TTGO T-Beam topic

rem73 · February 1, 2019, 12:07pm

“buying a new one is probably cheaper…” : No!! You don"t undestand.
I’m pratically sure that the mistake is not on MY board but on ALL TTGO V1 at 868Mhz:
There is a mystake in the layout: use of PAboost with wrong parts. Or it is only a BOM mistake
Understanding PA SX1276 is not obvious: many frequencies and BOM changes, many power configuration, 2 différents layout available, use or not EMI filter…not so easy as connecting an Oled Display.

Any way , if you are not able to do the measurement with specific hardware, you can not see the difference. 10dB Could be over-pass by good or bad cable and antenna. You will see it only for test at the limit range, with same antenna…

BoRRoZ · February 1, 2019, 12:13pm

ok, therefore you can’t say that changing a few components will help if there is a fundamental design error.

rem73 · February 1, 2019, 12:21pm

To be clear : If you change theses components ( not easy ) and modify LMIC lib, you can improve de transmitted power, to be close to the semtech specification and RFM95

UdLoRa · February 1, 2019, 2:08pm

There is a video by Andreas Spiess about the ESP32 issues due to bad RF design . However, I agree that is likely better to buy an ESP32 alone + RFM95w instead.

BoRRoZ · February 1, 2019, 2:11pm

tnx… Andreas was spotted at The Conference yesterday !

ori · March 18, 2019, 10:44am

I wonder what is this UFL connector for, does anyone know? UFL

EricVdB · March 18, 2019, 10:55am

Wifi ?

bluejedi · March 18, 2019, 10:57am

It is meant for connecting an external Wifi/BT antenna but that would require moving (de/re-soldering) a 0 ohm resistor (on the left of the U.FL connector) from one location to another to switch the RF connection.

ori · March 18, 2019, 11:20am

Not good for the Lora antenna then…

bluejedi · March 18, 2019, 11:24am

That is unrelated to the LoRa antenna (or at least as much related as the on-board Wifi/BT antenna).

ori · March 18, 2019, 11:47am

Any luck/update with regards to the GPS and sleep mode?

Bercman · March 27, 2019, 9:07am

Hello!

I’m new to the LoRaWAN and TTN community.

I’ve been trying to get my TTGO T-Beam to work (connect to TTN) for several days now, but have had no success whatsoever.

What I’ve tried so far:

Downloaded LMIC library and tried out the following pinout settings according to the best TTGO T-Beam pinout information I’ve found so far (incl. soldering LoRa1 to pin 33 and LoRa2 to pin 32 on the board itself):

const lmic_pinmap lmic_pins = {
.nss = 18, // LoRa chip select on ttgo t-beam
.rxtx = LMIC_UNUSED_PIN,
.rst = LMIC_UNUSED_PIN, // Not required
.dio = {26, 33, 32}, // To LoRa DIO0 (interrupt), To LoRa DIO1 (interrupt) & To LoRa DIO2 (interrupt)
};

Updated SPI settings in hal.cpp according to the correct SPI pinout:

static void hal_spi_init () {
// SPI.begin();
SPI.begin(5,19,27); // These specific pins are for TTGO T-Beam only!
}

Tested LMIC AGP example, paying very close attention to little- and big-endian formats. This is what I see (no joining feedback, the last lines just repeat after every 60 seconds as defined):
Baud rate 115200

ets Jun 8 2016 00:22:57

rst:0x1 (POWERON_RESET),boot:0x33 (SPI_FAST_FLASH_BOOT)
configsip: 0, SPIWP:0xee
clk_drv:0x00,q_drv:0x00,d_drv:0x00,cs0_drv:0x00,hd_drv:0x00,wp_drv:0x00
mode:DIO, clock div:1
load:0x3fff0018,len:4
load:0x3fff001c,len:928
ho 0 tail 12 room 4
load:0x40078000,len:9280
load:0x40080400,len:5848
entry 0x40080698
Starting
11124: EV_TXSTART
Packet queued
206222: EV_TXCOMPLETE (includes waiting for RX windows)

Tested LMIC OTAA example, paying very close attention to little- and big-endian formats. This is what I see:
Baud rate 9600 (the last lines just repeat)

⸮as⸮⸮J&&⸮SY
Packet queued
4918: EV_JOINING
4937: EV_TXSTART
414734: EV_TXSTART
843576: EV_TXSTART
1302692: EV_TXSTART
2665242: EV_TXSTART

