 inline bool config_emoncms_enabled() {
@@ -127,6 +133,10 @@ inline bool config_mqtt_reject_unauthorized() {
   return 0 == (flags & CONFIG_MQTT_ALLOW_ANY_CERT);
 }
 
+inline bool config_lora_enabled() {
+  return CONFIG_SERVICE_LORA == (flags & CONFIG_SERVICE_LORA);
+}
+
 inline bool config_ocpp_enabled() {
   return CONFIG_SERVICE_OCPP == (flags & CONFIG_SERVICE_OCPP);
 }

src/input.cpp

@@ -155,6 +155,29 @@ void create_rapi_json(JsonDocument &doc)
   doc["elapsed"] = evse.getSessionElapsed();
 }
 
+/// A small packed report of unit's status
+void create_rapi_packed(uint8_t *data)
+{
+  if (sizeof(data[0]) / sizeof(data) != 8) {
+    DBUGF("create_rapi_packed: Incorrect data size passed!");
+    return;
+  }
+  // Values with potential > 255 are reduced via a
+  // conversion factor.
+  data[0] = evse.getEvseState();
+  data[1] = evse.getVoltage() / 2;      // CF * 2
+  data[2] = evse.getAmps();
+  data[3] = evse.getChargeCurrent();
+  data[4] = evse.getSessionElapsed() / 60;  // CF * 60
+
+  if(evse.isTemperatureValid(EVSE_MONITOR_TEMP_MONITOR))
+    data[5] = evse.getTemperature(EVSE_MONITOR_TEMP_MONITOR) * TEMP_SCALE_FACTOR;
+  if(evse.isTemperatureValid(EVSE_MONITOR_TEMP_MAX))
+    data[6] = evse.getTemperature(EVSE_MONITOR_TEMP_MAX) * TEMP_SCALE_FACTOR;
+
+  // data[7] what?
+}
+
 void
 handleRapiRead()
 {

src/input.h

@@ -17,6 +17,7 @@ extern String ohm_hour;
 
 extern void handleRapiRead();
 extern void create_rapi_json(JsonDocument &data);
+extern void create_rapi_packed(uint8_t* data);
 
 extern void input_setup();
 

