BIG ESP32 / SX127x topic part 1

(Deux Vis) #104

That is a single model that can do 868 to 915 Mhz.

You set the frequency by software.

For instance in LMIC sample code it seems to be achieved by the LMIC_setupChannel() calls - but I didn’t test changing it as the example code was set for 868.

If you just wanna do Lora (not Lorawan) you have to use the library provided by Heltec and call LoRa.begin(BAND) with BAND being 868E6 or 915E6.

(Rmh78) #106

Just found additional options for the deep-sleep mode. Looking inside the esp_sleep.h the function esp_sleep_pd_config can be used to configure the sleep.

I added this include.
#include "esp_sleep.h"

And before every sleep call I set the config.

esp_sleep_pd_config(ESP_PD_DOMAIN_MAX, ESP_PD_OPTION_OFF);

I reduced the power consumption to 2mA (also powered the esp32 with 3.3V to prevent the blinking led).


Apologies, I meant to answer this earlier. I did indeed compile with:



Thanks. No need to apologise. :grinning:

I had already discovered it, but that also helped me discover a versioning inconsistency in arduino-limic (see below).

(Biohazard) #109

Sadly, your code doesn’t change the power consumption of my heltec lora dev board.
In comparaison, with the esp32_core_board, with the same code, i got 2 mA because of the power led: in the µA range if led removed.

If you achieve better results, maybe you own another board or maybe there are some differencies in the components used.


Note to PlatformIO users:

There seems to be a versioning inconsistency in the “IBM LMIC framework” aka “arduino-lmic” library.
The libraries on GitHub and PlatformIO (Registry ID: 852) have identical versions but the libraries are different. The library on GitHub is newer. Until the versioning has been fixed it is preferred to use the library from GitHub.

Further explained here: Apparent versioning inconsistency in arduino-lmic libraries

(Rmh78) #111

I have created an issue on the heltec github page.
Hopefully they can help :wink:

(Franc Kralj) #112

has already managed to connect to a thethingsnetwork.
How did he do it?

Thanks for the deal.


Probably will not add nothing to the discussion but since I’ve found out that the PltaformIO lib was out of date, I’ve just “git cloned” the library from github under the lib directory, and the project finds the LMIC files there with no issue.


Yes, that is just what the Lib directory is for, manually adding custom libraries. :wink:

That does however not use one of PlatformIO’s strongest features: automatic library handling / semantic versioning.

(Biohazard) #115

I saw the answer on heltec github. With the oled commands added, it doesn’t change the power consumption.
Hope you’ll be luckier.


what additional libraries and codechanges did you made?
I tried #include <SSD1306.h> and initalizing that, but I still gett errors @display.sendCommand(0x8D)
btw I measured 9.4mA while deep sleep, 56mA while running

(Rmh78) #117

Also not lucky for now. I posted my results in the github issue. Looking forward to here an other approach from heltec team.

(Panda) #118

hello. im new to lorawan and im trying my first examples.
i have two heltec lora but they work in 433mhz.
i also check in the lmic link but i cant find the 433mhz definition
idk if i can use them as nodes.
any help please


you can not use them as nodes on the TTN network which operates on the 868 mhz.

(Jac Kersing) #120

Anyone looking for a cheap, easy to assemble (no soldering required) single channel gateway, get one of the Heltec (or alike) modules and grab a copy of the things4u ESP-1ch-Gateway code modified to run on the WIFI-LoRa-32 868MHz boards.

A huge thanks to Maarten for providing the code for ESP8266.


Got one of the heltec clones (TTGO) with oled. First look and tests with GPS forwarding looks great. Want to build a use case for an emergency button GPS location or movement tracking device for my car.



Anyone has tips for easy integration with google maps through TTN?


(Rmh78) #122

I also developed a GPS/LoRaWan tracker which displays the path on a open street map. I used node-red as integration platform to receive the TTN message and display the location on a world map. For the map I used the node-red worldmap plugin ( This plugin integrates leaflet ( into node-red.

Super easy, super cool :slight_smile:

(Biohazard) #124

Today I sacrified one one my four Heltec LoRa dev board and removed the oled display (unsoldered oled ribbon cable).
The board is still draining the same 10 mA in deep sleep.

(Biohazard) #125

Ok then I removed the sot-23 I think is (was…) the battery managing system, maybe an mcp73831. Still 10mA.
Then I removed the other sot-23 just below. I think it’s the LDO.

In deep sleep, the Heltec in now draining 2.6mA.
Removing the two leds did not change the power consumption.