Working with SysEx and Firmata

Hi there,

we’re kind of newbies with vvvv and arduino, after some projects just running motors over pwm + pins we’re trying to get a stepper work by talking over IC2 protocol from vvvv to the stepper driver.

We’re a bit confused with the sysex messages. What we don’t get is how the proper sysex message send from v should look like and how a single command has to be sorted in the spread of possible commands then put as [Raw] to the ‘FirmataBoard’. We’ve been looking for IC2 libraries, the right commands and examples but couldn’t find something appropriate. We honestly also don’t get the full concept how to introduce it into the v4-patch plus how into the firmata code as IC2 adress.
Anyone knows about tutorials here or maybe some exaples to learn?? Help!!

We’ve got a bipolar stepper motor on an adafruit motor shield, vvvv beta 50_35 x64

Thanks a lot!!

Dirk & Christian

Hi apnoe,

please check these Nodes:

  • I2CRead (Firmata)
  • I2CRead (Firmata Continuous)
  • I2CWrite (Firmata)

Note, we didn’t had a chance to properly test them, would be great if you would try it and report.

p.s. I guess we have to cover I2C topic during the Workshop as well.


Hello, I have the same problem like apnoe. I am trying to control LEDs through the Adafruit PCA9685 16-channel 12-bit PWM board connected to an arduino Uno. This kinda works while i try this by integrating the Arduino_DataAsStrings Sketch from the girlpower folder into another adafruit example sketch. But I am experiencing problems when i try to send too much data to multiple LEDs. Because I do not fully understand the Arduino Sketch and the Adafruit library I was thinking maybe using Firmata would be anyway the better idea. I am looking at the Firmata - Advanced Usage Patch from the girlpower folder and it looks easy, but like apnoe i dont really get the idea, how things connected to the I2CWrite Node should look like, most of all to the Input pin. I also tried to have a look at I2CWrite (Firmata) help patch, but i feel like it is not well commented and i dont get the idea what should happen in this help patch. Could anyone help? Please let me know if any screenshots or additional data is needed :-)

Thanks a lot

Hello victor_tb,

in the Alpha downloads, you’ll find one very well documented example on how to use I2C with Firmata.
Note, that talking via I2C protocol needs you to read the documentation of your device very carefully and exactly follow the commands that needs to be issued.

The example is then in your vvvv installation:


This topic was automatically closed 365 days after the last reply. New replies are no longer allowed.