OTAA example. Baud rate 115200

ets Jun 8 2016 00:22:57
rst:0x1 (POWERON_RESET),boot:0x33 (SPI_FAST_FLASH_BOOT)
configsip: 0, SPIWP:0xee
clk_drv:0x00,q_drv:0x00,d_drv:0x00,cs0_drv:0x00,hd_drv:0x00,wp_drv:0x00
mode:DIO, clock div:1
load:0x3fff0018,len:4
load:0x3fff001c,len:928
ho 0 tail 12 room 4
load:0x40078000,len:9280
load:0x40080400,len:5848
entry 0x40080698

Peeled off the LoRa module sticker to make sure I do not have the 433 MHz LoRa module as I did have with other LoRa modules I failed with as I live in Europe. Although it is not the 433 MHz module, I found HPD13A-915 written on top of the module. Knowing that the TTGO T-Beam advertises itself to be compatible with 868 MHz and 915 MHz at the same time (?!), might this prove to be a problem? I do have to admit I’m too novice in this to make sure, so any feedback on this would be fantastic.

Going through numerous topics on TTGO T-Beam and different examples, the board itself works and I’ve managed to upload code onto it, but I cannot seem to connect with the TTN. Any help or extra questions to give input to would be greatly appreciated!

PS. I am using The Things Gateway for testing.

Thanks!
-Tarvo.

BoRRoZ · March 27, 2019, 9:08am

see

Verkehrsrot · March 27, 2019, 9:21pm

If you have the older TTGO T-Beam Version you need to wire Lora Pin DIO1 to CPU.

You can also check paxcounter software which comes with tailored settings for TTGO T-Beam, perhaps it works on your’s. If yes, you know that you did something wrong.

Bercman · March 28, 2019, 6:27am

Thanks for the tip. Could You please elaborate to where I would have to wire the LoRa DIO1 in case I need to?
I’ve had a look at the Paxcounter before, but haven’t really tried uploading it to the T-Beam that as it seemed a bit too complex code to begin my exploration with, but I will try it out. Hopefully it reveal something.

EDIT: Paxcounter works fine, I was able to connect to TTN and forward data. So what mightbe up with the previous codes?

DeuxVis · March 28, 2019, 9:31am

Well first make sure you have a version which needs the wiring.

Can you find any version marking on the board ? Please copy it here.

Later : I just saw your edit. You definitely do not need more wiring if paxcounter works.

Verkehrsrot · March 28, 2019, 11:14am

Double-check your pinout and your keys.

Pinout of TTGO-Tbeam can be found here:

github.com

espressif/arduino-esp32/blob/master/variants/t-beam/pins_arduino.h

#ifndef Pins_Arduino_h
#define Pins_Arduino_h

#include <stdint.h>

#define EXTERNAL_NUM_INTERRUPTS 16
#define NUM_DIGITAL_PINS        20
#define NUM_ANALOG_INPUTS       16

#define analogInputToDigitalPin(p)  (((p)<20)?(esp32_adc2gpio[(p)]):-1)
#define digitalPinToInterrupt(p)    (((p)<40)?(p):-1)
#define digitalPinHasPWM(p)         (p < 34)

// SPI LoRa Radio
#define LORA_SCK 5      // GPIO5  - SX1276 SCK
#define LORA_MISO 19    // GPIO19 - SX1276 MISO
#define LORA_MOSI 27    // GPIO27 - SX1276 MOSI
#define LORA_CS 18      // GPIO18 - SX1276 CS
#define LORA_RST 23     // GPIO23 - SX1276 RST
#define LORA_IRQ 26     // GPIO26 - SX1276 IO0

This file has been truncated. show original

shadowkane · April 19, 2019, 4:26pm

i’m not sure if this is the right place to post my question about TTGO T beam. It’s my first ESP board and my very first project with ESP and lora. my question is simple, can i use my board without battery, just power it on using only USB (connected to PC). I already tried that because i though it’s fine, like almost every single board in the market has an USB port for power and programming, but the moment i turn the switch on i heard some noise.i’m not sure if the noise is from Lora component or not but i think it is, so i just turned off.

BoRRoZ · April 19, 2019, 4:43pm

why not

shadowkane · April 19, 2019, 4:49pm

“why not”
it’s the same though i had in mind when i was buying the board. if i can charge the battery from usb it means the usb can power the system on, which mean no need for battery if i want to work inside. but as i said, when i tried that, i heard some noise. (like a charger when it makes a low noise. i don’t know if you heard that before or not) but not a loud noise just noticeable.