TTGO T-Beam topic

Hi

Does anyone have a example sketch to connect a ttgo T-beam to The Things Network?

Thanks

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Look here, T-Beam is supported:

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Thanks!!

I ported a simple TTN Mapper sketch to the T-Beam, might be good for starters.

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I just tried using the deep sleep mode and the TTGO t-beam board still draws 44mA.
The product description says:
Sleep current :0.2uA@SLEEP
1.5uA@IDLE

I know the TTGO Lora had issues with deep sleep too. I was just hoping that this one was better.

2 questions

  • What is the minimum current achievable with the TTGO lora just by code and without changing the board physically? Code example would be great too.
  • Can you disable peripherals just by code. I am not familiar with that. Is that just by redefining pins to low or input?

Has anyone taken advantage of onboard PSRAM ?

Wi-Fi and BT (Classis & LE) are very RAM hungry functionalities - it seems that very soon the ESP-IDF and app(s) will exhaust all the ESP32’s built-in memory available…

That’s strange. Yesterday I tried to measure its current consumption - on USB power - and tis was drawing around 10 mA only - not even sleeping.

Edit : forget that, bad reading on my part : it’s actually 50 to 80 mA on the USB 5V.

Yes, PSRAM is automatically present since using the new arduino-espressif32 core v1.1.0; i now get 4 MB free RAM.

oooh nice, time to update, thanks for the heads-up.

Be careful when updating. I ran in several issues i had to solve after update.
And one issue is getting I2C timeout errors, which i could not fix yet.

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No problems on my side, was not using I²C anyway.

My total “dynamic memory” only changed from 294912 to 327680 bytes then. Did you do anything special to get that 4MB figure ?

Maybe we compare different values here.
My 4MB RAM are shown by ESP.getFreeHeap():

[D][esp32-hal-psram.c:48] psramInit(): PSRAM enabled
[I][main.cpp:490] setup(): Starting PAXCNT 1.3.83
[I][main.cpp:507] setup(): This is ESP32 chip with 2 CPU cores, WiFi/BT/BLE, silicon revision 1, 4MB external Flash
[I][main.cpp:508] setup(): ESP32 SDK: v3.2-dev-39-gaaf12390
...
[D][macsniff.cpp:83] mac_add(): new   WiFi RSSI -93dBi -> MAC 25CAD083 -> Hash 5A14 -> WiFi:1  BLTH:0 -> **4245260 Bytes left**

Hello everyone,
I’m interested in getting a T-Beam and I’d like to know if there are any hardware issues with it. Does low power work for all modules on board?

There are no special low power features on T-Beam, i.e. it is not possible to deactivate the USB driver and the battery charging circuit. For low power you should select other device, i.e. Nexus by Ideetron.

Does LoRa32 v2.1 have these issues fixed? I could add a gps module to that board.

No. As far as i see all TTGO boards are based on the same common schematics.
Again, if you’re looking for low power devices, you’re looking for something more elaborated, and again, i would recommend www.ideetron.nl

You may also go for a SODAQ.

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Ok, thank you! I’ll look into them.

hello,
i was triyng to program the ttgo t-beam butt i get this error:

LMIC_setSession (0x1, DEVADDR, NWKSKEY, APPSKEY);

exit status 1
‘DEVADDR’ was not declared in this scope

Can you share your code ? But please use proper formatting as described HERE

Here is my code:

#include <TinyGPS++.h>
#include <lmic.h>
#include <hal/hal.h>
#include <WiFi.h>

// UPDATE the config.h file in the same folder WITH YOUR TTN KEYS AND ADDR.
#include "config.h"

// T-Beam specific hardware
#define BUILTIN_LED 21
#define GPS_TX 12
#define GPS_RX 15

// The TinyGPS++ object
TinyGPSPlus gps;
HardwareSerial GPSSerial(1);

char s[32]; // used to sprintf for Serial output

// 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) { }

static osjob_t sendjob;
// Schedule TX every this many seconds (might become longer due to duty cycle limitations).
const unsigned TX_INTERVAL = 30;

// Pin mapping
const lmic_pinmap lmic_pins = {
  .nss = 18,
  .rxtx = LMIC_UNUSED_PIN,
  .rst = LMIC_UNUSED_PIN, // was "14,"
  .dio = {26, 33, 32},
};

unsigned long last_update = 0;
String toLog;
uint8_t txBuffer[9];
uint32_t LatitudeBinary, LongitudeBinary;
uint16_t altitudeGps;
uint8_t hdopGps;

