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

Hello everyone! This project is for anyone who owns a Lelit Mara X (V2) espresso machine. When looking for a new espresso machine, one feature I always wanted was a shot timer. Usually the machines are beautifully designed so I didn't want to ruin the look by adding a $5 kitchen timer to the machine. So far so good. Now you are going to say : Dude the MaraX doesnt have a Shot-Timer?! Yes, you are right but the MaraX has a serial interface! As a developer and tinkerer a ready to use serial interface is more interessting then a ready to use Shot-Timer ;)

If you like my project, please give me a star and if you want, you can also buy me a coffee :-)

Updates

• New file include marax_monitor_wemos_wifi.ino included.
• Supporting Wemos D1 Mini Pro (ESP8226) with WLAN.
• Sending Push-Notification when machine is hot via Pushsafer-Service

How to use this repo?

This repo should help you to implement your own solution. I implemented my personal solution, probably it fits to you. If not you can change the code yourself. I commented the code a bit to show what happens where.

There are 2 Files

• marax_monitor.ino
• marax_monitor_wemos_wlan.ino

The marax_monitor.ino is my first solution. I used an Arduino Nano for that.

The marax_monitor_wemos_wlan.ino is a more smart solution. In that case smart means: It sends a push notification when the machine is ready (not hot). For me the machine is ready when:

data.steamTemp == data.targetSteamTemp && data.hxTemp > 90 && initialPushSent == false

I used a Wemos D1 Mini Pro - small board and WLAN out of the box. You could easily extend this solution e.g. adding a WebUi or pushing the data to a server. There are many ideas.

Secret data

SSID, WLAN-Password and API-Key are sensitive data and should not be pushed in an open repository. So I created a .gitignore which is ignoring the file secrets.h in the sketch-folder. In this file you can put your secrets like that:

 #include WLAN_SSID "SSID"
 #inlcude WLAN_PASS "PASS"
 #inlcude API_KEY "MyKey"

Push Service

For sending push notifications I am using the PushSafer-Service. It is easy to use and I already had experience with it. But you could change your service as well. So you have to change the sendPushSaferMessage Method, the host and the port.

Note:

If you dont want to send any push notifications you can set bool initialPushSent to true then the programm will not send any push notifications. You can change title, message, icon etc. here:

 String pushTitle = "Lelit%20Mara%20X";
 String pushMessage = "I%20am%20hot%20for%20you!";
 String pushIcon= "62";

Parts

• Arduino Nano / Wemos D1 Mini Pro (You can use any other equivalent board)
• Breadboard
• Jumper-Wires
• 0,96" SSD1306 OLED Display

Structure & Connections

Important: If you use a Wemos or any ESP8266 board you have to connect:

• SCK/SCL to D1
• SDA to D2

Arudino is using A4 and A5 Pin

• SCK/SCL to A4
• SDA to A5

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 D6
• PIN4 Mara to D5

RX Mara to TX Board

TX Mara to RX Board

You will receive the following data each ~400ms.

The serial interface itself

Note: I also did some tests with a reed sensor and the vibration pump. However its not necessary for the MaraX the interface provides the information about the status of the pump. Maybe I will do another project for a Shot-Timer only for espresso machines with a vibration pump only :-)

The Data

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

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

Data	Description
C	Machine-Mode: C = CoffeeMode; V = Vapour/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 Board(Arduino/ESP8266
VIN	3,3V or 5V
GND	GND
SCL	A5/D2
SDA	A4/D1

The reset pin is 0x3D or 0x3C. You can recognize it by the solder joint on the back side

Libaries

• Wire.h
• Adafruit_GFX.h
• Adafruit_SSD1306.h
• SoftwareSerial.h

Additionaly for Wemos / Esp8266

• ArduinoHttpClient
• Esp8266WiFi
• SPI.h