Ttgo T-beam


(Rhinoteknl) #75

Hi,
I copied the same code to my TTGO-Tbeam device and there is no compiler error , uploaded smoothly with my device addr and config.

but the device shows no connectivity on TTN console side.

Please help.


#78

@ jazzip0 - if you read this… excuses but I noticed that the system was thinking you’re a spammer.

and I can’t ‘undo’ this


#80

Would it be an idea to use wifi to get location when the gps data is not valid? That way you could keep following your pet indoors.
The downsides here are that the unit is more sized toward a car or an ebike and that it seems to be rather power hungry on battery. Any progress on that? I’ve seen a sketch that delays sending when the position did not change, that should already make a difference.


https://ictoblog.nl/2018/11/25/ttn-mapper-versie-2-ttgo-t-beam-eerste-resultaten


(Deux Vis) #81

@paulb : I’m not working on that project at the moment, but I definitely will integrate any improvements other people are publishing at some point.

If you want it faster, a great way to help is to submit a pull request on github.


(Rem73) #83

Hello,
After many investigations i have the solution to improve the poor level of transmit power on Lora TTGO version 1 at 868 Mhz ( I suppose it is version 1.) The lora TTGo like this :

There are 2 issues :
Software :LMIC library is not clear on this side : Check radio.c file, and go to SX1276 power definition ( about line 476 ) : add this at the end of configuration file: writeReg(RegPaConfig,0b01111111) : It suppose you have a hardware witout Paboost connected.

Hardware:Is low cost, interresting but poor RF design. I remove all the parts at he RF filter. I apply the Semtech ref design to changes 8 capacitors and inductors, and use Pa output without Paboost option
https://www.semtech.com/uploads/documents/SX1276MB1MAS_e315v01a_prod_folder.zip

Measurement are performed with radio laboratory equipement in conducted condition : about ±0,1 dBm absolute accuracy. That’s my job.

Before : 2dBm : about 1,6 mW ( with LMIC modification describe above)
After : 14dBm : 25mW. ( with LMIC same modification describe above)

Conclusion : some issue around lora TTGO could be the result of wrong parts…Simply apply Semtech refdesign could solve the issue, without hard optimisation, without network analyser and PCB effect compensation.

I don’t check the receiver parts. May be some errors on design again…

You cannot have this kind of issues with RFM95 module.


#84

buying a new one is probably cheaper… time is money :wink:


(Verkehrsrot) #85

but sure that the newer versions does not have these or other flaws in RF design?


(DarkMan) #86

nice. tnx.


(Rem73) #87

“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…


#88

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


(Rem73) #89

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


(Ud Lo Ra) #90

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.


#91

tnx… Andreas was spotted at The Conference yesterday ! :sunglasses:


(Ori) #92

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


(Eric VdB) #93

Wifi ?


#94

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) #95

Not good for the Lora antenna then…


#96

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


(Ori) #97

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


(Bercman) #100

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.