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 :-)

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

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 Arudino TX Mara to RX Arduino 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 :-)

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

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

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

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