belectronic / marax-monitor-mqtt

Lelit Mara X (V2) data visualisation with an automatic Shot-Timer

MaraX Monitior with MQTT - Visualisation for the Lelit Mara X (V2) with an automatic Shot-Timer

This project is for anyone who wants to make their Lelit Mara X (V2) espresso machine smarter. Fortunately the MaraX has a serial interface providing some data that can be read! The project is a fork from https://github.com/SaibotFlow/marax-monitor. Inspirations came also from https://github.com/alexrus/marax_timer and from https://github.com/Vin-X-Mod/OLED-Splash-Screen-LOGO/tree/main.

Versioning

I use a Pythonscript for generating a version.hpp for transmitting a version via MQTT. If you don't need that, or if you don't have python installed please remove the line extra_scripts = pre:lib\Version\version_gen.py* in platformio.ini.

Parts

• ESP32 Node MCU (You can use any other equivalent board)
• USB Cable with power supply for ESP32
• Jumper-Wires
• 0,96" SSD1306 OLED Display
• 3D printed case https://www.thingiverse.com/thing:2937731

Structure & Connections

The Interface

The MaraX has a 6-PIN Connector for the serial interface on the bottom. We only use PIN-3 (Mara RX - Black Wire - Green Rectangle) and PIN-4 (Mara TX - Orange Wire - White Rectangle). For testing you can use the jumper-wires later you should replace them with temperature protected cables.

• PIN3 Mara to TX2
• PIN4 Mara to RX2

RX Mara to TX2 ESP32 and TX Mara to RX2 ESP32

The connector for serial interface itself

Note: A Reed sensor on the vibration pump is not necessary for the MaraX anymore as the interface provides the pump status information now.

The Data

You will receive the following data each ~400ms.

Example Data: C1.06,116,124,093,0840,1,0\n

• The delimitter is: ,
• The end of data is: \n
• Length: 26

Data	Description
+	Machine-Mode (Model 2022): + = CoffeeMode; C = SteamMode
1.06	Firmware
116	Current Steam Temperature in Celsius
124	Target Steam Temperature in Celsius
093	Curent Hx Temperature in Celsius
0840	Countdown Boost-Mode
1	Heat state (0 = off; 1= on)
0	Pump state (0 = off; 1= on)

Display Wiring

Pin Display	Pin ESP32
VIN	3.3V
GND	GND
SCL	D22
SDA	D21

The address selection is 0x3D or 0x3C. You can recognize it by the solder bridge on the back side

WIFI & MQTT

By editing the credentials in espwifi.h and mqtt.h you can transmit the MaraX data to your MQTT server.

Here are the preconfigured topics:

Topic	Payload Datatype	Description
marax/mode	Char	Machine-Mode
marax/steam/temp/current	Int	Current Steam Temperature in Celsius
marax/steam/temp/target	Int	Target Steam Temperature in Celsius
marax/hx/temp/current	Int	Curent Hx Temperature in Celsius
marax/heating/state	Int	Heating state
marax/pump/state	Int	Pump state

Libaries

• Wire.h (OLED)
• Adafruit_GFX.h (OLED)
• Adafruit_SSD1306.h (OLED)
• PubSubClient (MQTT)