Anleitung für einen schnell zusammengebauten Sensor-Knoten mit LoRa-Interface
Hintergrund
Projekt LoRa
Hardware-Stückliste
ESP32 mit LoRa Transceiver, WLAN
Luftgütesensor MQ-135 mit AD-Wandler ADS1115 auf Breadboard
Gesamtaufbau (Der separate AD-Wandler ist nötig, da der AD-Wandler auf dem Board nur maximal 3,3V verträgt.)
Name |
Regierungszeit |
Beschaffung
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Ein auf der ESP32-Architektur basierendes Developer Board mit LoRa-Funkmodul (Detaillierte Vorstellung bei Heise), am besten mit OLED-Display, in Europa sind die Frequenzen um 433MHz oder 868MHz möglich. Unser erster Gateway arbeitet auf 868MHz. |
Preise je nach Quelle zwischen 10 USD und 35 EUR. |
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Sensor - wir wählen hier einen MQ-135, der eine recht allgemeine Aussage zur Luftqualität liefert (Benzol, Alkohol, Rauch, Ammoniak, Sulfide, Aromaten) |
Ab 2 EUR beim Chinesen |
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ADS1115 AD-Wandler mit I2C (eigentlich könnte das Developer-Board AD-Wandeln auch direkt selbst, aber der oben beschriebene Typ verträgt nur 3,3V am Eingang und der MQ-135 liefert zwischen 0 und 5V am Ausgang, je nach Konzentration) |
ca. 10 EUR |
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Optional Breadboard und Kabel für Versuchsaufbau |
ca. 10 EUR |
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Entwicklungsumgebung einrichten
- Arduino IDE. Das hier verwendete Entwicklungs-Board mit ESP32 lässt sich unter anderem mittels Arduino IDE programmieren
- Eventuell braucht das entsprechende Betriebssystem einen Treiber für den auf dem Entwicklungs-Board vorhandenen USB-Serial-Converter
- Arduino Core API für ESP32 installieren
- In der Arduino IDE Treiber fürs Board installieren
Software
- C-Code (Arduino-Style) zum Auslesen des Sensors und Versenden des Ergebnisses per LoRaWAN
#include <Arduino.h>
#include <U8g2lib.h>
//https://github.com/olikraus/u8g2
#include "esp_system.h"
#include <lmic.h>
#include <hal/hal.h>
#include <SPI.h>
#include <Wire.h>
#include <Adafruit_ADS1015.h>
Adafruit_ADS1115 ads; /* Use this for the 16-bit version */
// LoRaWAN NwkSKey, network session key
// This is the default Semtech key, which is used by the prototype TTN
// network initially.
static const PROGMEM u1_t NWKSKEY[16] = { 0x2B, 0x7E, 0x15, 0x16, 0x28, 0xAE, 0xD2, 0xA6, 0xAB, 0xF7, 0x15, 0x88, 0x09, 0xCF, 0x4F, 0x3C };
// LoRaWAN AppSKey, application session key
// This is the default Semtech key, which is used by the prototype TTN
// network initially.
static const u1_t PROGMEM APPSKEY[16] = { 0x2B, 0x7E, 0x15, 0x16, 0x28, 0xAE, 0xD2, 0xA6, 0xAB, 0xF7, 0x15, 0x88, 0x09, 0xCF, 0x4F, 0x3C };
// LoRaWAN end-device address (DevAddr)
// See http://thethingsnetwork.org/wiki/AddressSpace
static const u4_t DEVADDR = 0x03FF0001 ; // <-- Change this address for every node!
int ledPin = 25; // select the pin for the LED
int16_t sensorValue = 0; // variable to store the value coming from the sensor
int counter = 0;
// These callbacks are only used in over-the-air activation, so they are
// left empty here (we cannot leave them out completely unless
// DISABLE_JOIN is set in config.h, otherwise the linker will complain).
void os_getArtEui (u1_t* buf) { }
void os_getDevEui (u1_t* buf) { }
void os_getDevKey (u1_t* buf) { }
uint8_t mydata[] = "Empty";
static osjob_t sendjob;
// Schedule TX every this many seconds (might become longer due to duty
// cycle limitations).
