Greetings friends. A few months ago, I started writing articles and doing my own home projects on the topic of Meshtastic. You can see the results of my work in the following branches:
Several questions I get in private messages asking for more details on home projects. I have postponed this work for a long time, tk. it was necessary to collect and structure all materials and developments.
In this thread, I will upload my materials.
A small tabular selection of LoRa modules suitable for DIY.
I created a project on github, where I will upload all the materials.
Added an electrical circuit for modules E22-900 (433) M30S
Added an electrical circuit for modules E22-900 (433) M22S
Added modified firmware for these modules.
Added software for flashing ESP32 modules
Thanks for the hard work of exploring utilizing the high power E-Byte modules. The schematic is very helpful for those of us exploring some DIY boards of our own.
One other thing that would be helpful to see in the repository would be any configuration.h changes you made to target the build for that board.
Negotiations are underway with the author of the project to include the Meshtastic-DIY section in the official release. All variants of the configuration file will be available to everyone there, including for the DIY-project.
I also announce that circuit designs for E19 modules will be presented soon. There is also a lot of interesting things there.
Awesome! Thanks
I’m not familiar with the E19 modules, I’ll have to take a look at those.
Also of interest, EByte has some NRF based modules available.
It’d be pretty comical to have a board with one Ebyte module as the MCU and one as the LoRA radio. 
These modules are 2.4GHz. I don’t think this is a good idea.
Sorry, I meant the module I linked to above would be the cpu in a meshtastic device rather than the radio. That nRF52840 SoC it utilizes contains an ARM Cortex M4 processor. It’s a much lower power consumption architecture than the ESP32.
Since the RAK Wireless 4361 boards and the new TTGO T-Echos use that chip, there is precedence for targeting it. The problem is having to build out all of the ancillary circuits enable things like flashing the device via usb for instance.
A dedicated DIY firmware branch would be very useful for tinkers or anyone wanting to save money on nodes.
I would say a fork in github might even give a bit more flexibility.
No need for forks. All changes will be present in the special official Meshtastic-diy branch. If you want - use E22, if you want - use E19, if you want - ordinary noname modules with Ali.
E19 modules are no different from the SX1276/1278 firmware, with the exception of the rx/tx switching contacts. They are easily added and are already hidden in the radio lib library. In the same way as the rx/tx contacts for SX1262/1268.
In the special official branch of the Meshtastic-diy, all this will be present. A little patience!
Added electrical diagrams for E-byte E19 modules.
Special firmware for E19 will be added a little later.
Added an example document for home made assembly of a Meshtastic-modem in Russian and English.
I thank all the colleagues involved in the project!
Thank you for the translations!
Added an electrical circuit with different simple LoRa-modules with aliexpress based on SX1276/1278 for 868/433MHz.
Added an electrical circuit with Nice-RF LoRa-modules based on low-power SX1262/1268 and on the based of powerful Lora1262/1268F30 and Lora1276/1278F30 modules at 868/433 MHz.
Note 1: I recently purchased but have not tested the Lora1276F30 modules yet. I think there shouldn’t be any problems with them.
Note 2: NiceRF also has low-power modules based on SX1276/1278. I didn’t draw separate diagrams on them, because they almost completely coincide with the schemes of Noname modules.
Hello friends!
When testing the firmware, our colleagues discovered a bug in the definition of the RX GPS pin. I fixed the problem, rebuilt the firmware, now the GPS on pin 15 is working correctly.
Also, together with other colleagues, work is underway to write the FAQ. See the DOC section.
Awesome work!
Are there enough pins available to expose the JTAG port on the esp32? That would help developers debug the device much easier than current methods.
Thanks for your great work towards DIY targets!
I will give it a try as soon as I get my hands on the hardware!
Maybe you can also add provisions in the code to switch off the GPS module to save power? The t beam is using the APX192 pmic chip, but it could be a simple as a GPIO pin+highside switch to kill power to the GPS.
Greetings friends! Hi Kevin. @geeksville
Recently, a friend of mine who is involved in programming and modifying the main code has made support for the new LoRa chips CC68. These chips are a continuation of the SX1262/1268 series. In my opinion, these are “cheaper” chips of the best SX1262/1268, since these chips have a small drawback. They do not support the “default channel”. There is no parameter SF = 12 in the settings of the CC68 chip. And this parameter is one of the most important in the “default channel settings” mode. The minimum available mode for the CC68 chip is SF = 11.
Thus, it turns out that the chip seems to be supported by the firmware now, but the configuration should be for a particular case (individual setting) - one of the 3 settings available in the program, but this will NOT BE SUPPORT by default “#LongSlow-V” (Very long range, but slow).
I hope in the near future our colleague will make a pull request and support for the new chip will be added by Kevin to the main project.
For those colleagues who are engaged in independent experiments and know how to assemble the firmware on their own, a git-project with CC68 support is available here, in the CC68 branch:
