How to send and receive variables of the type strings with Heltec Lora ESP32 V3

I am working in the Arduino environment, with String type variables. I am not an expert in programming, so I would like to evaluate an example in which String variables are sent through LoRa, with the ESP32 V3 module.

I thank you in advance for any help you can give me.

I’m not sure about the protocol for advertising third party websites, but the discussion on my project website at

includes the mechanism I use to transmit data of any structure using LoRa.


Hi, I’m sort of intermediate to arduino ide, but have no real lora or network experience, so this is pretty tough to conceptualize. But it seems really close to what I want to accomplish.

Can you help answer a couple of questions?

First off I have a lora32 v3 and plan to get more if this works. I also have a few devices that can sent text messages via lora (these are fully programmable with arduino IDE, so I can control frequency and all other signal perameters).

I got the factorytest firmware running on the lora32 v3, and was able to compile with no errors, so that’s step 1 I guess.

What I’m trying to make, is a mesh network of signal repeaters (or just 1 repeater if i cant mesh). So for example, I want to send a lora transmission with a text string from my lora radio, have a my heltec lora32 v3 recieve it, and re-transmit it so my brother who is just out of range can see it on his handheld lora texting radio. If I get more lora32’s in the future, I’d like them to mesh repeat as well. But tbh, I’d be happy with one repeater for now.

So questions:

  1. I guess, can you explain what your mesh network does vs what I am hoping to do?

  2. I might be able to look harder and find this out myself… but I haven’t figured it out yet. But is there a master download of working ini+library files for your repeater system that I can test flash to my lora32 v3 and kind of reverse engineer a little (it’s for private use so I won’t share it)?

  3. Any advice for a newbie like me for accomplishing my goal?

Thanks in advance, I really appreciate it!


I’m not really using a mesh network, at least not in the way I’d describe a mesh network. I just have several LoRa Nodes transmitting data and one ‘Gateway’ Node receiving that data via LoRa and forwarding relevant MQTT messages to a ‘nearby’ broker via WiFi.

To configure a LoRa repeater, in its most basic form, all you’d need to do would be to have a Node that simply retransmitted everything that it received. Now, that arrangement would come with its own set of ‘restrictions’. The repeater in this configuration would be doubling the amount of traffic in your network. Further, any other receivers would potentially be receiving transmissions twice. These issues may or may not be a problem for you. A LoRaWAN network would manage this a whole lot better, but it would also be significantly more expensive.

All the necessary sketches are available from the website in the previous post, but there is a bit to get across there if you’re starting from scratch. It might be better at this stage if I send you a PM and we take further ‘instructions’ off-line.