ESP32 Joystick2PPM board V2

A project log for A poor man's FPV journey

If you want to enter FPV world in a cheap way, read these pages !

JP GleyzesJP Gleyzes 12/18/2022 at 17:010 Comments

Principle of operations

Like the V1 board a PPM frame is generated by the MCU. 

I have choosen an ESP32 board for that (more modern than the old PIC18F4550).

As this MCU does not have an USB interface, I have connected it to a mini USB host shield based on the MAX3421 chip

The ESP32 lolin Lite board is mounted in "Mezzanine" above this shield, the result is a quite compact device that can be powered by a USB powerbank.

It has a USB A female port to connect the joystick and a Jack female port to connect to the radio's trainer port.

All this can be hidden into a 3D printed case which is available on Thingiverse.

Configuring the board

As this new setup works without Android App, I had to find a way to introduce a kind of Man Machine Interface to configure the board.

I have simply used the ESP32 WifiManager  library capabilities to do this.

So if you boot the board (or reset it with the reset button) while touching the small pin close to the jack connector, then the ESP32 exposes a Wifi hotspot on which you can connect any smartphone (or PC)

Connecting to it will automatically open a configuration window

You then have to choose an exisitng wifi network for which you have the credentials, enter them into the form 

Then you can change the magic sentence "RETAUL13" to configure the 8 channels of your board.

You can affect any stick, any button( 1 to 8) and hat to any channel. The syntax is simple :

REATUL12 meens:

And that's it, click on save and wifi will disapper while the board reboots and outputs the PPM signal.

So if you want to change this setting you can for intance write : TRAE123L

This will configure this way:


Well nothing complex here. Just connect the ESP32 board to the USB Host shield...

SImply note that the 5V supply for the shield is pick up after the USB plug of the EPS32 board. (red wire on the photo). SO a single USB power bank will power both the ESP32 and the USB shield.


A quite simple PCB has been home made. 

leading to a very compact form factor

You can download the eagle files here