#define PMTK_SET_NMEA_UPDATE_05HZ  "$PMTK220,2000*1C"
#define PMTK_SET_NMEA_UPDATE_1HZ  "$PMTK220,1000*1F"
#define PMTK_SET_NMEA_OUTPUT_RMCGGA "$PMTK314,0,1,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0*28"

void build_packet()
{
  while (GPSSerial.available())
  {
    gps.encode(GPSSerial.read());
  }
  LatitudeBinary = ((gps.location.lat() + 90) / 180.0) * 16777215;
  LongitudeBinary = ((gps.location.lng() + 180) / 360.0) * 16777215;
  
  sprintf(s, "Lat: %f", gps.location.lat());
  Serial.println(s);
  
  sprintf(s, "Lng: %f", gps.location.lng());
  Serial.println(s);
  
  txBuffer[0] = ( LatitudeBinary >> 16 ) & 0xFF;
  txBuffer[1] = ( LatitudeBinary >> 8 ) & 0xFF;
  txBuffer[2] = LatitudeBinary & 0xFF;

  txBuffer[3] = ( LongitudeBinary >> 16 ) & 0xFF;
  txBuffer[4] = ( LongitudeBinary >> 8 ) & 0xFF;
  txBuffer[5] = LongitudeBinary & 0xFF;

  altitudeGps = gps.altitude.meters();
  txBuffer[6] = ( altitudeGps >> 8 ) & 0xFF;
  txBuffer[7] = altitudeGps & 0xFF;

  hdopGps = gps.hdop.value()/10;
  txBuffer[8] = hdopGps & 0xFF;

  toLog = "";
  for(size_t i = 0; i<sizeof(txBuffer); i++)
  {
    char buffer[3];
    sprintf(buffer, "%02x", txBuffer[i]);
    toLog = toLog + String(buffer);
  }
  Serial.println(toLog);
}

void onEvent (ev_t ev) {
  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"));
      // Disable link check validation (automatically enabled
      // during join, but not supported by TTN at this time).
      LMIC_setLinkCheckMode(0);
      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;
    case EV_TXCOMPLETE:
      Serial.println(F("EV_TXCOMPLETE (includes waiting for RX windows)"));
      digitalWrite(BUILTIN_LED, LOW);
      if (LMIC.txrxFlags & TXRX_ACK) {
        Serial.println(F("Received Ack"));
      }
      if (LMIC.dataLen) {
        sprintf(s, "Received %i bytes of payload", LMIC.dataLen);
        Serial.println(s);
        sprintf(s, "RSSI %d SNR %.1d", LMIC.rssi, LMIC.snr);
        Serial.println(s);
      }
      // 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.
    build_packet();
    LMIC_setTxData2(1, txBuffer, sizeof(txBuffer), 0);
    Serial.println(F("Packet queued"));
    digitalWrite(BUILTIN_LED, HIGH);
  }
  // Next TX is scheduled after TX_COMPLETE event.
}

void setup() {
  Serial.begin(115200);
  Serial.println(F("TTN Mapper"));
  
  //Turn off WiFi and Bluetooth
  WiFi.mode(WIFI_OFF);
  btStop();
  
  GPSSerial.begin(9600, SERIAL_8N1, GPS_TX, GPS_RX);
  GPSSerial.setTimeout(2);

  GPSSerial.println(F(PMTK_SET_NMEA_OUTPUT_RMCGGA));
  GPSSerial.println(F(PMTK_SET_NMEA_UPDATE_1HZ));   // 1 Hz update rate
  
  // LMIC init
  os_init();
  // Reset the MAC state. Session and pending data transfers will be discarded.
  LMIC_reset();
  
 
  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

  // Disable link check validation
  LMIC_setLinkCheckMode(0);

  // TTN uses SF9 for its RX2 window.
  LMIC.dn2Dr = DR_SF9;

  // Set data rate and transmit power for uplink (note: txpow seems to be ignored by the library)
  LMIC_setDrTxpow(DR_SF7,14); 
  
  // Start job 
  do_send(&sendjob);
  pinMode(BUILTIN_LED, OUTPUT);
  digitalWrite(BUILTIN_LED, LOW);
}

void loop() {
  os_runloop_once();
}
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