To cut down on wire runs, I would like to power motor encoders using the 3.3v auxiliary power pin of Big Easy Driver stepper motor drivers, but I wonder if it's safe to have multiple 3.3v sources tied to the Raspberry Pi's own 3.3v source.
Currently, I am powering each encoder from the Pi's 3.3v supply and using 2k-ohm pull-up resistors from the same to the SDA/SCL line on each encoder; this method works great to eliminate motor current noise from interfering with the i2c signals. Will I cause problems if I power the encoders from the BED at the motor AND pull-up the SDA/SCL lines at the Pi? Perhaps I should add diodes between the pull-up resistors and the Pi's 3.3v? All grounds will be tied together. Thanks!
Currently, I am powering each encoder from the Pi's 3.3v supply and using 2k-ohm pull-up resistors from the same to the SDA/SCL line on each encoder; this method works great to eliminate motor current noise from interfering with the i2c signals. Will I cause problems if I power the encoders from the BED at the motor AND pull-up the SDA/SCL lines at the Pi? Perhaps I should add diodes between the pull-up resistors and the Pi's 3.3v? All grounds will be tied together. Thanks!
Statistics: Posted by loudboy — Sun Jul 13, 2025 1:11 pm