const unsigned TX_INTERVAL = 60;
// Pin mapping
const lmic_pinmap lmic_pins = {
.nss = 6,
.rxtx = LMIC_UNUSED_PIN,
.rst = 5,
.dio = {2, 3, 4},
};
void onEvent (ev_t ev) {
Serial.print(os_getTime());
Serial.print(": ");
switch(ev) {
case EV_SCAN_TIMEOUT:
Serial.println(F("EV_SCAN_TIMEOUT"));
break;
case EV_BEACON_FOUND:
Serial.println(F("EV_BEACON_FOUND"));
break;
case EV_BEACON_MISSED:
Serial.println(F("EV_BEACON_MISSED"));
break;
case EV_BEACON_TRACKED:
Serial.println(F("EV_BEACON_TRACKED"));
break;
case EV_JOINING:
Serial.println(F("EV_JOINING"));
break;
case EV_JOINED:
Serial.println(F("EV_JOINED"));
break;
case EV_RFU1:
Serial.println(F("EV_RFU1"));
break;
case EV_JOIN_FAILED:
Serial.println(F("EV_JOIN_FAILED"));
break;
case EV_REJOIN_FAILED:
Serial.println(F("EV_REJOIN_FAILED"));
break;
break;
case EV_TXCOMPLETE:
Serial.println(F("EV_TXCOMPLETE (includes waiting for RX windows)"));
if(LMIC.dataLen) {
// data received in rx slot after tx
Serial.print(F("Data Received: "));
Serial.write(LMIC.frame+LMIC.dataBeg, LMIC.dataLen);
Serial.println();
}
// Schedule next transmission
os_setTimedCallback(&sendjob, os_getTime()+sec2osticks(TX_INTERVAL), do_send);
break;
case EV_LOST_TSYNC:
Serial.println(F("EV_LOST_TSYNC"));
break;
case EV_RESET:
Serial.println(F("EV_RESET"));
break;
case EV_RXCOMPLETE:
// data received in ping slot
Serial.println(F("EV_RXCOMPLETE"));
break;
case EV_LINK_DEAD:
Serial.println(F("EV_LINK_DEAD"));
break;
case EV_LINK_ALIVE:
Serial.println(F("EV_LINK_ALIVE"));
break;
default:
Serial.println(F("Unknown event"));
break;
}
}
void do_send(osjob_t* j){
// Check if there is not a current TX/RX job running
if (LMIC.opmode & OP_TXRXPEND) {
Serial.println(F("OP_TXRXPEND, not sending"));
} else {
// Prepare upstream data transmission at the next possible time.
LMIC_setTxData2(1, mydata, sizeof(mydata)-1, 0);
Serial.println(F("Packet queued"));
}
// Next TX is scheduled after TX_COMPLETE event.
}
// U8g2 Contructor List (Frame Buffer)
// The complete list is available here: https://github.com/olikraus/u8g2/wiki/u8g2setupcpp
U8G2_SSD1306_128X64_NONAME_F_SW_I2C u8g2(U8G2_R0, /* clock=*/ 15, /* data=*/ 4, /* reset=*/ 16);
#define opennetlogobw_width 64
#define opennetlogobw_height 64
static unsigned char opennetlogobw_bits[] = {
0x00, 0x00, 0x80, 0xff, 0x1f, 0x00, 0x00, 0x00, 0x00, 0x00, 0xf8, 0x07,
0xfc, 0x03, 0x00, 0x00, 0x00, 0x00, 0x0f, 0x00, 0x00, 0x1f, 0x00, 0x00,
0x00, 0xe0, 0x01, 0x00, 0x00, 0x78, 0x00, 0x00, 0x00, 0x38, 0x00, 0x00,
0x00, 0xc0, 0x03, 0x00, 0x00, 0x0e, 0x00, 0x00, 0x00, 0x00, 0x07, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x1c, 0x00, 0x00, 0x00, 0xc0, 0xff,
0x3f, 0x00, 0x70, 0x00, 0x00, 0x00, 0xf8, 0x00, 0xf0, 0x03, 0xc0, 0x00,
0x00, 0x00, 0x0f, 0x00, 0x00, 0x0f, 0x80, 0x01, 0x00, 0xc0, 0x01, 0x00,
0x00, 0x38, 0x00, 0x03, 0x00, 0x40, 0x00, 0x00, 0x00, 0xe0, 0x00, 0x06,
0x00, 0x00, 0x00, 0x00, 0x00, 0x80, 0x03, 0x1c, 0x00, 0x00, 0x00, 0xfc,
0x03, 0x00, 0x06, 0x38, 0x00, 0x00, 0xc0, 0xff, 0x7f, 0x00, 0x1c, 0x30,
