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Created by @sameer-kulhari

Total Time Spent : 24hr

Project Journal – DIY ELRS Transmitter Module

By Sameer Kulhari

June 8th: Designed the idea and working of the project

Today, I figured out the full concept of how my transmitter module will actually work and how I can build it from scratch. I spent a lot of time researching how professional transmitters like Radiomaster, Jumper, and Flysky are built and what features they have.

One cool thing I found is that most of the mid to high-end transmitters support ExpressLRS (ELRS) β€” which is open-source! That was a big moment because it means I could also use ELRS in my own DIY transmitter module.

After all the research, I now had a clear idea of what I wanted to make β€” how the transmitter will function, what components it’ll need, and even how it should look. I drew the full plan on paper.

Total time spent: 4.5 hours


June 9th: Designed the schematic and PCB for ELRS-TX

Today I moved from planning to actually designing. I used KiCad to create the full schematic and layout for my ELRS-TX board.

Once the PCB was ready, I exported the gerber files, added all the libraries, and uploaded layer images and a 3D view of the PCB to my GitHub repository so everything stays well-documented and reproducible.

Here are a few images from the repo:

Total time spent: 3.5 hours


June 10th: Updated PCB and added new parts for ELRS-TX

Today I focused on upgrades and made the board even better!

I first created a list of new components that I could add to make the transmitter feel more pro-level. After that, I updated the schematic with these parts and redesigned the PCB to make it modular β€” so the ELRS-TX board can be plugged in easily and used as a plug-and-play module.

New features I added:

  • Cooling fan for stable performance
  • NeoPixel for status indication
  • New power input option

The final schematic looks clean, and the new board layout is compact and efficient.

Total time spent: 4 hours


June 12th: Started designing the case

Today I worked on the outer casing of the transmitter. I took all the dimensions from the PCBs and components and then used Onshape to start designing the case.

It’s still in the prototyping stage, but the fit looks really good!

Here are some preview pics:

Total time spent: 5 hours


June 13th: Parts sourcing + README update

I researched and finalized where to buy all the components β€” including the ESP32, E28 LoRa module, OLED, and other parts.

After that, I updated the README file and this journal log to include all the new changes and features I’ve added over the last few days.

Now the project is fully documented and ready to share!

Total time spent: 3 hours