Reach + Adafruit Feather 32u4 RFM95 LoRa Radio-

[andresc4 (Andres Alvarez)]

Hi all
Im new to Reach, I just followed the quick start guide, I was able to make base+rover get a fix possition over WLan
Next step is to test the devices on the field and get data to post process.

I was sure that I had 2 3dr Radios, but I dont
But what I do have is a Adafruit Feather 32u4 RFM95 LoRa Radio that have an amazing rage
and a pair of SX1278 connected to a ESP32 running arduino , they also work great, just in 433mhz

As I understand the data bewteen rover+base is only one way… I would like to capture the data of the base, send it to an esp32 over serial, and use the Esp to send it to SX1278 over Lora, the other ESP32 will do the opposite job.
I can do it with the Adafruit Feather 32u4 RFM95 also, but my question is…

Does it make a difference if the package arrives a few miliseconds latter from the base to the rover?
How long is the string that is sent from the Base to the Rover, and does it have any “ending” character ?
I not sure if I can send lora packages byte by byte, thats why I was thinking in parsing a group of characters, but Im not sure how long they are… I did not found any topic related to Lora+Arduino+Reach, but Im sure this is not a “new” idea… ca you guys point me to what topics/documentacion should I read before start this ?

[egor.fedorov]

I think this will be quite easy if you use a UART connection. RTCM3 corrections are binary, so no need to parse them. Our docs contain some info on the bps rates.

The small delay should not matter, the important thing is for the corrections to arrive regularly and in a stable fashion.

[andresc4 (Andres Alvarez)]

Great, so I can just configure my arduino sketch to send each byte by LoRa radio,no matter what is the message…
I will give it a try and let you guys know.

[guillaug]

It works, I have done it using a similar method (UART + LoRa 433Mhz), using a hard coded data rate.

But could not find the time to share.

My strategy : Arduino buffers the bytes sent by the base via UART, it then fills a packet entirely (packet length and bit rate was fixed for sending only specific messages), then sends it over LoRa.
If you stream bytes as they go you are not optimizing air time so you have more delay (and less stability i found).
I have an issue sometimes though : if the LoRa connection drops a byte or a packet, then the rover looses count and can’t process new packets and decode the messages. When I have time I would like to implement some CRC check.

Send me a message if you’re interested

[andresc4 (Andres Alvarez)]

Hey gulliaug Im totaly interested, please send me a PM or andresc4 at gmail
I have 2 chinese 3dr radios, but they are not working at all, well they do work on shot distances for a few minutes, but they die, connection get lost, and i need to restart the reach modules in order to make them work, they are not reliable at all.

I did though about what you say, lora its slow to send byte by byte, I was thinking on raising a flag if a byte is not recived for more than x miliis ( I need to measure, time between each RTCM3 message ), to know then the package “ends” , because there I did not found any ending character. and send that all at once.

The problem is that i am not sure how to make a serial read over a binay stream, I neved done it, and to be honest I did not give it a try yet. If you already done it, please I would like to use your aproach and keep implementing thins over it.

I have 4 lora modules, 2 915 Adafuit Feather 32u4, and 2 other Ra01 433 modules alone, I was able to make them work over a ESP32 I think this is the best way to go because they are cheap and super powerfull.

I also made this other project using a UBLOX Neo6 GPS and a esp8266 + oled display, I was using a library do decode nmea messages, in order to get position data, aquraci, and distance to another point. I would love to have 1 esp32+oled+ra01 that recives Lora messages and at the same time read the nmea out from the rover to show me Age of differential / Ar validation Ratio, and battery level, and if I have or not have a FIX
By doing this I can have a fisical button and use a sd card or the same esp32 memory to store points without the need of any other hardware

I can upload the code and schematic for this esp32 + ra01 if you want to give it a try, but there are lots of board that have this 2 things already made so you dont have to do this mini wiring mess

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