0x00, 0x00, 0x78, 0x00, 0xe0, 0x01, 0x38, 0x60, 0x00, 0x00, 0x0e, 0x00,
0x00, 0x07, 0x60, 0xc0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x1c, 0xc0, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x30, 0x80, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0xe0, 0x80, 0x01, 0x00, 0x00, 0x00, 0xfe, 0x07, 0x80, 0x01, 0x01,
0x00, 0x00, 0xc0, 0x07, 0x3c, 0x00, 0x03, 0x00, 0x00, 0x00, 0x60, 0x00,
0xe0, 0x00, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x80, 0x01, 0x06, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x07, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x0c, 0x00, 0x00, 0x00, 0x00, 0x00, 0xe0, 0x00, 0x18, 0x00, 0x00,
0x00, 0x00, 0x00, 0xfe, 0x07, 0x08, 0x00, 0x00, 0x00, 0x00, 0x00, 0x06,
0x1c, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x38, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x60, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x78, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0xfe, 0x01, 0x80, 0x1f, 0x00, 0x00, 0x00, 0x00, 0xff, 0x03,
0xc0, 0x3f, 0x00, 0x00, 0x00, 0x00, 0xff, 0x07, 0xe0, 0x7f, 0x00, 0x00,
0x00, 0x00, 0xff, 0x07, 0xe0, 0x7f, 0x00, 0x00, 0x00, 0x02, 0xff, 0x07,
0xe0, 0xff, 0x00, 0x00, 0x00, 0x04, 0xfe, 0x03, 0xe0, 0x7f, 0x00, 0x00,
0x00, 0x0c, 0xfc, 0x03, 0xe0, 0x7f, 0x00, 0x00, 0x00, 0x38, 0xf0, 0x00,
0xc0, 0x3f, 0x80, 0x00, 0x00, 0x78, 0x00, 0x00, 0x00, 0x06, 0xc0, 0x00,
0x00, 0xf0, 0x01, 0x00, 0x01, 0x00, 0x60, 0x00, 0x00, 0xf0, 0x07, 0x10,
0x1e, 0x00, 0x78, 0x00, 0x00, 0xe0, 0x3f, 0x0f, 0xf8, 0x07, 0x7e, 0x00,
0x00, 0xe0, 0xff, 0x07, 0xf0, 0xff, 0x7f, 0x00, 0x00, 0xe0, 0xff, 0x07,
0xc0, 0xff, 0x7f, 0x00, 0x00, 0xe0, 0xff, 0x03, 0x80, 0xff, 0x3f, 0x00,
0x00, 0xe0, 0xff, 0x01, 0x00, 0xff, 0x3f, 0x00, 0x00, 0xf0, 0xff, 0x01,
0x00, 0xfe, 0x3f, 0x00, 0x00, 0xf8, 0xff, 0x00, 0x00, 0xfe, 0x3f, 0x00,
0x00, 0xfe, 0xff, 0x00, 0x00, 0xfc, 0x7f, 0x00, 0x80, 0xff, 0xff, 0x00,
0x00, 0xfc, 0x7f, 0x00, 0xe0, 0x03, 0xff, 0x00, 0x00, 0xfe, 0xff, 0x00,
0x04, 0x00, 0xf8, 0x00, 0x00, 0xfe, 0xff, 0x00, 0x00, 0x00, 0xf0, 0x00,
0x00, 0xff, 0xff, 0x01, 0x00, 0x00, 0xe0, 0x00, 0x00, 0x3f, 0xe0, 0x01,
0x00, 0x00, 0xc0, 0x00, 0x80, 0x0f, 0x80, 0x03, 0x00, 0x00, 0x80, 0x00,
0xc0, 0x03, 0x00, 0x06, 0x00, 0x00, 0x80, 0x00, 0xe0, 0x00, 0x00, 0x08,
0x00, 0x00, 0x00, 0x01, 0x30, 0x00, 0x00, 0x10, 0x00, 0x00, 0x00, 0x00,
0x08, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x04, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
void u8g2_bitmap_modes(uint8_t transparent) {
const uint8_t frame_size = 24;
u8g2.setDrawColor(1);// Black
u8g2.drawXBMP(0, 0, opennetlogobw_width, opennetlogobw_height, opennetlogobw_bits);
}
void setup(void) {
ads.begin();
u8g2.begin();
u8g2.setFont(u8g2_font_6x10_tf);
//https://github.com/olikraus/u8g2/wiki/fntgrpx11
u8g2.setFontRefHeightExtendedText();
u8g2.setDrawColor(1);
u8g2.setFontPosTop();
u8g2.setFontDirection(0);
pinMode(ledPin, OUTPUT);
Serial.begin(115200);
Serial.println("Programm gestartet!");
// // LMIC init
// os_init();
// // Reset the MAC state. Session and pending data transfers will be discarded.
