ESP32 Marlin Control

Send Gcode to Marlin from ESP32 using a serial connection.

Installation

Tested on RaspberryPi OS but runs on any platform supported by Python 3.6 or newer.

Checkout source code:

git clone https://github.com/thijstriemstra/esp32-marlin-control.git

Install pyserial:

python3 -m pip install pyserial

Install esp32-marlin-control:

cd esp32-marlin-control
python3 -m pip install -e .

You should now be able to use the esp32-marlin-control commandline tool, e.g:

esp32-marlin-control --help

Usage

Start the tool by supplying the ports used by the Marlin and ESP32 devices connected to your machine.

For example, with Marlin connected to /dev/ttyUSB0 and ESP32 connected to /dev/ttyUSB1:

esp32-marlin-control -v --marlin-port=/dev/ttyUSB0 --esp32-port=/dev/ttyUSB1

On the Windows operating system COM ports are used instead:

esp32-marlin-control -v --marlin-port=COM3 --esp32-port=COM4

Static port names

If the port names keep changing and you want to reference the device by a name that doesn't change (for example /dev/marlin instead of /dev/ttyUSB0), try the following.

First, list the connected USB devices:

lsusb

Next, create a udev rules file called /etc/udev/rules.d/100-usb-serial.rules with rules for the board running Marlin (/dev/marlin) and the ESP32 controller (/dev/esp32).

Make sure to replace the idVendor and idProduct values for each device (that can be found using lsusb). For example:

SUBSYSTEM=="tty", ATTRS{idVendor}=="1a86", ATTRS{idProduct}=="7523", SYMLINK+="marlin"
SUBSYSTEM=="tty", ATTRS{idVendor}=="10c4", ATTRS{idProduct}=="ea60", SYMLINK+="esp32"

Restart udev to load the new rule:

sudo udevadm control --reload
sudo udevadm trigger

The devices can now be referenced using /dev/marlin and /dev/esp32:

esp32-marlin-control -v --marlin-port=/dev/marlin --esp32-port=/dev/esp32

Run as background service

Create a systemd unit file at /etc/systemd/system/esp32-marlin-control.service. Make sure to replace --marlin-port and --esp32-port with the correct ports, and set the correct path for the esp32-marlin-control application:

[Unit]
Description=ESP32 Marlin Control
After=multi-user.target

[Service]
Type=simple
Restart=no
ExecStart=/path/to/esp32-marlin-control --marlin-port="/dev/marlin" --esp32-port="/dev/esp32"

[Install]
WantedBy=multi-user.target

Enable and start the service:

sudo systemctl daemon-reload
sudo systemctl enable esp32-marlin-control.service
sudo systemctl start esp32-marlin-control.service

View log with:

journalctl -f -n 50 -b -u esp32-marlin-control.service

ESP32 example code

Once the esp32-marlin-control tool is running it will listen for serial messages from the ESP32, and forward them to the board running Marlin.

Simple example that demonstrates sending GCode from the ESP32 to Marlin:

#include "Arduino.h"

#define SERIAL_BAUD_RATE 250000

void setup() {
  // start serial connection
  Serial.begin(SERIAL_BAUD_RATE);

  // M119 (show endstop status)
  Serial.println("M119");

  // M84 (disable steppers)
  Serial.println("M84 X Y Z");

  // make controller board beep
  Serial.println("M300 S300 P100");
}

void loop() {

}