src/lora.cpp

@@ -0,0 +1,152 @@
+/*
+ * Copyright (c) 2019-2020 Alexander von Gluck IV for OpenEVSE
+ *
+ * -------------------------------------------------------------------
+ *
+ * Additional Adaptation of OpenEVSE ESP Wifi
+ * by Trystan Lea, Glyn Hudson, OpenEnergyMonitor
+ * All adaptation GNU General Public License as below.
+ *
+ * -------------------------------------------------------------------
+ *
+ * This file is part of Open EVSE.
+ * Open EVSE is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3, or (at your option)
+ * any later version.
+ * Open EVSE is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * You should have received a copy of the GNU General Public License
+ * along with Open EVSE; see the file COPYING.  If not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+#ifdef ENABLE_LORA
+
+#include <lmic.h>
+#include <hal/hal.h>
+#include <SPI.h>
+
+#include "emonesp.h"
+#include "lora.h"
+
+#include "app_config.h"
+
+
+#define LORA_HTOI(c) ((c<='9')?(c-'0'):((c<='F')?(c-'A'+10):((c<='f')?(c-'a'+10):(0))))
+#define LORA_TWO_HTOI(h, l) ((LORA_HTOI(h) << 4) + LORA_HTOI(l))
+#define LORA_HEX_TO_BYTE(a, h, n) { for (int i = 0; i < n; i++) (a)[i] = LORA_TWO_HTOI(h[2*i], h[2*i + 1]); }
+#define LORA_DEVADDR(a) (uint32_t) ((uint32_t) (a)[3] | (uint32_t) (a)[2] << 8 | (uint32_t) (a)[1] << 16 | (uint32_t) (a)[0] << 24)
+
+#define ANNOUNCE_INTERVAL 30 * 1000 // (In Milliseconds)
+
+
+// TODO: Store these via WebUI? We're doing (simple) ABP activation for now
+//const char *devAddr = "00000000";
+//const char *nwkSKey = "00000000000000000000000000000000";
+//const char *appSKey = "00000000000000000000000000000000";
+
+
+// LoRaWAN credentials to use
+static uint8_t DEVADDR[4];
+static uint8_t NWKSKEY[16];
+static uint8_t APPSKEY[16];
+
+// Next LoRaWAN announcement
+unsigned long nextAnnounce;
+
+// LoRa module pin mapping
+const lmic_pinmap lmic_pins = {
+  .nss = LORA_NSS,
+  .rxtx = LMIC_UNUSED_PIN,
+  .rst = LORA_RST,
+  .dio = {LORA_DIO0, LORA_DIO1, LORA_DIO2},
+};
+
+// Used for OTAA, not used (yet)
+void os_getArtEui (u1_t* buf) { }
+void os_getDevEui (u1_t* buf) { }
+void os_getDevKey (u1_t* buf) { }
+
+
+void onEvent(ev_t ev) {
+  switch (ev) {
+    case EV_TXCOMPLETE:
+      DBUGF("LoRa: TX Complete.");
+      // LoRaWAN transmission complete
+      if (LMIC.txrxFlags & TXRX_ACK) {
+        // Received ack
+        DBUGF("LoRa: TX ack.");
+      }
+      break;
+    case EV_TXSTART:
+      DBUGF("LoRa: TX Begin.");
+      break;
+    default:
+      // Ignore anything else for now
+      break;
+  }
+}
+
+/// Reset LoRa modem. Reload LoRaWAN keys
+void lora_reset()
+{
+  LORA_HEX_TO_BYTE(DEVADDR, lora_deveui.c_str(), 4);
+  LORA_HEX_TO_BYTE(NWKSKEY, lora_appeui.c_str(), 16);
+  LORA_HEX_TO_BYTE(APPSKEY, lora_appkey.c_str(), 16);
+
+  LMIC_reset();
+  LMIC_setSession (0x13, LORA_DEVADDR(DEVADDR), NWKSKEY, APPSKEY);
+  LMIC_setAdrMode(0);
+  LMIC_setClockError(MAX_CLOCK_ERROR * 10 / 100);
+  LMIC_selectSubBand(1);
+  LMIC_setLinkCheckMode(0);
+  LMIC.dn2Dr = DR_SF7;
+}
+
+/// Initial setup of LoRa modem.
+void lora_setup()
+{
+  Profile_Start(lora_setup);
+
+  os_init();
+  lora_reset();
+
+  // Set us up for an immeadiate announcement
+  nextAnnounce = millis();
+ 
+  Profile_End(lora_setup, 1);
+}
+
+/// Announce our status to LoraWAN if it's time
+void lora_publish(uint8_t *dataPacket)
+{
+  if (millis() < nextAnnounce)
+    return;
+
+  Profile_Start(lora_loop);
+  DBUGF("LoRa: Starting LoRaWAN broadcast...");
+  // Check if there is not a current TX/RX job running
+  if (LMIC.opmode & OP_TXRXPEND) {
+    DBUGF("LoRa: Modem busy. Retry later");
+    return;
+  } 
+
+  LMIC_setTxData2(1, dataPacket, sizeof(dataPacket), true);
+  nextAnnounce = millis() + ANNOUNCE_INTERVAL;
+
+  Profile_End(lora_loop, 1);
+}
+
+#else /* !ENABLE_LORA */
+
+#include "emonesp.h"
+#include "app_config.h"
+
+void lora_setup() { /*NOP*/ }
+void lora_reset() { /*NOP*/ }
+void lora_publish(uint8_t *dataPacket) { /*NOP*/ }
+
+#endif

src/lora.h

@@ -0,0 +1,10 @@
+#ifndef _LORA_H
+#define _LORA_H
+
+
+void lora_setup();
+void lora_reset();
+void lora_publish(uint8_t *dataPacket);
+
+
+#endif // _LORA_H

src/main.cpp

@@ -42,6 +42,7 @@
 #include "divert.h"
 #include "ota.h"
 #include "lcd.h"
+#include "lora.h"
 #include "openevse.h"
 #include "root_ca.h"
 #include "espal.h"
@@ -139,6 +140,12 @@ void setup()
   net_setup();
   DBUGF("After net_setup: %d", ESPAL.getFreeHeap());
 
+#ifdef ENABLE_LORA
+  // initialise LoRA if supported
+  lora_setup();
+  DBUGF("After lora_setup: %d" ESPAL.getFreeHeap());
+#endif
+
   // Initialise Mongoose networking library
   Mongoose.begin();
   Mongoose.setRootCa(root_ca);
@@ -248,6 +255,12 @@ loop() {
     }
   } // end WiFi connected
 
+#ifdef ENABLE_LORA
+  uint8_t loraPacket[8];
+  create_rapi_packed(loraPacket);
+  lora_publish(loraPacket);
+#endif
+
   if(DEBUG_PORT.available()) {
     handle_serial();
   }
@@ -335,4 +348,4 @@ void handle_serial()
       DEBUG_PORT.printf("{\"code\":200,\"msg\":\"%s\"}\n", config_modified ? "done" : "no change");
     }
   }
-}
+}