// LMIC_reset();
// // Set static session parameters. Instead of dynamically establishing a session
// // by joining the network, precomputed session parameters are be provided.
// #ifdef PROGMEM
// // On AVR, these values are stored in flash and only copied to RAM
// // once. Copy them to a temporary buffer here, LMIC_setSession will
// // copy them into a buffer of its own again.
// uint8_t appskey[sizeof(APPSKEY)];
// uint8_t nwkskey[sizeof(NWKSKEY)];
// memcpy_P(appskey, APPSKEY, sizeof(APPSKEY));
// memcpy_P(nwkskey, NWKSKEY, sizeof(NWKSKEY));
// LMIC_setSession (0x1, DEVADDR, nwkskey, appskey);
// #else
// // If not running an AVR with PROGMEM, just use the arrays directly
// LMIC_setSession (0x1, DEVADDR, NWKSKEY, APPSKEY);
// #endif
// // Set up the channels used by the Things Network, which corresponds
// // to the defaults of most gateways. Without this, only three base
// // channels from the LoRaWAN specification are used, which certainly
// // works, so it is good for debugging, but can overload those
// // frequencies, so be sure to configure the full frequency range of
// // your network here (unless your network autoconfigures them).
// // Setting up channels should happen after LMIC_setSession, as that
// // configures the minimal channel set.
// LMIC_setupChannel(0, 868100000, DR_RANGE_MAP(DR_SF12, DR_SF7), BAND_CENTI); // g-band
// LMIC_setupChannel(1, 868300000, DR_RANGE_MAP(DR_SF12, DR_SF7B), BAND_CENTI); // g-band
// LMIC_setupChannel(2, 868500000, DR_RANGE_MAP(DR_SF12, DR_SF7), BAND_CENTI); // g-band
// LMIC_setupChannel(3, 867100000, DR_RANGE_MAP(DR_SF12, DR_SF7), BAND_CENTI); // g-band
// LMIC_setupChannel(4, 867300000, DR_RANGE_MAP(DR_SF12, DR_SF7), BAND_CENTI); // g-band
// LMIC_setupChannel(5, 867500000, DR_RANGE_MAP(DR_SF12, DR_SF7), BAND_CENTI); // g-band
// LMIC_setupChannel(6, 867700000, DR_RANGE_MAP(DR_SF12, DR_SF7), BAND_CENTI); // g-band
// LMIC_setupChannel(7, 867900000, DR_RANGE_MAP(DR_SF12, DR_SF7), BAND_CENTI); // g-band
// LMIC_setupChannel(8, 868800000, DR_RANGE_MAP(DR_FSK, DR_FSK), BAND_MILLI); // g2-band
// // TTN defines an additional channel at 869.525Mhz using SF9 for class B
// // devices' ping slots. LMIC does not have an easy way to define set this
// // frequency and support for class B is spotty and untested, so this
// // frequency is not configured here.
// Disable link check validation
// LMIC_setLinkCheckMode(0);
// // Set data rate and transmit power (note: txpow seems to be ignored by the library)
// LMIC_setDrTxpow(DR_SF7,14);
// // Start job
// do_send(&sendjob);
}
void loop(void) {
digitalWrite(ledPin, LOW);
u8g2.clearBuffer();
u8g2_bitmap_modes(0);
int16_t sensorValue;
sensorValue = ads.readADC_SingleEnded(0);
u8g2.setFont(u8g2_font_6x10_tf);
char c[64];
String str;
str = String(sensorValue);
Serial.println(str);
str.getBytes(mydata, 64);
// mydata will be sent in do_send() which is also called in case we receive a EV_TXCOMPLETE event
str.toCharArray(c, 64);
u8g2.drawStr(75,0, "Sensor");
u8g2.drawStr(75,10, "readout:");
u8g2.drawStr(75,20, c);
u8g2.drawStr(75,34, "LoRaWAN");
u8g2.drawStr(75,44, "message");
str = String(counter);
Serial.println(str);
str.toCharArray(c, 64);
u8g2.drawStr(75,54, c);
counter++;
u8g2.sendBuffer();
delay(2500);
digitalWrite(ledPin, HIGH);
delay(2500);
}
- InfluxDB und Grafana
Verlauf der Sensor-Messwerte vom MQ-135