Max/MSP to Arduino with Serial comunication and SimpleMessageSystem – controlling small DC vibration motors

Hello everyone,

I’m currently working on controlling mini DC vibration motors (low voltage) with Arduino, using CMD SimpleMessageSystem to communicate from Max/MSP. This setup was working before, but suddenly the motors stopped responding.

Here’s what I’ve checked so far:

• Hardware:

  • Motors are connected through MOSFETs (tested separately, they work).

  • Arduino board is receiving data (the TX/RX LEDs blink when I send commands via SimpleMessageSystem).

  • Power and wiring have been verified.

• Software / Communication:

  • Baud rate is set to 9600, and the correct port is selected.

  • With a basic serial communication patch in Max, I can see data arriving at the Arduino, but the motors still don’t react.

  • When I send commands directly through the Arduino Serial Monitor or Max’s internal terminal, the expected values are received correctly.

  • With the SimpleMessageSystem patch in Max, the terminal only displays the port number, but no messages or responses are printed. I’m not sure if this is expected behavior or if it indicates that something is not working.

• Observation:

  • Communication appears to pass from Max → Arduino (lights confirm this).

  • The issue seems to be in how the Arduino interprets or executes the commands when using the SimpleMessageSystem patch.

  • Individually, all components work (motors with MOSFETs, Arduino serial, Max patch), but combined under CMD SimpleMessageSystem, the motors do not activate.

I’m an artist using Arduino mainly for interactive works, so while I’ve tested the basics, I may be missing something in the software/firmware side.

Has anyone experienced issues with SimpleMessageSystem + Max patches (Arduino2Max/CMD module) where the Max terminal only shows the port number but no responses? Any guidance on whether that’s normal, or what I should check next, would be greatly appreciated.

Thanks in advance!