Big ESP32 + SX127x topic part 3

(Petervande Pol) #130

I am working with a TTGO Lora32 V2 and have tried the examples from the Arduino-LIMC library by Matthijs Kooijman. It looks like I have the board working: with both the ABP and OTAA examples I see action on my gateway. In ABP mode only one hit, in OTAA mode I see a join request, a join accept and then an uplink. However: this happens only once on power up or when I hit the reset button. I assumed that I would see a continuous series of messages. The code says that the TX interval is 60 seconds, but nothing happens. To be clear: in both ABP and OTAA only once a packet is handled by the gateway.

When I go to the application I can see how long ago the board was powered on, but both the Frames up/Down counters say “0”

Am I wrong in my assumption that I should see a message every 60 seconds? My gateway is made of a iC880A-SPI concentrator board with a Raspberry. I know that the gateway works since when I power up another node (a LSN50 I see a continuous stream of packets coming in.

(Lennyz1988) #131

Thanks! I tried what he did in the link. I tried adding 20k pull-up resistors on Mosi, Miso, SS and CLK. I now got the standby consumption reduced to 154uA!

Should I use higher or lower resistors?

(LoRaTracker) #132

Try it and see.

(Tavisg) #133

I have two Heltec Lora V2 boards and even though I’ve been having some intermittent consistency problems I’m excited today because I got successful 2 way data transmission at 12.4 miles distance.

(Sandgroper) #134

Higher value resistors will not improve the current consumption in sleep as these lines are only floating. However, if you have these pull ups connected to the supply rail it means that the current consumption would be higher when the processor is not in sleep state.

(Eric VdB) #135

Have you tried this library:


(Tavisg) #136

Is anyone else having issues while using the Heltecs board for both rx and tx ? Whenever I use one of these boards to send and receive via LORA they seem to get stuck in RX mode or a TX mode ? A board will receive a “request” packet and then try to transmit a data packet. The packet seems to send but doesn’t actually send. If I reset the entire board then transmitting starts working again. I’ve tried resetting just the LoRa module but that doesn’t seem to help. When I set up the devices so that they only ever send or receive (but not both) then they work just fine with no hiccups. I’m currently using the radiohead library to operate the LoRa radios.

(LoRaTracker) #137

It does sound like an issue with the Radiohead library on ESP32, not sure if its 100% supported. You might find more users of that point to point LoRa library over in the Arduino forums.

(Tavisg) #138

I’m seeing the same problems with Heltec’s own library though so I don’t think it’s RadioHead.

(LoRaTracker) #139

If this is Heltecs LoRa point to point library, then users in this TTN forum may not have a lot of experience with that library or the Radiohead one.

Not heard of similar problems when using the ESP32 for TTN, but maybe I have just not been paying attention.

(Verkehrsrot) #140

Heltec’s “own” library is based on Radiohead lib.
And radiohead lib does not support LoRaWAN, neither checks DIO1 status pin of SX1276.

Use MCCI LMIC and get things up and running in less than 15 minutes.

But beware of other design flaws in the Heltec boards, esp. V1.

The 2,4 GHz RF circuit achieves poor results with paxcounter. Don’t know why.

(Dave Calway) #141

Hi everyone,
i bought the ESP32 Heltec v2 and followed the main guide.
I have found some problems:

//LMIC LoRa module pin configuration

//For ESP32 Heltec v2 use:
const lmic_pinmap lmic_pins = {
  .nss = 18,
  .rxtx = LMIC_UNUSED_PIN,
  .rst = 14,
  .dio = {/*dio0*/ 26, /*dio1*/ 35, /*dio2*/ 34}

To use the build in Oled the U8g2 library wants these pins:

U8X8_SSD1306_128X64_NONAME_SW_I2C display(/* clock=*/ 15, /* data=*/ 4, /* reset=*/ 16);

and yes, Software -SW- not Hardware -HW- .

I edited the ttn-abp/otaa example, from lmic library, adding the correct definitions for Oled pins and LoRa module for the ESP32 Heltec v2:

Plus if you uncomment #define DEBUG_OLED you can see the the Serial output on the Oled screen.

I hope that help someone!

(Arcos) #142

Pls can you help me, what is this component ?


(LoRaTracker) #143

Does not look like a component at all.

Maybe solder pads for attaching a ribbon cable for a display maybe.

Whats the board ?

(Elidee) #144

Looks like the pads for the oled display.IMG_0955IMG_0956

(Verkehrsrot) #145

It’s a printed on board capacitor acting as backup power source :clown_face:

(Arcos) #146

thank you for your answers


It looks more like a touch slider control for adjusting the RF power. :nerd_face: :wink:

(Paul Stewart) #148

I have a TTgo V1 that the microUSB port has come off.

The fine pins are beyond my soldering capabilities, so is there any other way to communicate with the board eg through the RX/TX pins?


(Arinze Izukanne) #149

Yes, it should be possible. According to the schematics, the RX/TX pins are connected to a CP2102 USB-UART bridge controller. If you have USB-UART module like this below you can connect to the ESP32.